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Learjet 20 Series, Pilot Training Manual

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the outflow valve when the differential be-
tween atmospheric pressure and cabin pressure
reaches a preset value. The preset value for
model 23 airplanes is 8.3 psid and for model
24, 24B, and 25 airplanes, 8.77 psid.

RATE Control

A knob on the left side of the cabin altitude
controller dial normally rests in a detent po-
sition and provides a 600–700 foot-per-minute
climb and descent rate. Pulling out the knob
and rotating it left or right decreases or in-
creases the rate of climb or descent.

Cabin Altitude Manual
Control Valve

On SNs 23-003 through -039, a three-posi-
tion, spring-loaded cabin altitude switch can
be used to position the outflow valve if the au-
tomatic pressurization control system fails.
To  use the switch, the mode switch, on the
controller, must first be positioned to MAN.
Then, holding the cabin altitude switch to UP

or INCREASE will open the outflow valve
and the cabin will climb. Holding the switch to
DOWN or DECREASE will close the outflow
valve and the cabin will descend. On most air-
planes, this switch has been replaced by a man-
ual cabin altitude control valve, such as those
installed on later airplanes and described below.

On SNs 23-030 through 24-229, and 25-003 and
subsequent, and as a retrofit on earlier air-
planes, a manual cabin altitude control valve,
commonly called the “cherry picker,” is pro-
vided to control the outflow valve if the auto-
matic pressurization control system fails. This
three-position valve, spring-loaded to the cen-
ter, is labeled “UP–DN” or “INCREASE–DE-
CREASE.” When the valve is held to UP or
INCREASE, the outflow valve will open and
the cabin will climb. When the valve is held to
DN or DECREASE, the outflow valve will
close and the cabin will descend. The valve is
operational with the mode switch in AUTO or
MAN. However, if the mode switch is in AUTO,
when the cherry picker is released, the outflow
valve will revert to automatic control.

12A-8

FOR TRAINING PURPOSES ONLY

LEARJET 20 SERIES  PILOT TRAINING MANUAL

FlightSafety

international

NORMAL OUTFLOW INTO

NOSE COMPARTMENT

CABIN ALTITUDE

PRESSURE LIMITER

CABIN PRESSURE

RELIEF VALVE

CABIN AIR EXHAUST

CONTROL VALVE

UP

ALT

DN

ALT

NORMAL
STATIC SOURCE

ALTERNATE
STATIC SOURCE

CABIN ALTITUDE
EMERGENCY SWITCH

CONTROL PRESSURE

CABIN PRESSURE

LEGEND

STATIC PRESSURE

Figure 12A-7.

Outflow Valve (Typical)

Summary of Contents for 20 Series

Page 1: ...ernational LEARJET 20 SERIES PILOT TRAINING MANUAL VOLUME 2 AIRCRAFT SYSTEMS SECOND EDITION FlightSafety International Inc Marine Air Terminal LaGuardia Airport Flushing New York 11371 718 565 4100 www flightsafety com ...

Page 2: ...rning centers Wichita Learning Center Two Learjet Way Wichita KS 67209 800 491 9807 Fax 316 943 0314 Tucson Learning Center 1071 E Aero Park Blvd Tucson AZ 85706 800 203 5627 Fax 520 918 7111 Copyright 2005 by FlightSafety International Inc All rights reserved Printed in the United States of America ...

Page 3: ...CONSISTS OF THE FOLLOWING Zero in this column indicates an original page LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international LEP 1 Revision 01 FOR TRAINING PURPOSES ONLY Page Revision No No Cover 0 Copyright 0 LEP 1 01 LEP 2 0 i ii 0 iii 01 iv 0 1 i 1 18 0 2 i 2 18 0 2A i 2A 24 0 3 i 3 10 0 4 i 4 6 0 5 i 0 5 ii 5 iii 01 5 iv 5 20 0 5A i 5A 8 0 5A 9 01 5A 10 5A 20 0 6 1 0 7 i 7 22 0 ...

Page 4: ...ng it contained then current information In the event of conflict between data provided herein and that in publications issued by the manufacturer or the FAA that of the manufacturer or the FAA shall take precedence We at FlightSafety want you to have the best training possible We welcome any sugges tions you might have for improving this manual or any other aspect of our training program FOR TRAI...

Page 5: ...T Chapter 7 POWERPLANT Chapter 8 FIRE PROTECTION Chapter 9 PNEUMATICS Chapter 10 ICE AND RAIN PROTECTION Chapter 10A ICE AND RAIN PROTECTION Chapter 11 AIR CONDITIONING Chapter 12 PRESSURIZATION Chapter 12A PRESSURIZATION Chapter 13 HYDRAULIC POWER SYSTEMS Chapter 14 LANDING GEAR AND BRAKES Chapter 15 FLIGHT CONTROLS Chapter 16 AVIONICS Chapter 17 MISCELLANEOUS SYSTEMS WALKAROUND APPENDIX ANNUNCIA...

Page 6: ...ms 1 16 Lighting 1 16 Fuel System 1 16 Powerplant 1 16 Ice and Rain protection 1 17 Air Conditioning and Pressurization 1 17 Hydraulic Power Systems 1 17 Landing Gear and Brakes 1 17 Flight Controls 1 17 Pitot Static System 1 17 Oxygen System 1 18 Static or Lightning Strike Protection 1 18 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 7: ...rior Typical 1 9 1 9 Passenger Crew Door 1 9 1 10 Door Locking Pin Hole 1 10 1 11 Emergency Exit 1 11 1 12 Windshield Typical 1 12 1 13 Passenger Windows Typical 1 13 1 14 Tailcone Entry Door 1 13 1 15 Wing 1 14 1 16 Empennage 1 15 1 17 Static Wicks Typical 1 18 TABLE Table Title Page 1 1 Learjet 20 Series Models and Serialization 1 2 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MAN...

Page 8: ...rplane and gives an overview of the sys tems The Walkaround section also contains a pictorial walkaround of the airplane The Annunciator Panel section located at the back of Volume 2 displays all light in dications and should be folded out for reference while reading this manual GENERAL The Learjet 20 series airplanes are all metal low wing twin engine jet airplanes with re tractable landing gear ...

Page 9: ...d During testing all load bearing members and surfaces demonstrated the capability to carry 90 of the G forces with an adjacent structural compo nent failed The airplane structure consists of fuselage wings and empennage The discussion on the fuselage includes the doors and windows General dimensions are shown in Figure 1 2 1 2 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL Fli...

Page 10: ...LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international 41 FT 43 FT 3 IN 14 FT 8 IN 8 FT 3 IN 34 FT 1 IN 35 FT 7 IN 45 FT 47 FT 7 IN 12 FT 3 IN 12 FT 3 IN MODELS 23 AND 24 ALL MODELS MODEL 25 Figure 1 2 Airplane Dimensions ...

Page 11: ...ghtSafety international A B C MODELS 23 AND 24 MODEL 25 A 27 FT 10 IN 31 FT 3 IN B 34 FT 4 IN 37 FT 6 IN C 31 FT 11 IN 35 FT 1 IN NOTE THE VALUES SHOWN REFLECT NORMAL NOSEWHEEL STEERING SHORTER TURNS CAN BE EFFECTED WITH THE USE OF A TOW BAR Figure 1 3 Airplane Turning Radii ...

Page 12: ...hausts 1 5 FOR TRAINING PURPOSES ONLY 45 30 FT 30 FT WEATHER RADAR OPERATING 12 FT 12 FT 600 F 600 F 150 F 40 FT 40 FT 150 F WEATHER RADAR OPERATING EXHAUST DANGER AREAS SHOWN FOR IDLE RPM VALUES APPROXIMATELY DOUBLE FOR TAKEOFF RPM Figure 1 4 Danger Areas LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 13: ...AME 10 FRAME 13 FRAME 22 FRAME 24 PRESSURIZED SECTION TAILCONE SECTION FUEL SEC FORWARD PRESSURE BULKHEAD AFT PRESSURE BULKHEAD TAILCONE DOOR NOTE MODEL 24E DOES NOT HAVE A FUSELAGE TANK MODELS 23 AND 24 MODEL 25 FRAME 1 FRAME 5 FRAME 10 FRAME 13 FRAME 18 FRAME 22 FRAME 25 FORWARD PRESSURE BULKHEAD AFT PRESSURE BULKHEAD 25C AFT PRESSURE BULKHEAD 25 25B AND D TAILCONE DOOR Figure 1 5 Fuselage Secti...

Page 14: ...ncorporates attachments for the wings tail group engine support pylons and the nose landing gear In addition to the pressurized cockpit and passenger compart ments the fuselage includes the nose wheel well an unpressurized nose compartment and a tailcone compartment used for equipment installation Nose Section The nose of the fuselage Figure 1 6 is formed by the radome Aft of the radome is the nos...

Page 15: ...re and aft and are reversible for a foursome arrangement Optional lateral tracking seats that also move inboard are available Safety belts are in stalled on all seats Figure 1 8 depicts a typ ical cabin interior arrangement Safety belts and shoulder harnesses with self adjusting inertia reels are installed on the pilot and copilot seats The inertia reels allow the shoulder harness to extend or ret...

Page 16: ...elage Figure 1 9 The standard entrance 1 9 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 1 8 Cabin Interior Typical door is 36 inches wide but an optional 24 inch door is available The upper door serves as an emergency exit and the lower door has integral entrance steps Figure 1 9 Passenger Crew Door ...

Page 17: ...ed to the frame when the door is closed This engagement holds the lower door closed while the locking handle is being positioned to the locked position Additionally it prevents the door from falling open as soon as the door handle is opened The latch is re leased by depressing the pawl When closing the doors from the inside close and latch the lower door first Then close the upper door and actuate...

Page 18: ... gaged with its respective microswitch The hooks are not disengaged from the door and fully retracted The door may be unsafe for takeoff A hollow neoprene seal surrounds the door frame the seal has holes to allow the entry of pressurized cabin air forming a positive seal around the door Emergency Exit A hatch near the right rear of the cabin serves as an emergency exit on all Learjet 20 models Fig...

Page 19: ...lot s and copilot s halves and consists of three laminated layers of acrylic plastic The windshield is approximately one inch thick It is impact resistant and was tested against four pound bird strikes at 350 knots Passenger Windows 23 24 24B Models Three large dual pane acrylic plastic win dows are installed in the airplane The right rear window serves as an emergency exit The panes are held apar...

Page 20: ...3 24 24B D F and 24E when installed Frames 22 to 25 Models 25 25B and D Frames 18 to 25 Model 25C which has long range tanks installed Tailcone Section The tailcone section extends aft from the fuel section to the empennage The tailcone entry door Figure 1 14 is located at the bottom of this section On some airplanes the door is hinged at the forward edge and drops down when released by quick rele...

Page 21: ...1 14 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 1 15 Wing ...

Page 22: ...g before flight On airplanes incorporating AMK 83 4 Softflite I and AMK 83 5 Softflite wing mod ifications the vortex generators have been re placed with the following Two rows of boundary layer energizers BLEs on each wing which perform the same function as vortex generators but are more efficient If any are missing MMO is reduced to 0 78 MI A full chord fence on each wing in board of the aileron...

Page 23: ... strobe lights and a recognition light A second recognition light and wing ice inspection light are avail able as options The glareshield warning light system consists of three horizontal rows of red amber and green lights see Annunciator Panel sec tion which alert the pilots to various malfunc tions or switch positions They are located on the center portion of the glareshield just above the cente...

Page 24: ... pressuriza tion while airborne HYDRAULIC POWER SYSTEMS The hydraulic system supplies pressure for the operation of the landing gear gear doors brakes flaps spoilers and thrust reversers if installed A single reservoir supplies fluid to the two engine driven pumps through the hy draulic shutoff valves An electric auxiliary pump in the tailcone is used for hydraulic pressure on the ground when the ...

Page 25: ...ssure for operation of the cabin safety valve OXYGEN SYSTEM The oxygen system consists of the crew and passenger distribution systems connected to a high pressure oxygen storage cylinder lo cated in either the nose compartment or the dorsal fin of the vertical stabilizer The flight crew is provided with pressure demand or di luter demand masks Constant flow masks are provided for the passengers Th...

Page 26: ...Emergency Battery System 2 4 Generators and Regulators 2 6 Ground Power 2 7 Circuit Components 2 8 Distribution 2 11 AC POWER 2 14 Inverters 2 14 Controls 2 14 Indicators 2 14 AC Operation 2 14 Distribution 2 15 QUESTIONS 2 16 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 27: ...5 2 5 Generator Cooling Scoop 2 6 2 6 Generator Switches 2 7 2 7 DC Ammeters 2 7 2 8 Ground Power Receptacle 2 7 2 9 Pilot s Circuit Breaker Panel Typical 2 9 2 10 Copilot s Circuit Breaker Panel Typical 2 10 2 11 DC Power Distribution SNs 24 260 264 and Subsequent and 25 090 103 and Subsequent 2 12 2 12 DC Power Distribution SNs 24 230 through 259 261 through 263 25 061 through 089 and 091 throug...

Page 28: ...tery and gener ator switches turned off The hot wired items that are connected to the batteries are Left stall warning Cabin door motor Entry lights Right stall warning Firewall shutoff valve warning lights pinhead CHAPTER 2 ELECTRICAL POWER SYSTEMS 2 1 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international INTRODUCTION This chapter covers the electrical powe...

Page 29: ...t and 25 236 and subsequent Nickel cadmium batteries are optional Because of the poor regulation of most ground power units it is not recommended that either nicad or lead acid batteries be charged in the airplane Should it become absolutely neces sary to charge a nicad battery in the airplane the battery voltage must not be less than 20 5 volts and the temperature must be less than 100 F 37 8 C A...

Page 30: ...ect the bat tery bus to the battery charging bus via the bat tery relay This allows charging of the battery from the generators or provides battery and GPU power to the airplane systems The bat tery switch when in ON provides a ground to the battery relay When the battery switch is in ON battery volt age is indicated on the DC voltmeter if no other power source is connected to the battery charging...

Page 31: ... on the pilot s instrument panel If air plane power is lost the emergency battery provides DC 115 VAC and 4 6 VAC power through a self contained inverter The emer gency attitude indicator is powered and illu minated with AC power and the emergency battery indicator light and the gear flaps and spoilers are powered with DC power Some air planes have an emergency communications radio wired to the em...

Page 32: ...UAL FlightSafety international EMERGENCY BATTERY CB 28 VDC INPUT BATTERY OUTPUT VDC INVERTER EMERGENCY BATTERY VDC INPUT ATTITUDE GYRO 115 VAC OUTPUT 4 6 VAC OUTPUT RH ESS DC BUS INPUT GEARS FLAPS SPOILERS AUX COMM Figure 2 4 Emergency Battery No 1 Switch and Schematic ...

Page 33: ...o zero Controls The generator switches Figure 2 6 located on the lower portion of the instrument panel have three positions labeled OFF START and GEN OFF position deenergizes the starter generator START position energizes the engine start cycle GEN position supplies voltage to the generator relay and through the voltage regulator to the field windings en ergizing the generator to supply power to t...

Page 34: ...25 070 through 102 excluding 090 To charge both batteries using external power plug in the GPU and regulate the voltage out put to 28VDC Ground power unit output should be limited to a maximum of 1 000 amperes Airplanes with Dual Battery Switches SNs 24 260 264 and Subsequent and 25 090 103 and Subsequent To charge both batteries using external power turn on both battery switches Plug in the GPU a...

Page 35: ...l power relays starter relays generator relays and inverter re lays are used to connect control the power cir cuits Instrument panel switches complete the control circuits and operate the relays Relays are also used to connect the power circuits to the left and right main DC buses Overload Sensors The DC overload sensors are located in the tail cone An overload control sensor consists of a 70 ampe...

Page 36: ...S WRN HT ARM CONT PRI LCH R EMER STOW IND LTS AUX LCH DOOR ACTR ENT LTS ADF 1 DME 1 L LDG TAXI LT NAV LTS STROBE LTS CAB LTS FREON CONT CAB BLO L ECS VAL NOSE STEER ANTI SKID STEREO SQUAT SW HF COMM EMER LTS HT VAL IND HF COMM ALC PMP AUX CAB HT WING INSP LT L MAIN BUS PRI INV L AC BUS PRI VM PRI DIR GY PRI VERT GY L EPR PRI AFCS RADAR GY FLT DR ATTD FLT DR CMD FLT DR HD NOSE STEER AIR DATA 26 VAC...

Page 37: ...G TAXI LT BCN LTS RAD ALTM ALTM WSHLD HT WING HT L NAC HT R NAC HT STAB HT FUSLG PMP FILL XFER HR MTR ENG SYN TOILET BATT TEMP CLOCK R ECS VAL OVEN INTPH RADAR SOV LTS AUD 2 COMM 2 NAV 2 EMER P TRIM ATC 2 TURN BANK WRN LTS INSTR LTS R PIT HT CAB PRESS MKR BCN SEC AFCS SEC FLT DIR S WRN HT AUX INV ARM CONT PRI LCH L EMER STOW IND LTS AUX LCH R FIRE DET R FIRE EXT R FW SOV R JET PMP VAL R STBY FUS P...

Page 38: ...t for the hot wired items All hot wired items are connected directly to the bat teries The battery bus is connected to the left or right starter through the associated start relay when the respective generator switch is placed in the START position Battery Charging Bus The battery charging bus is located in the cur rent limiter panel in the tailcone It distributes power from the batteries or GPU t...

Page 39: ...XT POWER OVERVOLTAGE L STARTER GEN R STARTER GEN DC VOLTS AMPS AMPS 70 A 60 A 60 A 50 A 40 A 275A 40 A 70 A 60 A 50 A 275 A 275 A START RELAY START RELAY L BATTERY RELAY R BATTERY RELAY R BATTERY BUS L BATTERY BUS 10 A 10 A 20 A 20 A 100A 100A 50 A 20 A FREON SYS STAB HEAT L NACELLE HEAT R NACELLE HEAT OFF OFF GEN FIELD COIL GEN FIELD COIL ON ON 33 2 VDC SNs 25 368 AND SUBSEQUENT AND AIRPLANES WIT...

Page 40: ...DC VOLTS AMPS AMPS 70 A 60 A 60 A 50 A 40 A 275A 40 A 70 A 60 A 50 A 275 A 275 A START RELAY START RELAY R BATTERY BUS L BATTERY BUS 10 A 10 A 20 A 20 A OFF ON 100A 100A 50 A 20 A FREON SYS STAB HEAT L NACELLE HEAT R NACELLE HEAT GEN FIELD COIL GEN FIELD COIL 33 2 VDC AIRPLANES WITH AMK 85 1 BATTERY RELAY Figure 2 12 DC Power Distribution SNs 24 230 through 259 261 through 263 25 061 through 089 a...

Page 41: ...d If an inverter fails its respective warning light illuminates On SNs 24 230 through 277 25 070 through 25 134 and 25 136 through 140 turning off the inverter switch extinguishes the inverter fail light On SNs 24 278 and subsequent and 25 135 and 141 and subsequent if the inverter fails and the switch is turned to OFF the PRI INV and SEC INV fail lights remain illuminated If the auxiliary inverte...

Page 42: ... BOX TRANS SECONDARY INVERTER AUX INVERTER PRIMARY INVERTER L PWR BUS R PWR BUS R ESS L GEN BUS R GEN BUS BAT CHG BUS L GEN R GEN AC VOLTS 60 A L AC BUS CB R AC BUS CB L AUX AC BUS CB R AUX AC BUS CB AUX INV PRI SEC SW L BUS R BUS POWER RELAY POWER RELAY POWER RELAY AUX INV CB SEC INV SW SEC INV CB PRI INV SW PRI INV CB AUX INV ON OFF SW 60 A 60 A 275 A 275 A BATTERY POWER GENERATOR POWER LEGEND G...

Page 43: ...r rent produced by its respective generator The DC voltmeter indicates A Voltage on the battery bus B Voltage on the essential bus C Voltage on the main bus D Voltage on the battery charging bus 5 The maximum voltage red line value on the DC voltmeter is A 24 VDC B 28 VDC C 35 VDC D 33 2 VDC 6 The maximum red line amperage on the ammeter is A 400 amperes B 600 amperes C 800 amperes D 1 000 amperes...

Page 44: ...formers aft of the pilot and copilot circuit breaker panels 13 The inverters for your particular airplane are located A In the nose compartment B Beneath the divan seat C In the tailcone D Behind the copilot 14 An inverter failure is indicated by A Lack of AC voltage B Lack of AC cycles C An illuminated red fail light with the inverter switch in ON D Red flags on the instruments supplied by the re...

Page 45: ...enerators 2A 4 Circuit Components 2A 5 Distribution 2A 14 Ground Power 2A 17 AC POWER 2A 17 Inverters 2A 17 Controls 2A 18 Indicators 2A 20 Operation 2A 20 Emergency Modes 2A 21 Emergency Battery System 2A 21 QUESTIONS 2A 24 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 46: ...ough 24 199 and 25 025 through 25 034 2A 12 2A 13 Circuit Breaker Panels SNs 24 200 and Subsequent and 25 035 and Subsequent 2A 13 2A 14 DC Power Distribution SNs 23 003 through 24 189 and 25 003 through 25 029 2A 14 2A 15 DC Power Distribution SNs 24 190 through 24 229 2A 15 and 25 030 through 25 064 except 25 061 2A 15 2A 16 External Power Receptacle 2A 17 2A 17 AC Power Distribution SNs 23 003 ...

Page 47: ...nverters located in the tailcone GENERAL The electrical system incorporates a multiple bus system for power distribution The system is interconnected by relays current limiters overload sensors and circuit breakers which au tomatically react to isolate a malfunctioning bus Manual isolation is also possible by open ing the appropriate circuit beakers It is possi ble to power the entire DC and AC el...

Page 48: ...a stainless steel case Charging nicad batteries with a GPU is not recom mended but if absolutely necessary the fol lowing Maintenance Manual restrictions should be observed Battery voltage must not be less than 20 5 volts no load Initial battery temperature must not ex ceed 100ºF 37 8ºC The GPU must be precisely regulated to 28 0 5 volts 1 000 amperes maximum Voltage and battery temperature must b...

Page 49: ...tes the voltage on the battery charging bus from the highest volt age input batteries generator or GPU Airplane generators and GPUs normally pro duce a higher voltage than the batteries there fore when either of these is powering the battery charging bus battery voltage can no longer be read Nickel cadmium batteries are equipped with an overheat warning light sys tem and some airplanes have batter...

Page 50: ...er varying engine speeds and load conditions The voltage regulator is factory adjusted and no regulator adjustment is allowed Controls Two starter generator switches Figure 2A 4 are installed on the switch panel Each three position switch is marked GEN OFF START Moving the starter generator switch to GEN allows the generator relays to energize and complete three circuits a circuit for 28 VDC to th...

Page 51: ...has blown it must be re placed Current limiters are used to provide power to certain systems to back up circuit breakers and to interconnect buses Relays Relays are used at numerous places through out the electrical distribution system partic ularly in circuits with heavy electrical loads The relays function as remote switches to make or break power circuits This arrange ment allows the control ci...

Page 52: ...INDSHIELD DE ICE ROLL INST NAV CABIN PITOT HEAT MAIN DC POWER NACELLE HEAT FLOOD BCN L R NAC ICE DETECT CABIN PRESS L R L L BUS TIE R R MIC PHONE VOL PRIMARY 2 5 2 2 10 2 2 2 2 2 10 2 2 2 2 10 2 7 2 2 2 2 2 2 2 2 2 2 2 5 10 10 10 10 10 10 2 2 2 2 2 2 10 10 10 10 10 10 10 2 IGN START OIL TEMP L R L R L R 10 15 15 10 45 45 50 45 45 2 7 7 2 2 2 2 2 2 2 2 2 5 7 7 7 7 2 2 2 7 2 2 7 2 7 7 7 7 7 15 15 10...

Page 53: ... TRIM RADAR AC DC VOLTMETER DOOR ACTUATOR FREON CONTROL CABIN BLOWER LEFT RIGHT STALL WARN TAXI L R RADAR DC OVER VOLTAGE LOCKOUT COPILOT GYROS RMI SECONDARY ATT CARD POINTER GS NAV COMM AUDIO ADF ATC MKR BCN AIR IGN TURN BANK DME EMERG PWR DE FOG RAT L R L R WARN LIGHTS WARN LIGHTS GEAR FLAPS OXYGEN VALVE ANTI SKID L STDBY PUMP L MOTIVE VALVE FUS PUMP FILL XFER R MOTIVE VALVE R STDBY PUMP IGN STA...

Page 54: ... 25 155 AIRPLANES SNs 24 156 THROUGH 24 169 AIRPLANES SNs 24 144 THROUGH 24 169 AIRPLANES 24 130 THROUGH 24 169 AUDIO LEFT PRIMARY RIGHT SECONDARY COMM NAV NAV COMM AUDIO GS ATC DME MKR BCN ADF GS TURN BANK AFCS DAMPER WARN LIGHTS WARN LIGHTS TAB FLAP POSITION TURN BANK FIRE DETECT FIREWALL SHUTOFF ENG FIRE EXT ENG FIRE EXT FIREWALL SHUTOFF FIRE DETECT NACELLE HEAT PITOT HEAT JET PUMP VALVE JET PU...

Page 55: ...E DETECT FIREWALL SHUTOFF ENG FIRE EXT ENG FIRE EXT FIREWALL SHUTOFF FIRE DETECT NACELLE HEAT PITOT HEAT JET PUMP VALVE JET PUMP VALVE PITOT HEAT STALL WARN HEAT STALL WARN HEAT NACELLE HEAT FUEL QTY XFER FILL STDBY PUMP STDBY PUMP FUS PUMP FUEL FLOW OIL TEMP INSTR LIGHTS NAV FLOOD BEACON IGN START ANTI SKID DE FOG AIR BLEED OXY VALVE MAX CABIN AIRFLOW ALCOHOL PUMP EMER PITCH TRIM PITCH TRIM TAB R...

Page 56: ... L L BUS TIE MAIN DC POWER R R WING ANTI ICE AIR IGN AIR IGN LIGHTS SPOILER GEAR FLAPS NOSE STEER L R STALL WARN AUDIO LEFT PRIMARY RIGHT SECONDARY COMM NAV NAV COMM AUDIO GS ATC DME MKR BCN ADF GS TURN BANK AFCS DAMPER WARN LIGHTS WARN LIGHTS TAB FLAP POSITION TURN BANK FIRE DETECT FIREWALL SHUTOFF ENG FIRE EXT ENG FIRE EXT FIREWALL SHUTOFF FIRE DETECT NACELLE HEAT PITOT HEAT JET PUMP VALVE JET P...

Page 57: ... PITCH TRIM PITCH TRIM TAB ROLL YAW BAT BUS SHUTOFF VALVE LT CABIN DUMP SPOILER GEAR FLAPS NOSE STEER L R STALL WARN L L BUS TIE MAIN DC POWER R R WINGS ANTI ICE AIR IGN AIR IGN LIGHTS 115 VAC 115 VAC PRI VOLT METER PILOT S VERT PILOT S DIRECT RADAR GYRO O AFCS NOSE STEER CABIN PRESS RMI L EPR L OIL PRESS 26 VAC 26 VAC SEC VOLT METER COPILOT VERT COPILOT DIRECT RADAR AFCS R EPR TONE GEN R OIL PRES...

Page 58: ...SHUTOFF VALVE LT CABIN DUMP SPOILER GEAR FLAPS NOSE STEER L R STALL WARN L L BUS TIE MAIN DC POWER R R WINGS ANTI ICE AIR IGN AIR IGN LIGHTS AUDIO LEFT PRIMARY RIGHT SECONDARY COMM NAV NAV COMM AUDIO GS ATC DME MKR BCN ADF GS TURN BANK AFCS DAMPER WARN LIGHTS WARN LIGHTS TAB FLAP POSITION TURN BANK FIRE DETECT FIREWALL SHUTOFF ENG FIRE EXT ENG FIRE EXT FIREWALL SHUTOFF FIRE DETECT NACELLE HEAT PIT...

Page 59: ... DC POWER RIGHT BUS RIGHT IGN START GEN LEFT BUS LEFT IGN START GEN TAB FLAP POSITION LIGHTS BATTERY SHUTOFF VAL LTS BUS EMER P TRIM PITCH ANTI SKID ROLL YAW NORMAL TRIM 115 VAC 115 VAC PRI VOLT METER PILOT S VERT PILOT S DIRECT RADAR GYRO O AFCS NOSE STEER CABIN PRESS L EPR RAM L OIL PRESS 26 VAC 26 VAC SEC VOLT METER COPILOT VERT COPILOT DIRECT RADAR AFCS TONE GEN R EPR R OIL PRESS COPILOT S SID...

Page 60: ...gle system but it is really separate systems in terconnected by a series of current limiters and circuit breakers Figures 2A 14 and 2A 15 illus trate power distribution It is possible to power almost all DC electrical equipment from one generator through the interconnected buses or only certain buses by operation of the bus and or bus tie circuit breakers Starting with SNs 24 130 through 24 229 an...

Page 61: ... the batteries With the battery switch in OFF the generators sup ply power to all airplane equipment except the batteries and hot wired items LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 2A 15 DC Power Distribution SNs 24 190 through 24 229 and 25 030 through 25 064 except 25 061 AMMETER AMMETER RH GEN DC VOLTMETER OVERLOAD SENSOR OVERLOAD SENSOR LH GEN RH BATTERY LH B...

Page 62: ...he Freon air conditioner and auxil iary heater until a GPU is connected or a gen erator is on and operating Generator Buses The left and right generator buses are in the current limiter panel in the tailcone The gen erator buses may be powered by the battery charging bus or by the output of the respective generator The 275 ampere current limiters connect the generator buses to the battery charging...

Page 63: ...3 through 24 129 Two JET solid state static inverters located in the tail compartment provide 115 VAC 400 Hz single phase power Figure 2A 17 Through a separate stepdown transformer 26 VAC power is also provided Each inverter is rated at 750 VA During normal operation the main inverter through the closed AC bus tie circuit breaker operates all AC powered equip ment except the radar When the radar i...

Page 64: ... 229 and 25 003 through 25 064 Three ON OFF inverter switches for the pri mary secondary and standby inverters are lo cated on the switch panel 2A 18 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 2A 18 AC Power Distribution SNs 24 130 through 24 180 and 25 003 through 25 024 PRI INVERTER STDBY INVERTER SEC INVERTER DC PWR L GEN BUS DC PWR R GE...

Page 65: ...INVERTER POWER RELAY SEC INVERTER POWER RELAY STDBY INVERTER POWER RELAY 400VA 400VA 750VA TO INDICATOR LIGHT TO INDICATOR LIGHT TO INDICATOR LIGHT 115 VAC 115 VAC 115 VAC RADAR RELAY 115 VAC 26 VAC 26 VAC AC SWITCHING 115 VAC 115 VAC 26 VAC 26 VAC 26 VAC PRI VOLTMETER PILOT VERT PILOT DIRECT RADAR GYRO AFCS NOSE STEER CABIN PRESS RMI EPR L OIL PRESS ANTI SKID TEST RADAR SEC VOLTMETER COPILOT VERT...

Page 66: ...phase detection The secondary bus powers the No 2 vertisyn and directisyn nosewheel steering cabin pressurization and sometimes fuel quantity Stepdown Transformers The stepdown transformers located on the forward side of frame 28 reduce a portion of the 115 VAC to 26 VAC The 26 VAC is used for the antiskid test SNs 24 112 and subse quent oil pressure gages EPR gages and fuel flow on SNs 23 003 thr...

Page 67: ...airplanes SNs 24 100 through 24 129 have an auxiliary battery in stalled On all other airplanes an optional emergency battery is available Auxiliary Battery System SNs 24 100 through 24 129 Auxiliary battery power Figure 2A 20 is supplied by a 2 6 ampere hour 25 volt nickel cadmium dry cell battery The battery in stalled beneath the divan seat consists of a steel case containing 20 cells and a 50 ...

Page 68: ...os Emergency Operation Under an emergency mode of operation the auxiliary battery through a diode network provides power to the pilot s audio panel ADF transceiver nosewheel steering relay wheel master button directional and attitude gyros trim systems copilot s map light etc The momentary switch must be held to the ON position when power is needed to operate the gear flaps and spoilers With all t...

Page 69: ...AL FlightSafety international GEAR FLAPS SPOILERS AUX COMM EMERGENCY BATTERY C B 28 VDC 25 VDC 25 VDC INPUT 115 VAC OUTPUT 4 6 VAC OUTPUT ON OFF BATTERY INV INSTRUMENT LIGHTS FEEDER BUS INPUT ATTITUDE GYRO INPUT POWER INTERNAL LIGHTS Figure 2A 21 Emergency Battery System ...

Page 70: ...put that may be used for an engine start is A 400 amperes B 600 amperes C 1 000 amperes D 1 100 amperes 4 Generator current flow in amperes is measured from the A Battery charging bus B Generator field coil C Generator bus D Feeder bus 5 The DC voltmeter draws its reading from the A Battery bus B Battery charging bus C Generator bus D Feeder bus 2A 24 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES P...

Page 71: ... 3 Emergency Lighting 3 4 EXTERIOR LIGHTING 3 4 General 3 4 Landing Taxi Lights 3 6 Recognition Lights Not Installed on All Airplanes 3 7 Navigation Lights 3 7 Anticollision Lights 3 8 Wing Inspection Light Optional 3 8 QUESTIONS 3 9 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 72: ...isory Lights and Control 3 3 3 5 Emergency Lights Switch 3 4 3 6 Exterior Lighting Locations 3 5 3 7 Exterior Lighting Switches 3 6 3 8 Landing Taxi Lights 3 6 3 9 Recognition Light 3 7 3 10 Strobe and Navigation Lights 3 7 3 11 Anticollision Lights 3 8 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 73: ...ERAL Cockpit lighting consists of the instrument lights floodlight panel lighting and map lights all adjustable for intensity with rheo stat controls The panel lighting illuminates the lettering on the various switch panels pedestal and circuit breaker panels Side panel map lights are installed for the pilot s convenience Cabin lighting consists of upper center panel lights door entry lights bagga...

Page 74: ...he light dimmer assemblies are lo cated in the nose compartment Instrument Panel Floodlights The pilot s and copilot s floodlights located under the glareshield are individually con trolled by separate on off rheostat switches The pilot s controls on the left side and the copilot s on the right side of the cockpit control separate sections of the floodlights The lights are powered through the INST...

Page 75: ...Smoking Fasten Seat Belt Sign The lights are located on the aft side of the left service cabinet Figure 3 4 and are controlled by a switch on the pedestal In addition to en ergizing the lights the control switch applies 28 VDC to the tone generator which produces an audible tone through the aft cabin speaker The lights are powered through the CAB LTS circuit breaker Baggage Compartment Lights Two ...

Page 76: ...unction for the system and for automatic illumination of the emergency lights in the event of an interruption of normal DC elec trical power The switch has three positions TEST ARM and DISARM Setting the switch to TEST simulates a failure of normal DC elec trical power and illuminates the upper cabin entry door light the emergency exit light and the cabin overhead lights Setting the switch to ARM ...

Page 77: ...G MANUAL FlightSafety international NAVIGATION LIGHT ANTICOLLISION LIGHT ANTICOLLISION LIGHT WING INSPECTION LIGHT STROBE LIGHT STROBE LIGHT LANDING TAXI LIGHTS RECOGNITION LIGHT NAVIGATION LIGHT NAVIGATION LIGHT STROBE LIGHT Figure 3 6 Exterior Lighting Locations ...

Page 78: ...and right main buses respectively Setting the L or R LDG LT switch to TAXI LT closes a relay which shunts DC power from the respective generator bus through a resistor which limits current to the lamp element Moving the switch to LDG LT closes a second relay allowing current flow to bypass the re sistor thereby increasing the brightness of the lamp The 20 amp current limiters protect the 3 6 FOR T...

Page 79: ...s a control relay and connects power through a 30 ampere current limiter to each light STROBE LIGHTS The strobe light system consists of one strobe light mounted inside each wingtip navigation light fixture Figure 3 10 and one in the tail a power supply for each strobe a STROBE switch a DC STROBE LTS circuit breaker and a timing circuit module that causes the strobes to flash Each power supply is ...

Page 80: ...he right side of the fuselage adjacent to the lower forward corner of the emergency exit window This light is de signed to illuminate the leading edge of the right wing The light may be installed as part of the emergency lighting system The WING INSPECTION control switch is located on the emergency lighting panel Models 23 24 24B and 25 airplanes vary to some extent in the location of switches and...

Page 81: ... entrance door threshold C Left forward service cabinet D Light assembly 4 The lights that are illuminated by the emergency lighting system are the A Instrument panel floodlights B Cabin overhead lights wing inspec tion light and emergency exit lights C Navigation lights D Strobe lights 5 If installed the emergency lighting switch position used during normal operation is A DISARM B ARM C TEST D EM...

Page 82: ...e INTRODUCTION 4 1 GENERAL 4 1 GLARESHIELD WARNING LIGHTS 4 2 TEST FUNCTION 4 2 INTENSITY CONTROL 4 2 BULB CHANGE 4 2 ILLUMINATION CAUSES 4 2 QUESTIONS 4 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 83: ...ILLUSTRATION Figure Title Page 4 1 Test Switch 4 2 TABLE Table Title Page 4 1 Annunciator Illumination Causes 4 3 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 84: ...ction which alert the pilots to various mal functions or switch positions The lights are located on the center portion of the glareshield just above the engine gages These lights are referred to as the glareshield warning lights Provision is made to test all warning system lights with a switch located just beneath the glareshield lights panel Other annunciator lights are located on the instrument ...

Page 85: ...on The gear lights are also con trolled by a rheostat on the landing gear panel Photoelectric cells inboard of each FIRE switch automatically dim the lights on the glareshield to a level corresponding to exist ing light conditions in the cockpit or to a min imum preset level for a totally dark cockpit On some airplanes there is also a rheostat under the left side of the glareshield that con trols ...

Page 86: ... is more than 215 F The alcohol system has failed or the alcohol tank is empty Either or both spoilers are not down and locked The entrance door is improperly closed or malfunctioning Either or both fuel filters are bypassing fuel Bleed air pressure to the engine s front frame is less than 5 psi The engine sync system is turned ON with the nose gear extended One or both batteries tempera ture is 1...

Page 87: ...locked There is an antiskid failure in the associated brake The green lights indicate anti skid generator operative if traveling faster than 5 mph The white light indicates a valid test of the antiskid system At or below altitude set in radio altimeter Air ignition operating Air igni tion switch is on or system is in start cycle FUEL XFLO Crossflow valve is open L LO OIL R LO OIL Indicated engine ...

Page 88: ...hutting the represented system off 2 An illuminated glareshield warning light suddenly extinguishes indicating A Five minutes have passed B The malfunction no longer exists C Three minutes have passed D The test switch has been reset 3 The glareshield annunciator light intensity is adjusted A Automatically by a photoelectric cell B By depressing the test switch C By depressing each individual caps...

Page 89: ...G SYSTEMS 5 4 Fuel Quantity Indicating System Low Fuel Warning 5 4 Fuel Flow Indicating System 5 7 FUEL DISTRIBUTION 5 8 General 5 8 Boost Pumps 5 8 Motive Flow Fuel and Jet Pumps 5 8 Filters 5 9 Main Fuel Shutoff Valves 5 9 Low Fuel Pressure Warning Lights 5 9 Pressure Relief Valves 5 10 Fuel Drain Valves 5 10 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety interna...

Page 90: ...2 Fuselage Fuel Fill Transfer Operations 5 13 TIP TANK FUEL JETTISON SYSTEM OPTIONAL 5 14 FUEL SERVICING 5 14 General 5 14 Approved Fuels 5 16 Fuel Density Adjustments 5 16 Aviation Gasoline 5 16 Anti Icing Additive 5 17 Refueling 5 17 OPERATIONAL CONSIDERATIONS 5 17 QUESTIONS 5 19 Revision 01 5 ii FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 91: ...5 4 Fuel Control Panels 5 6 5 5 Fuel Flow Indicators 5 7 5 6 Jet Pump Schematic 5 8 5 7 Fuel Drain Locations 5 10 5 8 Airplane Grounding Points 5 15 5 9 Anti icing Blending Apparatus 5 15 5 10 Fuel Density Adjustment 5 16 5 11 Refueling Filler Cap 5 17 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 92: ...ncing Each wing tank contains a jet pump and an electric standby pump to supply fuel to the en gine on the same side Tip tank and fuselage tank fuel must be transferred into the wing tanks by jet pumps and an electric pump respectively A ram air system is used to vent all tanks Drain valves are provided to remove conden sation and contaminants from the low points in the fuel tanks and to drain the...

Page 93: ...SERIES AIRPLANES 25 SERIES AIRPLANES CROSSFLOW VALVE WING PRESS SW TRANSFER VALVE FUSELAGE TANK NOT INSTALLED ON LR 24E TRANSFER LINE EMPTY LIGHT PRESSURE SWITCH MOTIVE FLOW VALVE MOTIVE FLOW FUEL MODELS 24D E F AND 25B D F P P P P P TO SUMP FUEL JETTISON SHUTOFF VALVE LOW FUEL PRESSURE SWITCH DIFFERENTIAL PRESSURE SWITCH FUEL SHUTOFF VALVE 75 PSI RELIEF VALVE CROSSFLOW VALVE WING PRESS SW TRANSFE...

Page 94: ...re airplane fuel system WING TANKS Each wing tank extends from the airplane cen terline to the tip tank and holds 1 160 pounds of usable fuel Areas which are not part of the wing fuel cell are the main landing gear wheel well the leading edge forward of spar 1 wing heat area and the trailing edge between spars 7 and 8 flap spoiler and aileron areas The 2 5 wing dihedral makes the inboard por tions...

Page 95: ...fuselage just aft of the main landing gear collects any fuel which might enter the vent lines during refueling A vent drain valve permits draining of the sump which must be accomplished prior to every flight to ensure that the vent line to the fuse lage tank is unobstructed FUEL INDICATING SYSTEMS FUEL QUANTITY INDICATING SYSTEM LOW FUEL WARNING The fuel quantity indicating system includes an indi...

Page 96: ...lightSafety international WING VENT FLOAT VALVE VACUUM RELIEF FUEL VENT DRAIN OVERBOARD DRAIN FLAME ARRESTER RAM AIR SCOOP FLOAT VALVE TYPICAL PRESSURE RELIEF VACUUM RELIEF TO AMBIENT VACUUM RELIEF VALVE 1 5 PSI RELIEF VALVE 1 0 PSI RELIEF VALVE Figure 5 3 Fuel Vent System ...

Page 97: ...MPTY XFER FILL FUS TANK 25B D MODELS CLOSE JET PUMPS STANDBY PUMPS 0 0 0 0 0 1 2 3 4 5 6 FUEL QUANTITY LBS 1000 L TIP 1235 L WING 1160 R WING 1160 R TIP 1235 TOTAL 4790 LBS L R ON L R ON OPEN CROSS FLOW MODEL 24E MODELS EQUIPPED WITH RECOGNITION LIGHT 25B D MODELS WITH RECOGNITION LIGHT 25B D MODELS WITH FUEL JETTISON 25B D MODELS WITH RECOGNITION LIGHT AND FUEL JETTISON L TIP 1235 L WING 1160 R W...

Page 98: ... See Annunciator Panel section When flying with the LOW FUEL light on limit pitch at titude and thrust to the minimum required When the fuel quantity gage indicates 600 pounds or less remaining in either wing tank prolonged noseup attitude of 10º or more may cause fuel to be trapped in the aft area of the wing tank outboard of the wheel well Fuel starvation and engine flameout may occur Reducing p...

Page 99: ...active BOOST PUMPS Submerged DC powered boost pumps are in stalled at three different locations one standby pump in each wing adjacent to the jet pump and one transfer pump in the fuselage tank NOTE Both wing tank standby pumps are deactivated when the XFER FILL switch is in the XFER position The wing tank standby pumps are used For engine start automatically ener gized with starter switch activat...

Page 100: ... ensure against loss of pressure to the engine driven pump NOTE With an engine shut down both the wing and the tip tank jet pumps are inoperative on that side NOTE If a jet pump indicator light remains illuminated after a selection is made the motive flow valve is not in the position selected by the switch The motive flow control valves close auto matically when the GEN START switch is energized a...

Page 101: ...e opposite direction opens at 1 psi to equalize fuel pressure between the wing tanks during crossflow operation FUEL DRAIN VALVES Drain valves are located at low points through out the fuel system for draining condensation or sediment A small amount of fuel should be drained from each valve during the exterior preflight inspection The valves spring loaded to the closed position are located as foll...

Page 102: ...livered to the affected engine driven pump by the operating standby pump on that side Asymmetric power set tings may be used to balance fuel if necessary The above considerations do not apply to sin gle engine operations and normal crossflow operations may be performed as usual TRANSFER VALVE XFER FILL SWITCH NORMAL TRANSFER LINE The fuel transfer line connects the fuselage tank with the crossflow...

Page 103: ...lve open turning either wing standby pump switch on will automatically cause the fuselage valve and crossflow valves to sequence closed NOTE Positioning the XFER FILL switch to XFER while also positioning the FUS VALVE switch to OPEN should be avoided because it will cause both fuselage transfer lines and the cross flow line to be open and the fuselage pump to be energized The result of this actio...

Page 104: ...e opens The fuselage transfer pump is energized The white EMPTY light pressure switch is enabled NOTE As fuselage quantity approaches zero the crew should be alert for steady illumination of the white EMPTY light Failure to position the XFER FILL switch to OFF at that time can cause damage to the transfer pump When the XFER FILL switch is placed in the OFF position The transfer pump is deenergized...

Page 105: ...rough a filler cap in the top of each tip tank Fuel then begins to flow by gravity from the tip tanks into the wing tanks as the tip tanks reach one half full The wing standby pumps fill the fuselage tank when the XFER FILL switch is set to FILL At normal temperatures some water is always in solution dissolved with fuel At high al titudes fuel undergoes a cold soaking process and small amounts of ...

Page 106: ...SES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international MIL I 27686 FUEL ADDITIVE TRIGGER RING HANDLE BLENDER HOSE FUEL NOZZLE Figure 5 9 Anti icing Blending Apparatus Figure 5 8 Airplane Grounding Points ...

Page 107: ...ay be used as an emer gency fuel and mixed in any proportion with the various approved kerosene base fuels Aviation gasoline may not be used in excess of 25 hours between engine overhauls When using any aviation gasoline in the fuel mixture operation is lim ited as follows Do not take off with fuel temperature lower than 54ºC 65ºF Restrict airplane flights to below 15 000 feet Both jet pumps and b...

Page 108: ...standby pumps are used to fill the fuselage tank See Fuel Transfer System this chapter A ground power unit should be used if possible be cause of the requirement to operate the standby pumps Refer to the approved AFM for de tailed refueling procedures Do not completely fill one tank be fore adding fuel to the opposite tank Fill both tanks simultaneously or alternately add 125 gallons 473 2 liters ...

Page 109: ...to supply the engines at altitudes of 25 000 feet or below Do not energize fuselage transfer system when wing and tip tanks are full Do not crossflow with wing jet pump inoperative If the crossflow valve fails to open fuselage fuel gravity flow into the right wing tank left tank on 25C airplanes Minimum fuel temperature for takeoff is Jet B JP 4 54ºC 65ºF Jet A Jet A 1 29ºC 20ºF AVGAS 54ºC 65ºF In...

Page 110: ...Engine start B As a backup for the main jet pumps C Fuselage to wing fuel transfer D Wing to fuselage transfer of fuel 5 The crossflow valve opens A Only when the CROSS FLOW switch is set to OPEN B Only when the CROSS FLOW switch is set to OPEN or the XFER FILL switch is set to XFER C Anytime electrical power is lost D Whenever the CROSS FLOW XFER FILL or FUS VALVE switches are moved from the OFF ...

Page 111: ...turns A Off the fuselage transfer pump B On the fuselage transfer pump C Off the wing standby pumps D On the wing standby pumps 12 When using any aviation gasoline in the fuel mixture operation is limited to the following A Do not take off with the fuel tem perature lower than 54ºC 65ºF B Restrict flights to below 15 000 feet C Both main jet pump switches and both wing standby pump switches must b...

Page 112: ...em Low Fuel Warning 5A 6 Fuel Flow Indicating System 5A 8 FUEL DISTRIBUTION 5A 9 General 5A 9 Boost Pumps 5A 9 Motive Flow Fuel and Jet Pumps 5A 9 Filters and Pressure Switches 5A 10 Main Fuel Shutoff Valves 5A 10 Low Fuel Pressure Warning Lights 5A 10 Pressure Relief Valves 5A 11 Fuel Drain Valves 5A 11 FUEL TRANSFER SYSTEM 5A 12 Crossflow Valve 5A 12 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES ...

Page 113: ...on System Optional 5A 13 FUEL SERVICING 5A 14 General 5A 14 Safety Precautions 5A 14 Approved Fuels and Fuel Density Adjustments 5A 14 Aviation Gasoline 5A 15 Anti icing Additive 5A 15 Refueling 5A 16 Jet Fuel 5A 17 QUESTIONS 5A 18 5A ii FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 114: ...l Vent System 5A 6 5A 5 Fuel Control Panels 5A 7 5A 6 Fuel Flow Indicator 5A 8 5A 7 Jet Pump Schematic 5A 9 5A 8 Fuel Drain Locations 5A 11 5A 9 Airplane Grounding Points 5A 14 5A 10 Fuel Density Adjustment 5A 15 5A 11 Anti ice Additive Blending Apparatus 5A 16 5A 12 Refueling Filler Cap 5A 17 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 115: ...mp and a jet pump installed at the inboard side of each wing fuel tank The total trapped and unusable fuel included in the empty weight is ap proximately 23 gallons An electric boost pump in each tip tank on 23 models without jet pumps is used to transfer all tip tank fuel into the respective wing tank This is primarily for the lower portion of the tank since the top portion of the tank will gravi...

Page 116: ... TANK MAIN FUEL SHUTOFF VALVE LH FUEL FILTER LH ENGINE FUEL QUANTITY GAGE CROSSFLOW VALVE REFUEL LINE TRANSFER VALVE REFUEL VALVE NC FUSELAGE FUEL TANK TO FUEL QUANTITY GAGE FUSELAGE TANK TRANSFER SWITCH SUPPLY LOW PRESSURE FUSELAGE TANK TRANSFER LEGEND FUEL PROBE FILLER CAP ELECTRICAL CHECK VALVE BOOST PUMP FLOAT SWITCH SHUTOFF VALVE PRESSURE SWITCH FUSELAGE TANK FILL SNs 23 015 THROUGH 23 069 Fi...

Page 117: ...the engine is shut down Figures 5A 1 through 5A 3 illustrate the early series Learjet fuel system 5A 3 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international EMPTY LOW FUEL CROSS FLOW FUS FILL ON OFF EMPTY FUEL FILTER L FUEL PRESS FUS FULL TIP TANK EMPTY LIGHT LH CROSSFLOW VALVE LH TIP TANK LH WING TANK FUSELAGE TANK TRANSFER SWITCH TRANSFER VALVE FUEL FILTER...

Page 118: ... FUEL SHUTOFF VALVE LH TRANSFER VALVE FUEL FILTER LH ENGINE MOTIVE FLOW CONTROL VALVE RELIEF VALVE 0 1 3 4 FUEL FILTER LOW FUEL LH WING TANK LOW FUEL STANDBY PUMP ON LH OFF FILLER CAP CROSSFLOW VALVE SUPPLY LOW PRESSURE HIGH PRESSURE LEGEND EFFECTIVITY FUEL PROBE PRESSURE RELIEF VALVE ELECTRICAL CHECK VALVE TRANSFER FILL 24 AND 24B MODELS AIRPLANES WITHOUT GLARESHIELD LIGHTS 25 SERIES BOOST PUMP F...

Page 119: ...erged in fuel until the tanks are nearly empty NOTE The 23 models without jet pumps have two electric fuel pumps in each wing tank All other Learjets have one electric standby pump and one jet pump in each wing tank Wing ribs and spars act as baffles to minimize fuel shifting Flapper valves located in the wing ribs allow unrestricted inboard flow of fuel and limit outboard flow Two pressure relief...

Page 120: ... except SNs 23 003 through 23 014 see Figures 5A 1 through 5A 3 The six position rotary selector switch en ables the pilot to check the fuel quantity in each of the five tanks and the airplane total fuel quantity The fuel quantity for the posi tion selected is read on the fuel quantity in dicator The quantities printed beside each selector switch position indicate usable fuel capacities in pounds ...

Page 121: ...G 1160 R WING 1160 R TIP 1195 TOTAL 6055 LBS FUS 1305 L R ON L L R R ON OFF FUEL JETTISON OPEN CROSSFLOW FULL OFF EMPTY XFER FILL FUS TANK L DUMP R DUMP 24 AND 24B MODELS 23 MODEL LATE 23 MODEL EARLY 25 MODEL L TIP 1196 L WING 1092 R WING 1092 R TIP 1196 TOTAL 5388 LBS FUS 812 0 0 0 0 L ENG LH ENG RH ENG R ENG STDBY STDBY FULL ON OFF EMPTY TIP TIP FUS FILL MAIN MAIN FUS CROSS FLOW LOW FUEL STDBY S...

Page 122: ...ngle LOW FUEL light see Annunciator Panel section will illuminate when either wing fuel quantity is low When the fuel quantity gage indi cates 600 pounds or less remaining in either wing tank prolonged noseup attitude of 10 or more may cause fuel to be trapped in the aft area of the wing tank outboard of the wheel well Fuel starvation and engine flameout may occur Reducing pitch attitude and thrus...

Page 123: ...ank directs fuel for ward to the wing tanks NOTE On airplanes with electric fuel pumps the standby pumps are hot wired to the battery Airplanes with jet pumps have three electric fuel pumps An electric standby pump in each wing is used for engine start and as a backup pump for the engine supply as well as for crossflow and filling of the fuselage tank The transfer pump in the fuselage tank directs...

Page 124: ...sition selected by the switch FILTERS AND PRESSURE SWITCHES A fuel filter is installed in each engine feed line Should the filters become clogged from ice or contaminants the fuel is allowed to by pass the filters A differential pressure switch installed in each filter assembly signals the cockpit when one or both filters are bypass ing fuel One amber FUEL FILTER annunci ator illuminates when this...

Page 125: ...n gines are shut down by venting fuel overboard FUEL DRAIN VALVES Drain valves are located at low points throughout the fuel system for draining con densation or sediment A small amount of fuel should be drained from each valve dur ing exterior preflight inspection The valves spring loaded to the closed position are lo cated as follows two on each tip tank one for the crossflow valve one for each ...

Page 126: ...del 23 airplanes not incorporating jet pumps when the fuselage transfer FUS switch see Figure 5A 1 is moved to the ON position the fuselage tank transfer valve and the cross flow valve are opened and the fuselage tank pump is energized to pump fuel equally into two wing tanks The fuselage tank EMPTY light see Annunciator Panel section is illuminated when fuel pressure in the transfer line drops be...

Page 127: ...selage tank The fuselage refuel valve is controlled by the FUS FILL switch see Figure 5A 1 Fuel may be pumped from the wings to the fuselage tank using the FUS FILL switch set to FILL This turns on the left wing electric standby boost pump 23 003 through 23 069 or the left and right wing electric standby boost pumps SNs 23 070 through 23 099 In addition the CROSS FLOW switch must be set to OPEN wi...

Page 128: ...tive An indication of this is when an excessive amount of water accumulates in the fuel tank sumps Refer to Section II Normal Operating Procedures of the AFM for checking fuel additive SAFETY PRECAUTIONS The airplane should be fueled only in areas which permit free movement of fire equipment Assure that the fuel truck is grounded to an ap proved grounding source Attach a ground from fuel truck to ...

Page 129: ...s ANTI ICING ADDITIVE Anti icing additive conforming to MIL I 27686 must be added to all fuels for Learjet operations The additive concentration shall be a minimum of 06 to a maximum of 15 by volume Assure that the additive is directed into the flowing fuel stream and that the additive flow is started after fuel flow starts and is stopped before fuel flow stops Figure 5A 11 Due to the chemical com...

Page 130: ...ternately add 125 gallons 472 3 liters of fuel to each tip tank until the desired amount is obtained On Model 23 the limits are 150 gallons 567 8 liters The fuselage tank may be filled after landing or while taxiing to the parking area to conserve battery power If not accomplished in the above manner a GPU should be used When the airplane is full of fuel the airplane s CG is near the aft limit and...

Page 131: ...iven fuel pumps suction feed sufficient fuel to supply the engines at altitudes of 25 000 feet or below Do not energize fuselage transfer system when wing and tip tank are full Do not crossflow with wing jet pump inoperative Do not transfer fuel if crossflow valve fails to open Maximum tip tank fuel for landing is 800 pounds in each tip for models 24 24B and 25 and 640 pounds for model 23 A minimu...

Page 132: ... remain in either wing 4 The wing standby pumps are used for all of the following functions except A Engine start B As a backup for the main jet pumps C Fuselage to wing fuel transfer D Wing to fuselage transfer of fuel 5 The crossflow valve opens A Only when the CROSS FLOW switch is set to OPEN B Only when the CROSS FLOW switch is set to OPEN or the XFER FILL switch is set to XFER C Anytime elect...

Page 133: ...t be on and the pumps must be operating D All the above 12 The Learjet 20 series airplanes require anti icing additive A At all times B Only when temperatures of 37 C and below are forecast C Only for flights above 15 000 feet D Only for flights above FL 290 13 On 23 models without jet pumps tip tank fuel is transferred by A Inline boost pump B Gravity C Jet pumps D Submerged electric boost pumps ...

Page 134: ...This information normally contained in this chapter is not applicable to this particular airplane ...

Page 135: ...ing Principles 7 8 ENGINE SYSTEMS 7 8 General 7 8 Oil System 7 8 Fuel System 7 11 Ignition System 7 13 Air Systems 7 13 ENGINE POWER CONTROL 7 15 General 7 15 Friction Control 7 15 ENGINE INSTRUMENTATION 7 16 General 7 16 Pressure Ratio 7 16 Exhaust Temperature 7 16 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 136: ... Woodward Electronic Synchronizer Optional 7 17 Synchroscope Optional 7 18 THRUST REVERSERS OPTIONAL 7 18 General 7 18 Control and Indication 7 19 Automatic Stow 7 19 Emergency Stow 7 19 DIFFERENCES 7 20 QUESTIONS 7 21 7 ii FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 137: ... 7 7 Oil Servicing Access 7 8 7 8 Center Instrument Panel 7 9 7 9 Oil System Schematic 7 10 7 10 Flow Divider and Nozzle 7 12 7 11 Fuel System Schematic 7 14 7 12 Center Switch Panel 7 13 7 13 Center Console 7 16 7 14 ENG SYNC Switch 7 17 7 15 Thrust Reversers 7 18 7 16 Thrust Reverser Control Test and Indicating Panel Typical 7 19 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL...

Page 138: ...ree attachment points Eight thermocouples generate an av erage value of exhaust gas temperature indi cated on the EGT gages in the cockpit An engine driven starter generator is installed on each engine to provide engine starting and furnish DC power to the airplane s electrical system Compressor discharge air bleed air through a mainframe port on each engine is utilized for cabin pressurization an...

Page 139: ...ries engine is a single spool turbojet designed as a power unit for small to medium sized corporate airplanes MAJOR SECTIONS For descriptive purposes the engine Figure 7 1 is divided into seven major sections as follows 1 Front frame 2 Compressor 3 Mainframe 4 Combustion 5 Turbine 6 Exhaust 7 Accessory Front Frame The front frame Figure 7 2 admits air to the compressor directing air to the first s...

Page 140: ...ed by the variable geometry actu ators which utilize high pressure fuel from the engine fuel control unit Compressor The compressor Figure 7 3 is an eight stage axial flow unit consisting of rotors and stators It functions to increase the pressure of the inlet air and direct the airflow rearward The stator casing assembly which surrounds the compressor rotor assembly consists of a com pressor casi...

Page 141: ...s the main structural support of the engine It consists of a frame which houses the power takeoff hous ing and drive assembly and provides a mount for the twelve fuel flow divider fuel nozzles the fuel manifolds two eighth stage air leak age check valves and the gearbox assembly The eighth stage stators and exit guide vanes are mounted on twelve segments dovetailed into a track cut into the front ...

Page 142: ...d around the main frame with a fuel drain valve connecting the sections at the six o clock position The en gine is attached to the pylon by mounting pads on the mainframe 7 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 7 4 Mainframe Section EXIT GUIDE VANES P T O HOUSING SHAFTGEAR DRIVER NO 2 CARBON SEAL SUPPORT NO 2 CARBON SEAL INSULATION B...

Page 143: ...ar to the No 3 bearing support The combustion liner consists of a cowl section a dome section and an outer and inner shell Air enters the combustion dome through swirl cups to support combustion and provide dome cooling Thimble holes direct air into the burn ing area while louvers provide a boundary layer of cool air along the inner surface of the liner The No 3 bearing and carbon seal are at the ...

Page 144: ...on to direct the combustion gases from the engine Exhaust thermocouples and engine pressure ratio EPR probes are mounted on the ex haust cone outer casing Accessory Section The engine accessories are driven through a shaft gear driver splined to the aft end of the compressor drive shaft A bevel gear on the driver shaft engages a gear on a radial drive shaft which transmits power to accessory gearb...

Page 145: ...M General The oil system utilizes a pressurized closed circuit recirculating dry sump system de signed to furnish lubricating and cooling oil to the necessary rotating components during en gine operation After circulating to those parts requiring lubrication it drains to the sumps where it is scavenged by individual elements within the pump and returned to the oil tank Oil Tank The oil is containe...

Page 146: ...ct flow of oil through the unit without filtration Indication Oil pressure is sensed by an AC transmitter and sent to a dual needle gage on the instrument panel Figure 7 8 Oil pressure is also sensed by a pressure switch that will turn on the LO OIL PRES light see Annunciator Panel section if oil pressure is below 5 psi The oil pressure gages must be checked to determine the problem engine NOTE Le...

Page 147: ...ESSOR ROTOR DRIVE SHAFT ACCESSORY DRIVE SHAFT NO 3 BEARING SCAVENGE VENT RELIEF VALVE OIL TEMP BULB LUBE AND SCAVENGE PUMP RELIEF VALVE BYPASS VALVE OIL FILTER BYPASS VALVE OIL COOLER DRIVE END ACCESSORY GEARBOX OIL VENT LOW OIL PRESSURE LIGHT OIL PRESSURE SWITCH OIL PRESSURE GAGE LO OIL PRESS ENGINE NACELLE BULKHEAD OIL PRESSURE TRANSMITTER GEARBOX SCAVENGE FRONT FRAME SUMP SCAVENGER 6 5 4 3 2 1 ...

Page 148: ...e to position the variable inlet guide vanes and the engine compressor bleed valves The function of the variable geometry system is to prevent compressor stalls and surging when operating in a low power range and dur ing acceleration and deceleration The system includes bleed valves at the third fourth and fifth stages of the compressor When these valves are moved toward open a volume of compresso...

Page 149: ...fuel manifold and two outlet ports which supply fuel to the noz zle section through two tubes the primary and secondary fuel nozzles tubes The air cooled nozzles section contains a primary and second ary orifice The initial flow of fuel into the fuel nozzle passes through the divider housing and the primary fuel tube to the primary nozzle ori fice where the spray pattern is formed for combustion A...

Page 150: ...engine bleed air system The primary air system see Figure 7 1 is that portion of the engine air system which is associated partly with combustion and partly with the direct cooling It is described as follows The combustion air system is that portion of the primary air system which is directly asso ciated with combustion and thrust The vari able inlet guide vanes in the front frame annulus guide th...

Page 151: ...OW DIVIDER FUEL NOZZLES 12 RH MANIFOLD OIL IN TO EPA COLLECTOR OIL OUT SENSE LINE FUEL FILTER BYPASS FROM TANK FILTER FUEL SHUTOFF VALVE MOTIVE FLOW SHUTOFF VALVE LH MANIFOLD BOOST ELEM GEAR ELEM MAIN FUEL CONTROL OVERSPEED GOVERNOR FLOW METER FILTER PRESSURIZING AND DRAIN VALVE OIL COOLER DRAIN FUEL ELECTRICAL HP FUEL PRESSURE REGULATED PRESSURE SUPPLY FUEL LEGEND ...

Page 152: ...overboard as scheduled by the fuel controller to maintain air flow stability within the compressor and to prevent compressor stalls Some of the compressor discharge air is bled off through two main frame ports for pressur ization and heating of the airplane cabin windshield defog wing heat pressurization jet pump and on 24 297 and subsequent and 25 135 181 and subsequent for hydraulic reservoir pr...

Page 153: ...each engine on 23 models and 24 models through 24 180 and 25 003 through 024 and a probe in the ram air duct On all other models the inlet air pressure is supplied from the copilot s pitot tube and there is only one transducer per engine The inlet and exhaust pressure sig nals are sent to the appropriate EPR trans ducer where they are converted to electrical signals amplified and sent to the EPR g...

Page 154: ...uses 26 VAC NOTE There is one light for both engines therefore if only one engine is op erating the red low oil pressure light will be illuminated OIL TEMPERATURE Two oil temperature indicators powered by 28 VDC are installed in the instrument cluster on the switch panel and a probe is installed in the bot tom of each oil tank ENGINE STARTING Moving the starter generator switch to the START positi...

Page 155: ...nal to the difference in fre quency of the tach generators Clockwise rota tion is for the right tach fast and counterclock wise is for the left tach fast Synchronization is accomplished by adjusting either engine thrust lever until the wheel stops rotation THRUST REVERSERS OPTIONAL GENERAL The thrust reversers Figure 7 15 are an ad ditional deceleration system which may be used anytime the airplan...

Page 156: ...mits en gine rpm in reverse to a maximum of 85 A system of mechanical and electrical inter locks is provided to prevent unwanted or in advertent deployment With the engine thrust levers in forward thrust above idle the T R system cannot be armed Electrical inter locks are provided through landing gear squat switches to prevent in flight deployment AUTOMATIC STOW An automatic stow system is also in...

Page 157: ...ch engages with another bevel gear mounted in the power takeoff housing per pendicular to the engine centerline A radial shaft which is splined to the driver shaftgear transmits the power radially out of the engine through the six o clock mainframe strut The out board end of this radial drive shaft is splined to the transfer gearbox in the CJ610 1 and di rectly to the accessory gearbox in the CJ61...

Page 158: ... 115 volt AC bus C Resistance bulbs at the oil pump outlet D The 26 VAC system 4 The primary thrust indicator for the CJ610 engine is A EGT B Fuel flow C Engine pressure ratio EPR D Rpm 5 During start ignition occurs when the A Rpm indicates 10 B Thrust lever is moved from the CUT OFF position C Start GEN switch is moved to the START position D Generator magnetic pickups sense 8 rpm 6 If fuel flow...

Page 159: ...1 Sensing Elements and Control Units 8 1 Fire Lights 8 2 Fire Detection System Test 8 2 Exterior Extinguisher Discharge Indicators 8 3 ENGINE FIRE EXTINGUISHING 8 3 Extinguisher Containers 8 3 Operation 8 3 QUESTIONS 8 6 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 160: ...re Extinguisher Discharge Indicators 8 3 8 4 Engine Fire Extinguishing System Airplanes with Glareshield Warning Lights 8 4 8 5 Engine Fire Extinguishing System Airplanes without Glareshield Warning Lights 8 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 161: ...tion system is incorporated GENERAL Fire detection consists of separate and inde pendent systems for the left and right engines separate indicating fire warning systems and a fire detection test system A two bottle fire extinguishing system is com mon to both engines The system is such that either of two bottles of extinguishing agent can be discharged to either engine or both bottles can be disch...

Page 162: ...hrough 24 129 On these airplanes they are located in the nose compartment DC electrical power for the system is supplied through circuit breakers on the appropriate pilot s and or copilot s circuit breaker panels FIRE LIGHTS The red FIRE warning lights are located at each end of the glareshield Figure 8 1 or on the readout panel of airplanes without glareshield warning lights In the event of an en...

Page 163: ...bed to each engine cowling to provide the airplane with a two shot system The containers will fully discharge in one to two seconds A pressure gage mounted on each container indicates the charge of the container A thermal relief valve on each con tainer is plumbed to a thermal red discharge indicator to relieve bottle pressure when bot tle temperature reaches 217ºF Access to the fire extinguishing...

Page 164: ...lves Figure 8 5 and arms the No 1 and No 2 dis charge switches Depressing the No 1 discharge switch fires a bottle to the selected engine If a second charge of extinguishing agent is desired de pressing the No 2 discharge switch fires the remaining bottle to the same engine Returning the guarded FIREWALL SHUT OFF switch to the off position opens the hy draulic and fuel shutoff valves and disarms t...

Page 165: ...LLE LH NACELLE FUEL SHUTOFF VALVE HYDRAULIC SHUTOFF VALVE ENGINE EXTINGUISHING MANUAL DISCHARGE THERMAL DISCHARGE LEGEND LH RH F I R E W A L L S H U T O F F F I R E W A L L S H U T O F F NO 1 NO 2 DISCHARGE SWITCHES LH CONTAINER RELIEF VALVE RELIEF VALVE PRESSURE GAGE PRESSURE GAGE RH CONTAINER TWO WAY CHECK VALVES Figure 8 5 Engine Fire Extinguishing System Airplanes without Glareshield Warning L...

Page 166: ...s possible both bottles discharge simultaneously when either ARMED button is pressed 5 Airplanes with glareshield warning lights When the left FIRE light is depressed A It discharges one extinguisher into the left nacelle B It closes the main fuel and hydraulic shutoff valves for the left engine and arms the left ARMED lights C It discharges one extinguisher and arms the second D It ruptures the y...

Page 167: ...NERAL 9 1 DESCRIPTION AND OPERATION 9 2 SNs 23 003 through 24 349 and 25 003 through 25 226 9 2 SNs 24 350 and Subsequent and 25 227 and Subsequent 9 2 QUESTIONS 9 6 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 168: ...tem SNs 23 003 through 24 349 and 25 003 through 25 226 9 3 9 2 Pneumatic System SNs 24 350 and Subsequent and 25 227 and Subsequent 9 4 9 3 AIR BLEED Switches 9 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 169: ...ures are given by illumination of warning lights on the glareshield annunciator panel see Annunciator Panel section VALVE L R CO BLEED AIR 5 15 20 AIR CHAPTER 9 PNEUMATICS 9 1 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international INTRODUCTION The Lear 20 series pneumatic system uses bleed air extracted from the engine compressor section Bleed air is used for...

Page 170: ...mum airflow rate On SNs 24 230 through 24 349 25 061 and 25 070 through 25 226 it is controlled by a three position AIR BLEED switch labeled OFF NORM and MAX on the pressurization module The OFF position closes the valve completely MAX position opens the valve to full flow NORM position allows sense line pressure from the venturi located downstream to modulate the flow control valve to maintain a ...

Page 171: ...E BLEED AIR RH ENGINE ON OFF AIR BLEED HYDRAULIC RESERVOIR PRESSURE BLEED AIR SHUTOFF VALVES ARE INSTALLED ON 23 003 THROUGH 23 029 UNLESS MODIFIED BY SK140 SN 24 297 THROUGH 349 AND 25 135 AND 181 THROUGH 226 IF INSTALLED PRESSURIZATION JET PUMP WINDSHIELD HEAT ANTI ICE BLEED AIR SHUTOFF VALVE ON LH ENGINE OFF AIR BLEED REGULATED BLEED AIR BLEED AIR LEGEND Figure 9 1 Pneumatic System SNs 23 003 t...

Page 172: ...G PRESS VALVE LH AIR BLEED EMER ON OFF OVERTEMPERATURE SWITCH LH ECS VALVE TO CABIN WINDSHIELD HEAT WING HEAT OFF ON EMER OVERTEMPERATURE SWITCH SERVO PRESS RH ECS VALVE TO CABIN L CAB AIR R CAB AIR CONDITIONED AIR RAM AIR REGULATED SERVO AIR BLEED AIR LEGEND H VALVE REGULATOR RAM AIR OUT HEAT EXCHANGER TEMP CONTROL ALCOHOL ANTI ICE FLOW CONTROL VALVE CABIN RAM AIR IN EMERG PRESS VALVE BLEED AIR M...

Page 173: ... is controlled by a two position CAB AIR switch on the pressurization module The OFF position closes the valve completely The ON position allows sense line pressure from the venturi located downstream to modulate the flow control valve to maintain a constant airflow to the cabin With loss of DC electrical power the valve fails to the normal ON position Cabin Air Warning Lights The red L and R CAB ...

Page 174: ... on C Remains in the last position D Moves to the fully open position 3 In the event of single engine operation the check valves in the bleed air line from each engine A Must be electrically closed B Allow negative airflow C Prevent airflow into the inoperative engine D Shut off the pneumatic system 4 For normal cabin pressurization to occur after takeoff the pneumatic system bleed air AIR BLEED C...

Page 175: ...L 10 1 ICE DETECTION 10 3 Windshield Ice Detection 10 3 Wing Ice Detection 10 3 ANTI ICE SYSTEMS 10 3 Engine Anti ice System Nacelle Heat 10 3 Windshield Anti ice Defog and Rain Removal System 10 5 Windshield RADOME Alcohol Anti ice System 10 8 Wing and Horizontal Stabilizer Anti ice System 10 13 Pitot Static and Angle of Attack Vane Anti ice System 10 14 QUESTIONS 10 15 ...

Page 176: ...m 10 6 10 7 IN NORMAL OUT DE FOG Knob 10 5 10 8 WSHLD HEAT Switches 10 7 10 9 Windshield Heat Diagram 10 8 10 10 Alcohol Reservoir 10 9 10 11 WSHLD RADOME Switch 10 9 10 12 Alcohol System SNs 24 181 through 24 349 and 25 025 through 25 226 and Airplanes Modified for Known Icing Conditions 10 10 10 13 Alcohol System SNs 24 350 and Subsequent and 25 227 and Subsequent 10 11 10 14 Wing and Horizontal...

Page 177: ...tions on SNs 24 181 and sub sequent 25 025 and subsequent and earlier SNs modified for flight into icing conditions Airplane anti icing is accomplished through the use of electrically heated anti ice systems engine bleed air anti ice systems and an al cohol anti ice system Electrically heated components include pitot tubes static ports shoulder static ports stall warning vanes nacelle inlet and ho...

Page 178: ...Takeoff into icing conditions is permitted with all bleed air anti icing systems on The RAT gage should be checked frequently when flying in or en tering areas of visible moisture During descents the cabin altitude may in crease unless sufficient engine rpm is main tained to compensate for the additional bleed air use To ensure adequate bleed air for anti ice protection and cabin pressuriza tion m...

Page 179: ...on The ice detection lights are illuminated whenever airplane electrical power is on The lights use DC power routed through the L and R ICE DET circuit breakers located on the pilot s copilot s or baggage compartment circuit breaker panels WING ICE DETECTION During darkness the recognition light Figure 10 3 can be used to confirm ice buildup on the right tip tank Some airplanes are equipped with a...

Page 180: ...OSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 10 4 Engine Anti ice System R ENG ICE NACELLE HEAT SW 28 VDC ON OFF NAC HEAT EITHER GENERATOR WARN LIGHT 28 VDC INLET HTR SQUAT SW RELAY BOX ...

Page 181: ...ired to extin guish the lights Inlet Heater Light A temperature sensing switch is located in the nacelle on each engine to detect a possible overheat condition A single amber INLET HTR light see Annunciator Panel section on the glareshield illuminates when either nacelle reaches 190 3ºF and extinguishes at 180ºF This light is connected through the squat switch relay box subsequent to SNs 24 209 an...

Page 182: ...ESSURE BULKHEAD AFT PRESSURE BULKHEAD WINDSHIELD IN NORMAL OUT DE FOG OVERBOARD DRAIN CHECK VALVE CHECK VALVE DEFOG PRESSURE REGULATOR VALVE WSHLD HEAT RH ENGINE LH ENGINE BLEED AIR TO WING L E HEAT DUCT DEFOG SHUTOFF VALVE ON OFF AUTO MAN FOOTWARMERS WINDSHIELD HEAT BLEED AIR TO CABIN FLOW CONTROL VALVE BLEED AIR MANIFOLD Figure 10 6 Windshield Anti ice Defog Rain Removal System ...

Page 183: ...it can be closed only by holding the ON OFF switch to OFF with MAN se lected for at least four seconds The pressure regulator valve is solenoid op erated and is deenergized closed It is energized open when airplane power is on Its function is to regulate the engine bleed air from the man ifold to 16 psi Automatic Operation The flow of bleed air to the windshields is con trolled in the automatic mo...

Page 184: ...re disabled Overheat protection is provided by the high limit switches which close the pressure regulator valve if activated WINDSHIELD RADOME ALCOHOL ANTI ICE SYSTEM General Methyl alcohol from a reservoir Figure 10 10 located in the left side of the nose com partment is provided to prevent ice formation 10 8 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety internat...

Page 185: ...mber ALC AI light when the reservoir is empty or if the pump fails The light extinguishes when the control switch is turned off SNs 24 350 and Subsequent and 25 227 and Subsequent Methyl alcohol is stored in a 1 75 gallon reser voir When the cockpit control switch is po sitioned to WSHLD RADOME or to RADOME circuits are completed to position a three way valve in the fluid supply line Figure 10 13 ...

Page 186: ...e and duration of the supply is re duced to approximately 45 minutes NOTE This system is still operational if both emergency pressurization valves are in emergency provided DC power is available 10 10 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international OFF RADOME WINDSHIELD RADOME ORIFICE ASSEMBLY ANTI ICE VALVE N C LOW PRESSURE SWITCH PRESSURE RELIEF OVER...

Page 187: ... CHECK VALVE PILOT S WINDSHIELD OUTLET THREE WAY SHUTOFF VALVE FILTER SHUTOFF VALVE AND PRESSURE REGULATOR OVERBOARD DRAIN OVERBOARD DRAIN BLEED AIR FROM LH ENGINE PRESSURE RELIEF VALVE ALC AI RADOME OUTLET ELECTRICAL BLEED AIR UNREGULATED REGULATED PRESSURE LEGEND ALCOHOL PRESSURE Figure 10 13 Alcohol System SNs 24 350 and Subsequent and 25 227 and Subsequent ...

Page 188: ...l WING TEMP WING TEMP 25 260 AND SUBSEQUENT WING OV HT SCUPPER SCUPPER STAB AND WING HEAT CONTROL VALVE LH ENGINE RH ENGINE TO DEFOG SYSTEM TO AIR CONDITIONING PRESSURIZATION SYSTEM STAB HEAT ANTI ICE BLANKET ON OFF RELAY BOX SEQUENCE TIMER Figure 10 14 Wing and Horizontal Stabilizer Anti ice System ...

Page 189: ...ust not be oper ated when the light is illuminated The ther mocouple that operates the light is located at the right wing fuselage root on the structure A wing temperature indicator Figure 10 15 located on the pilot s subpanel has three col ored ranges on a round dial From left to right these arcs are red green and yellow Red arc Wing temperature is below 35ºF Green arc Wing temperature is above 3...

Page 190: ...ot tubes and both stall vanes are heated A condensate drain valve is installed for each system One is located adjacent to each nose wheel well door Some airplanes may have a light to indicate that a system has failed or that the PITOT HEAT switch is not turned on The static port heaters are wired through the re spective PITOT HEAT circuit breakers but not through the PITOT HEAT switches Therefore ...

Page 191: ...ing equipment should be turned on A When in icing conditions B Before entering icing conditions C Before takeoff D During climbout 5 With the loss of airplane electrical power anti icing is lost for A All systems B Pitot tubes static ports and AOA vanes only C All systems except the nacelle inlet lips D All systems except the engine front frame 6 When the NAC HEAT switches are turned on the most p...

Page 192: ...ECTION CONTENTS Page INTRODUCTION 10A 1 GENERAL 10A 1 ICE DETECTION 10A 2 ANTI ICE SYSTEMS 10A 3 Engine Anti ice System Nacelle Heat 10A 3 Windshield Anti ice Defog and Rain Removal System 10A 5 Windshield Alcohol System 10A 9 Wing Anti ice System 10A 9 Pitot Static and Angle of Attack Vane Anti ice System 10A 11 QUESTIONS 10A 12 ...

Page 193: ...Ice Detection System 10A 2 10A 3 Ice Detection Lights 10A 3 10A 4 Engine Anti ice System 10A 4 10A 5 Defog Push Pull Knobs 10A 5 10A 6 Defog System Model 23 10A 6 10A 7 Defog System SNs 24 100 through 180 and 25 003 through 024 10A 7 10A 8 Defog Knob 10A 8 10A 9 Windshield Alcohol System 10A 9 10A 10 Wing Anti icing System 10A 10 10A 11 Pitot Static and AOA Anti ice System 10A 11 ...

Page 194: ... is used for deicing Rain removal is ac complished with bleed air by a service kit Engine bleed air is used to heat the windshields the wing leading edge and the engine front frame The engine front frame includes the guide vanes variable guide vanes and the nose cone Icing conditions exist if visible moisture is present and the ram air temperature RAT is 10ºC or lower During daylight operation ice...

Page 195: ...des mechanical power that allows a three phase cycling operation The phases are neutral sensing and deicing When the detector probe is subjected to ram air of 40 knots or more a pressure differential is 10A 2 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international FRONT FRAME ANTI ICING BLEED AIR NACELLE CAP ANTI ICE ELECTRIC BLANKET WING LEADING EDGE ANTI ICE...

Page 196: ...he windshield ice de tection lights if installed cause red areas approximately 1 1 2 inches in diameter to appear on the windshield if particles of ice or moisture form The light on the pilot s side is located in the defog airflow stream and the light on the copi lot s side is outside the defog airflow stream If the windshield defog system is operating the copilot must monitor the light on his sid...

Page 197: ...on on the warning panel Therefore the ENG ICE light only indicates insufficient bleed air pressure to the front frame Adequate pressure to the front frame requires approximately 70 rpm on the ground and at least 80 rpm while airborne Electrical power for heating the nacelle lip is provided by its respective generator Loss of a generator results in the loss of the associated nacelle heat Each nacel...

Page 198: ...h in the defog duct illuminates the red W S O HEAT light on the warning panel when tem perature reaches 205ºF the light extinguishes at 180ºF The defog system should be turned off or airflow decreased when this light illu minates in order to protect the windshield from possible distortion The water accumulator installed in the ex ternal defog ducting forward of frame 5 pre vents any accumulated wa...

Page 199: ...S PLENUM CHAMBER PLENUM CHAMBER CHECK VALVE INTERNAL DEFOG COPILOT S EXTERNAL DEFOG WATER ACCUMULATOR WATER ACCUMULATOR PULL PULL PULL TO FOOTWARMER DEFOG OFF PILOT S EXTERNAL DEFOG DEFOG RELAY SHUTOFF VALVE 220 180 F W S O HEAT SHUTOFF VALVE SHUTOFF VALVE CHECK VALVE TO AIR CONDITIONING SYSTEM SNs 23 003 THROUGH 23 008 RH ENGINE LH ENGINE Figure 10A 6 Defog System Model 23 ...

Page 200: ... VALVE TO CABIN FLOW CONTROL VALVE EMER CAB PRESS EXT DEFOG ON DEFOG OFF CHECK VALVE CONDITIONED AIR FROM CABIN DISTRIBUTION SYSTEM FOOTWARMERS IN NORMAL OUT DEFOG W S O HEAT IN PILOT AND COPILOT OUT PILOT PILOT S EXTERNAL OUTLET WINDSHIELD INTERNAL OUTLET COPILOT S EXTERNAL OUTLET CHECK VALVE BLEED AIR 210 F Figure 10A 7 Defog System SNs 24 100 through 180 and 25 003 through 024 ...

Page 201: ...s the red W S O HEAT light to il luminate when the temperature reaches 210ºF The light extinguishes when the temperature drops to 180ºF When the W S O HEAT light illuminates the defog system should be turned off or the airflow decreased to prevent possi ble distortion to the windshield To turn off the defog system toggle the DEFOG switch to OFF until airflow has stopped then push the top knob in I...

Page 202: ...to 10 gph through the two external defog nozzles WING ANTI ICE SYSTEM Eighth stage engine bleed air is provided to prevent the formation of ice on the wing lead ing edges and is certified for use per FAR 25 for flights below 22 000 feet Bleed air is passed through a tube with small holes that allows the heated air to be discharged against 10A 9 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TR...

Page 203: ...The later kind is a Whittaker valve which is electrically energized open and fails to the closed position Either valve reg ulates pressure to the wing ducts at 8 to 20 psi A green WING HEAT light illuminates when the duct temperature reaches 215ºF A red WING OVERHEAT light illuminates when the leading edge structure temperature reaches 215ºF Do not operate the system with the red light illuminated...

Page 204: ...en completed If SK 23 24 226 has been completed the two forward ports on each side of the nose are heated anytime the battery switch is turned on The third and rearmost static port on the right side is not heated It does however have an alternate source inside the nose compartment NOTE On airplanes with a Century III wing the shoulder static ports are heated NOTE SNs 23 003 through 069 not modi fi...

Page 205: ...witchtoOFF C Reduce power D Turn the BLEED AIR switch to OFF until the light extinguishes 4 Anti icing equipment should be turned on A During descent B Before entering icing conditions C Before takeoff D During climbout 5 With the loss of airplane electrical power anti icing is lost on A All systems B Pitot static and AOA vanes only C All systems except the nacelle inlet lips D All systems except ...

Page 206: ...ng System SNs 24 230 through 349 and SNs 25 003 through 226 11 6 Air Conditioning System SNs 23 003 through 24 229 11 10 AUXILIARY AIR CONDITIONING SYSTEMS 11 13 General 11 13 Distribution System 11 13 Auxiliary Cooling System 11 14 Auxiliary Heating System Optional Not available on SNs 23 003 through 24 129 11 16 QUESTIONS 11 19 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL F...

Page 207: ... SNs 23 003 through 24 229 11 11 11 11 AIR BLEED and NORM MAX Switches 11 12 11 12 Evaporator and Blower Assembly SNs 23 003 through 24 129 11 13 11 13 Evaporator and Blower Assembly SNs 24 130 through 203 and 25 003 through 039 11 13 11 14 Evaporator and Blower Assembly SNs 24 204 and Subsequent and 25 040 and Subsequent 11 13 11 15 Diverter Door Control 11 14 11 16 Fan Rheostat 11 14 11 17 COOL ...

Page 208: ... heating and cooling are accomplished by controlling the temperature of the bleed air entering the cabin The distribution systems vary slightly based on model and serial number Supplemental cooling is provided by a Freon refrigeration system that may be used on the ground and in the air up to a maximum altitude of 18 000 feet The auxiliary heating system if installed may be used on the ground and ...

Page 209: ...7 AND SUBSEQUENT Figure 11 2 illustrates the air conditioning system LH and RH Bleed Air Shutoff Valves Two bleed air shutoff valves are installed in each duct to the bleed air manifold in the tail cone and are controlled by the respective LH and RH AIR BLEED switches on the control panel In the OFF position all bleed air is shut off from the respective engine to the bleed air manifold In the ON p...

Page 210: ...OWER MOTOR CABIN AIR DIFFUSERS TYPICAL CHECK VALVE BLEED AIR DUCT TEMP LIMITER DUCT TEMP SENSOR RAM AIR IN LH BLEED AIR VALVE SERVO BLEED AIR RAM AIR CHECK VALVE VENTURI HOT AIR BYPASS H VALVE BLEED AIR MANIFOLD EMERGENCY PRESSURIZATION VALVE FLOW CONTROL VALVE RAM AIR OUT CHECK VALVE H VALVE IND RH BLEED AIR VALVE COLD HOT ON OFF CAB AIR COOL COLD HOT AUTO MAN FAN OFF C A B I N T E M P H VALVE H ...

Page 211: ...e to the heat exchanger for cool ing and some to bypass the heat exchanger The result is a mixture of the two airflows thereby conditioning the bleed air before it enters the cabin area The position of the H valve is indicated on the H VALVE indicator located on the copilot s instrument panel Figure 11 4 Figure 11 4 H VALVE Indicator Current Models The H valve butterfly is positioned pneumat icall...

Page 212: ...stribution check valve is located at the aft end of each cabin duct These valves are functionally related to the pres surization system as described in Chapter 12 of this manual On SNs 24 350 and subsequent and 25 227 and subsequent distribution of air changes when either or both emergency pressurization valves are positioned to emergency If only one emergency valve is positioned to emergency all ...

Page 213: ...fly The H VALVE indicator see Figure 11 4 displays the relative position of the H valve which is the only component in the system that requires DC electrical power DC power is provided through the H VAL IND circuit breaker on the left main bus With the AUTO MAN knob selector valve in the AUTO position the servo pressure control network samples the needle valve setting COLD HOT knob position the ca...

Page 214: ... M P C ABIN X 1000 FT A L T ITUDE X 1 0 0 0 SKIN TEMP SENSOR CABIN TEMP SENSOR CHECK VALVE TO WING L E ANTI ICE SYSTEM LH ENGINE RH ENGINE BYPASS VALVE RAM AIR OUT HEAT EXCHANGER FLOW CONTROL VALVE BLEED AIR CHECK VALVE HIGH LIMIT THERMOSTAT DUCT TEMP SENSOR RAM AIR CHECK VALVE RAM AIR IN CHECK VALVE TEMPERATURE CONTROL UNIT FOOTWARMERS AND EXTERNAL DEFOG BLEED AIR FOOTWARMERS AND EXTERNAL DEFOG B...

Page 215: ...he cabin temperature control indicator H VALVE indicator on the copilot s subpanel indicates the position of he H valve and is operated by 28 VDC Ram Air Heat Exchanger The heat exchanger is located inside he tail cone It consists of a bleed air core surrounded by a ram air plenum Cool air enters the room air inlet in the dorsal fin and flows through the plenum across the bleed air core thus cool ...

Page 216: ...in air distribution ducts bypassing the heat exchanger depending on the position of the H valve Rapid cabin tem perature fluctuations are prevented by a duct temperature sensor in the supply duct and a high temperature limit switch prevents the duct temperature from exceeding safe limits There are usually two 28 VDC circuit break ers one for automatic and one for manual cabin temperature control A...

Page 217: ...unctions in both au tomatic and manual temperature control modes and limits the maximum temperature of the cabin bleed air duct Excessive duct temper atures provide a signal voltage that causes the H valve to drive toward the cold position Cabin Temperature Sensor A cabin temperature sensor located behind the copilot s seat monitors cabin temperature and provides signals to reposition the H valve ...

Page 218: ... CABIN OUTLETS CONDITIONED AIR INTERNAL DEFOG CONDITIONED AIR CABIN TEMP SENSOR CABIN OUTLETS CONDITIONED AIR CABIN CHECK VALVE RAM AIR CHECK VALVE CABIN CHECK VALVE HIGH LIMIT THERMOSTAT HEAT EXCHANGER AND DAMPER FLOW CONTROL SOLENOID FLOW CONTROL VALVE RAM OUT VENTURI CHECK VALVE DEFOG SHUTOFF VALVE DORSAL RAM INLET CHECK VALVE RH ENGINE SNs 23 003 THROUGH 23 029 EXCEPT AIRPLANES MODIFIED BY SK2...

Page 219: ...s and overboard just aft of the tailcone access door This results in a sub stantial reduction of bleed air temperature Ram Air Ventilation In the event that the aircraft is unpressurized in flight air for circulation and ventilation of the cabin and cockpit areas is provided by ram air ducted into the conditioned bleed air distribution system During the normal operation a one way check valve in th...

Page 220: ... and cockpit fan may be used simply to recirculate air within the cabin and cockpit areas or by using the auxiliary cooler or heater to cool or to heat the recirculated air A ground power unit or an engine driven generator must be used to operate either the cooling or heating systems on the ground DISTRIBUTION SYSTEM The heart of the distribution system is the evap orator and blower assembly insta...

Page 221: ...is rotated to its extreme in the CLOSE direction the doors are flushed with the bottom of the ducting maximizing airflow into the cabin Cockpit Fan Distribution Between the two ducts fed by the cabin blowers is another duct which encloses the axial cock pit fan The cockpit fan is a 28 VDC fan con trolled by a rheostat located on the copilot s sidewall Figure 11 16 This fan draws air from the bagga...

Page 222: ...ndenser is a plate and fin unit High pressure high temperature vapor enters the condenser from the compressor This vapor is then cooled by the air passing over the condenser surface and changes to liquid Heat from the condenser is removed by a fan mounted on the compressor motor shaft The receiver dehydrator removes the small traces of moisture that may remain in the system A sight glass for obser...

Page 223: ...imum effectiveness on the ground the AIR BLEED or CAB AIR switch should be turned off when the engines are running Manually operated diverter doors installed in the air ducts from the evaporator may be positioned to direct some of the cool air into the baggage compartment When the control switch is placed in the FAN position 28 VDC is applied to the cabin fan which circulates only the cabin air Th...

Page 224: ...re Should either thermal switch fail to shut off power to the affected element at the high limit the thermal fuse melts through and discon nects the affected element precluding element overheat Circulation of air is described in Cabin Blower Distribution When the auxiliary heater is in operation the heater elements are disconnected by the safety switch if for any reason the diverter doors are open...

Page 225: ...AL FUSE HEATER COILS DIVERTER DOOR CONTROL CABLE CABIN BLOWER DUCT HEATER ELEMENTS THERMOSWITCH HIGH LIMIT 150 F LOW LIMIT 125 F HEATER SAFETY SWITCH DIVERTER DOOR BELLCRANK SWITCH ROLLER DIVERTER DOOR THERMOSWITCH AIRPLANES WITH SINGLE EVAPORATOR DUCT SNs 25 003 THROUGH 25 039 AND SNs 24 130 THROUGH 24 203 EVAPORATOR AND BLOWER ASSEMBLY AUXILIARY CABIN HEATER SAFETY SWITCH AIRPLANES WITH DUAL EVA...

Page 226: ...n using the auxiliary heater the heated air blows out through the A Conditioned air outlets B Louvered grille above the divan seat C Overhead cockpit air outlets D Overhead passenger outlets 6 The Freon system should not be used above A 5 000 feet B 8 000 feet C 10 000 feet D 18 000 feet 15 000 feet model 23 7 The Freon system automatically disengages A During engine start B Upon touchdown C When ...

Page 227: ... 12 1 GENERAL 12 1 SYSTEM DESCRIPTION 12 3 Components 12 3 Indicators 12 8 Normal Operation 12 9 Flight Operation 12 9 EMERGENCY PRESSURIZATION 12 10 QUESTIONS 12 13 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 228: ...2 4 UP DN Lever 12 5 12 5 HORN SILENCE Switch 12 6 12 6 AIR BLEED Switches 12 8 12 7 Pressurization Indicators 12 8 12 8 IN NORMAL OUT DE FOG Knob 12 10 TABLES Table Title Page 12 1 Automatic Protection and Warning Features SNs 24 230 through 349 and 25 067 through 226 12 11 12 2 Automatic Protection and Warning Features SNs 24 350 and Subsequent and 25 227 and Subsequent 12 12 FOR TRAINING PURPOS...

Page 229: ... operated to maintain the proper dif ferential between cabin and ambient pressures Inward and outward relief for both negative and excess positive differential conditions are in corporated to protect the aircraft structure The pressurization control system is completely pneumatic during normal in flight automatic operation Pneumatic pressure is provided by a vacuum jet pump Control pressure vacuum...

Page 230: ...VE N O ENERGIZED CLOSED ON GND SOL VALVE NC ENERGIZED OPEN ON GND WITH CAB AIR OFF PRESS DIFF RELIEF 9 7 PSID CAB ALT LIM 11 500 FT 1 500 FT SOL VALVE N O ENERGIZED CLOSED IN MANUAL ABOVE 8 750 250 FT OR ON GND CABIN ALT LIGHT DN OUTFLOW VALVE STATIC PRESS NOSE CABIN STATIC FILTER CABIN TAILCONE SOL VALVE NC ENERGIZED OPEN ON GND CONTROL PRESSURE VACUUM SOURCE FILTER CAB ALT LIMITER 11 500 FT 1 50...

Page 231: ...ative pressure while a regulator ensures that the negative pressure maintains a constant differential pressure with respect to cabin pressure This negative pressure vac uum is furnished to the pressurization con trol module which uses it to control the outflow valve Pressurization Control Module The pressurization control module is located on the copilot s lower instrument panel The controls on th...

Page 232: ...LVE N O ENERGIZED CLOSED IN MANUAL ABOVE 10 000 FT OR ON GND DN OUTFLOW VALVE STATIC PRESS NOSE CABIN STATIC FILTER CABIN TAILCONE SOL VALVE NC ENERGIZED OPEN ON GND FILTER CAB ALT LIMITER 11 000 FT 1 000 FT CABIN PRESS ENG BLEED AIR FILTER REG JET PUMP SAFETY VALVE ORIFICE STATIC PORT ENGINE BLEED AIR VACUUM CONTROL PRESSURE LEGEND STATIC PRESSURE CABIN PRESSURE MODIFIED CONTROL PRESSURE C A B I ...

Page 233: ...atic mode the CABIN CONTROLLER also attempts to control the outflow valve and as soon as the lever is released the CABIN CONTROLLER returns cabin pressure to the original value Differential Pressure Relief Valve Primary The primary differential pressure relief valve functions in association with the CABIN CON TROLLER Its purpose is to prevent exceed ing normal differential limits On SNs 24 230 thr...

Page 234: ... to 8 000 feet or below the aneroid resets and deenergizes the solenoid valve open provided the AUTO MAN switch is in AUTO On SNs 24 350 and subsequent and 25 227 and subsequent the operation is the same as early SNs except that the aneroid switch ac tuates at 8 750 250 feet and resets at 7 200 feet Also when actuated it causes the amber CAB ALT annunciator see Annunciator Panel section to illumin...

Page 235: ...ntial pressure to 9 2 psi on SNs 24 230 through 349 and 25 067 through 226 On subsequent SNs the pressure is limited to 9 7 psi Cabin Altitude Limiter Secondary The cabin altitude limiter for the cabin safety valve serves the same purpose as the cabin al titude limiter for the outflow valve If the sec ondary differential pressure relief valve malfunctions causing the safety valve to open the cabin...

Page 236: ...t has an amber band from 8 9 to 9 2 psi on early aircraft and 9 4 to 9 7 psi on cur rent aircraft A red band appears above 9 2 psi on early aircraft and above 9 7 on current air craft Cabin altitude should always be equal to or less than the aircraft altitude Cabin Vertical Speed Indicator The cabin vertical speed indicator is positioned to the right of the cabin altimeter It provides an indicatio...

Page 237: ... selected Adjust the CABIN CONTROLLER as necessary when changing cruise altitude Monitor cabin altitude and differential pres sure throughout the flight Manual If the CABIN CONTROLLER is not function ing properly follow the Manual Mode Operation procedures in Section 2 of the approved AFM Manual mode operation is established when the AUTO MAN switch is placed to MAN This closes the manual mode sol...

Page 238: ...osition and require both servo bleed air pres sure and DC power to position them to normal Cockpit control of the valves is provided by the three position OFF ON EMER AIR BLEED switches on some airplanes the switches are labeled BLEED AIR Automatic functioning occurs as a result of ex cessive cabin altitudes or DC power failure With the AIR BLEED switches in ON a solenoid on each emergency valve i...

Page 239: ...lve If the emergency valves are positioned to emer gency for any reason they may be reset by cy cling the AIR BLEED switches to OFF then back to ON if power is available and the cabin altitude is at or below 7 200 feet During the first engine start the valves auto matically shift from emergency to normal as servo air pressure from the engine becomes available A slight rush of air into the cabin is...

Page 240: ...mergency pressurization valves are activated by aneroid switches directing engine bleed air directly into the cabin Cabin altitude limiters actuate 10 100 250 feet Cabin altitude warning horn sounds initiate emergency descent Passenger oxygen masks are deployed See Chapter 17 Cabin overhead lights illuminate 24 255 and subsequent 25 090 094 and subsequent and earlier airplanes modified by AAK 73 6...

Page 241: ...ctuate to provide cabin pressure D Both B and C 4 The cabin altitude warning horn sounds when the cabin altitude reaches A 8 750 250 feet B 9 500 250 feet C 10 100 250 feet D 11 500 1 500 feet 5 To dump residual cabin pressure on touchdown A The outflow valve opens automati cally B The cabin safety valve opens auto matically C The flow control valve closes auto matically D The bleed air shutoff va...

Page 242: ...TRODUCTION 12A 1 GENERAL 12A 1 SYSTEM DESCRIPTION 12A 1 Components 12A 1 Indicators 12A 10 Operation 12A 11 EMERGENCY PRESSURIZATION 12A 12 QUESTIONS 12A 13 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 243: ...Ns 24B 185 188 and 190 through 209 and 25 027 and 029 through 045 12A 5 12A 5 Pressurization System SNs 24B 210 through 229 and 25 046 through 063 except 25 061 12A 6 12A 6 Pressurization Control Module 12A 7 12A 7 Outflow Valve Typical 12A 8 12A 8 Cabin Safety Dump Switch 12A 9 12A 9 Cabin Safety Valve Typical 12A 9 12A 10 Cabin Altitude and Differential Pressure Indicator 12A 10 12A 11 Cabin Ver...

Page 244: ... the nor mal air distribution ducts The level of cabin pressure is controlled by regulating the dis charge of air overboard through the outflow valve Control may be either manual or auto matic For automatic pressurization control 115 VAC is required SYSTEM DESCRIPTION COMPONENTS The pressurization system Figures 12A 1 through 12A 5 consists of an outflow valve on the forward pressure bulkhead a ca...

Page 245: ...ETY VALVE ANEROID SWITCH 115 VAC 28 VDC UP DOWN DOWN DOWN GND DUMP FILTER UP ALT DN ALT NORMAL STATIC SOURCE ALTERNATE STATIC SOURCE CABIN ALTITUDE EMERGENCY CONTROL VALVE AUTO MANUAL CABIN PRESS SWITCH LH MAIN GEAR SQUAT SWITCH AIRBORNE GND AUTO DUMP SNs 24 100 THROUGH 24 103 BELOW 8 000 FT ABOVE ABOVE 10 000 FT 10 000 FT ABOVE 10 000 FT AIR BELOW 8 000 FT ABOVE 10 000 FT SNs 23 003 THROUGH 24 13...

Page 246: ...CABIN UNDER PRESS SWITCH CABIN PRESS 115 VAC FILTER UP ALT DN ALT NORMAL STATIC SOURCE ALTERNATE STATIC SOURCE CABIN ALTITUDE EMERGENCY CONTROL VALVE AUTO MANUAL AIRBORNE LH MAIN SQUAT SW ON GROUND DUMP CABIN PRESS SWITCH NORMAL STATIC SOURCE DUMP INTO TAILCONE CABIN SAFETY VALVE STATIC PRESSURE CABIN PRESSURE CONTROL PRESSURE LEGEND CABIN DUMP 28 VDC ON SNs 24 150 THROUGH 24 169 THE FILTER IS REM...

Page 247: ...ATE STATIC SOURCE CABIN ALTITUDE EMERGENCY SWITCH AUTO MANUAL UNDER CABIN PRESS SWITCH CABIN UNDER PRESS SWITCH CABIN PRESS CABIN SAFETY VALVE ANEROID SWITCH NORMAL STATIC SOURCE DUMP INTO TAILCONE CABIN SAFETY VALVE STATIC PRESSURE CABIN PRESSURE CONTROL PRESSURE LEGEND FILTER BELOW 8 000 FT ABOVE 10 000 FT CABIN DUMP SAFETY SWITCH L MAIN GEAR SQUAT SWITCH AIRBORNE GND NORM DUMP 28VDC INCR ALT Fi...

Page 248: ...LVE FILTER 115 VAC CHECK VALVE UP ALT DN ALT NORMAL STATIC SOURCE ALTERNATE SOURCE CABIN ALTITUDE MANUAL CONTROL VALVE AUTO MANUAL UNDER CABIN PRESS SWITCH CABIN UNDER PRESS SWITCH CABIN PRESS DUMP INTO TAILCONE PRESSURIZATION JET PUMP VENT INTO TAILCONE 28 VDC AIR BLEED AIR AIR GND GND TIME DELAY RELAY TIME DELAY RELAY 28 VDC DN GEAR CONTROL SWITCH AIRCRAFT 25 040 THROUGH 25 045 ONLY UP FILTER BL...

Page 249: ... AIR EXHAUST CONTROL VALVE CABIN ALTITUDE EMERGENCY SWITCH FRAME 5 REGULATED PRESSURE REGULATED VACUUM TIME DELAY RELAY GEAR CONTROL SWITCH CONDITIONED AIR DUCT UP DN 28 VDC REG VAC REG PRESS PRESSURIZATION MANIFOLD PRESSURIZATION JET PUMP FRAME 22 TO BLEED AIR MANIFOLD VENT INTO TAILCONE CABIN SAFETY VALVE C B A DUMP INTO TAILCONE REGULATED PRESSURE BLEED AIR REGULATED VACUUM LEGEND CONDITIONED A...

Page 250: ... BLEED switch es a CABIN AIR FLOW switch which selects maximum airflow a safety switch on some airplanes a cabin altimeter and differential pressure indicator a cabin vertical speed indicator and a cabin altitude manual con trol valve See Figure 12A 6 for a typical pressurization module Mode Selector Switch This switch labeled AUTO MAN selects either the automatic or manual mode of oper ation In A...

Page 251: ...a man ual cabin altitude control valve such as those installed on later airplanes and described below On SNs 23 030 through 24 229 and 25 003 and subsequent and as a retrofit on earlier air planes a manual cabin altitude control valve commonly called the cherry picker is pro vided to control the outflow valve if the auto matic pressurization control system fails This three position valve spring lo...

Page 252: ...84 186 187 and 189 and 25 003 through 026 and 028 a guarded safety or dump switch Figure 12A 8 installed on the pressurization module per mits depressurizing the cabin by opening the cabin safety valve On some airplanes this switch is deactivated by an aneroid switch above 10 000 feet and does not reset until the airplane descends below 8 000 feet Cabin Under Pressure Switch Above 10 000 feet cabi...

Page 253: ...models 24 24B and 25 CABIN AIR FLOW and AIR BLEED Switches AIR BLEED switches on SNs 23 029 and ear lier allow engine bleed air to flow to the bleed air manifold and then to the flow control valve Airplanes with a single AIR BLEED switch cause the flow control valve to move to the closed position when turned off On all air planes the CABIN AIR FLOW switch deter mines whether airflow is regulated t...

Page 254: ...r airplane electrical power fail ure cabin altitude can be manually controlled by selecting MAN position The MAN posi tion removes the cabin altitude controller rate sensor and amplifier from the system With the cabin altitude emergency valve cherry picker in the UP ALT position the reference chamber pressure bleeds to static This action opens the outflow path and allows the cabin to depressurize ...

Page 255: ...irplanes an emergency source of pressur ization bleed air is provided to increase the flow of air into the cabin in the event of a leak or other malfunction On SN 23 030 and subsequent emergency pressurization is provided by use of the wind shield defog system see Chapter 10 This is accomplished by directing bleed air from the bleed air manifold through the defog shutoff valve to the cockpit By cl...

Page 256: ...es auto matically D The bleed air shutoff and regulator valves close automatically 4 On all airplanes except SNs 23 003 through 23 030 if DC power fails A Pressurization control reverts to manual control B Pressurization control reverts to automatic control C Cabin pressure is not controlled D The cabin slowly depressurizes 5 The Flight Manual recommends use of the maximum airflow position A In ca...

Page 257: ... POWER SYSTEMS CONTENTS Page INTRODUCTION 13 1 GENERAL 13 1 HYDRAULIC SYSTEM OPERATION 13 2 HYDRAULIC SUBSYSTEMS 13 6 QUESTIONS 13 7 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 258: ...nd Prior and 25 180 and Prior Except 25 135 13 3 13 2 Hydraulic System Schematic SNs 24 297 and Subsequent and 25 135 181 and Subsequent 13 4 13 3 System Controls and Indicators Typical 13 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 259: ...es a positive sup ply of hydraulic fluid to both engine driven pumps and to the auxiliary pump The reser voir is pressurized to 10 psi by cabin air drawn in by an aspirator in the return line or to 20 psi by regulated engine bleed air pressure be ginning with SNs 24 297 and 25 181 The engine driven pumps are either constant volume or variable volume The pumps are supplied from lines connected to t...

Page 260: ...e first engine the HYDRAULIC PRESSURE indicator should be checked to verify engine driven pump operation When the second engine is started there is no change in pressure indication but output is doubled There is no positive indication that the second pump is operating properly there fore after landing shut down the engine started first and actuate a hydraulic subsystem If pressure drops slightly t...

Page 261: ...ROGEN PRESSURIZED AIR ELECTRICAL FILTER PRESSURE INDICATOR CHARGE VALVE ACCUMULATOR EFFECTIVITY 24D 285 AND SUBSEQUENT 25B 154 AND SUBSEQUENT ACCUMULATOR OVERBOARD VACUUM RELIEF GROUND SERVICE AUXILIARY PUMP PRESSURE SWITCH HYD PUMP 1 700 PSI FIRE FIRE AIR FROM PRESSURIZED CABIN JET PUMP VENTURI FIRE WALL SHUTOFF 28 VDC 28 VDC PRESSURE REGULATOR AIRPLANES WITHOUT GLARESHIELD LIGHTS NOT INSTALLED O...

Page 262: ...S BLEED AIR FILTER REGULATOR RELIEF VALVE 20 PSI VARIABLE VOLUME ENGINE DRIVEN PUMP 2 LEGEND PRESSURE SUPPLY RETURN AIR NITROGEN BLEED AIR REGULATED BLEED AIR ELECTRICAL FILTER ACCUMULATOR 850 PSI AIR OVERBOARD VACUUM RELIEF GROUND SERVICE AUXILIARY PUMP PRESSURE SWITCH HYD PUMP 1 700 PSI 28 VDC 28 VDC FIRE FIRE 650 PSI Figure 13 2 Hydraulic System Schematic SNs 24 297 and Subsequent and 25 135 18...

Page 263: ...ING MANUAL FlightSafety international ARMED ARMED LO HYD PRESS FIRE SHUTOFF VALVE INDICATOR PINHEAD LIGHT AIRPLANES EQUIPPED WITH GLARESHIELD WARNING LIGHTS AIRPLANES NOT EQUIPPED WITH GLARESHIELD WARNING LIGHTS Figure 13 3 System Controls and Indicators Typical ...

Page 264: ...subsystems is pre sented in Chapter 7 Powerplant Thrust Reversers Chapter 14 Landing Gear and Brakes and Chapter 15 Flight Controls Flaps and Spoilers 13 6 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 265: ...ndicator D All the above 4 On airplanes with glareshield warning lights the hydraulic shutoff valves are closed A With the FIRE switches B With the GEN switch in the OFF position C Automatically when the FIRE warn ing light comes on D With the BLEED AIR switches 5 On airplanes without glareshield warn ing lights the hydraulic shutoff valves are closed A With the BLEED AIR switches B With the GEN s...

Page 266: ...ergency Brakes 14 14 Parking Brakes 14 14 NOSEWHEEL STEERING 14 14 General 14 14 Operation Without Variable Authority SNs 24 263 and Prior and 25 103 and Prior 14 15 Operation With Variable Authority SNs 24 258 260 264 and Subsequent and 25 104 and Subsequent 14 16 MODEL 23 DIFFERENCES 14 17 Landing Gear 14 17 Brakes 14 19 QUESTIONS 14 20 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING...

Page 267: ... Emergency Gear Extension Lever 14 9 14 10 Emergency Landing Gear Extension 14 9 14 11 Brake System Schematic Model 25 Airplanes 14 11 14 12 Brake System Schematic Model 23 and 24 Airplanes 14 12 14 13 Nosewheel Steering System Airplanes without Variable Authority Steering 14 15 14 14 Nosewheel Steering System Airplanes with Variable Authority Steering 14 16 14 15 Landing Gear Control Panel Model ...

Page 268: ...gear extension and emergency braking The gear actuators incorporate integral downlocking devices downlock pins are not required Gear position indications are displayed on the instru ment panel The hydraulic brake system is controlled by four valves linked to the rudder pedals Hydraulic system pressure is metered to the self adjusting multiple disc brake assemblies in proportion to pedal deflection...

Page 269: ... inboard gear door is unlocked As each inboard door latches up during extension or retraction the correspond ing red light extinguishes Indications for gear down and locked up and locked and in transit conditions are shown in Figure 14 2 If the gear is extended with the emergency air system all three green lights and the two main gear red lights will be illuminated since both main gear doors will ...

Page 270: ...he horn Momentarily posi tioning the switch to MUTE silences the horn when thrust levers are retarded and the gear is not down and locked COMPONENTS Main Gear Each main gear consists of a conventional air hydraulic shock strut dual wheels torque arm squat switch main gear actuator inboard and outboard doors and an inboard door actuator Figure 14 3 14 3 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES ...

Page 271: ...eased by a hydraulic actuator With a full fuel load and no passengers or baggage aboard 3 to 3 1 2 inches of bright surface should be visible on the lower portion of the main gear strut Main Gear Wheel and Tires Each main gear wheel incorporates a fusible plug that prevents tire blowout caused by exces sive heat resulting from hard braking Tires must be monitored closely when tread has worn to the...

Page 272: ...f the strut is especially important With a full fuel load and no passengers or baggage aboard 5 1 4 to 5 3 4 inches of bright surface should be visible on the lower portion of the nose gear strut If the nosewheel is swiveled 180º from its normal position the cams may not be able to center the wheel prior to entering the wheel well Therefore the nose gear should be checked during the exteri or insp...

Page 273: ...ircraft antiskid system prevents brake application in flight Squat Switch Relay Box Functions Nose steering Pressurization Windshield overheat lights Inlet heater light Hourmeter Relay Panel Functions Windshield overheat Overheat light is con trolled by low limit thermoswitch on ground Nosewheel steering Nose steering is disabled in flight Inlet heater light Inlet heater light is disabled in fligh...

Page 274: ...ol valve to the retract position and hydraulic pressure is directed to retract the land ing gear Figure 14 6 The three green LOCKED DOWN lights extinguish and the nose gear red UNSAFE light illuminates When the gear has fully retracted the nose gear red UNSAFE light extinguishes When both main gear are fully retracted switches are actu ated and complete circuitry to energize the door control valve...

Page 275: ...s to energize the door control valve to the closed position Pressure closes the gear inboard doors Figure 14 7 which lock in position by spring tension on the door uplatches and the two main gear red UNSAFE lights extinguish 14 8 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Figure 14 7 Landing Gear Extended TO EMERGENCY BRAKES OVERBOARD GEAR EMERGEN...

Page 276: ...be pulled This will prevent inadvertent gear retraction subsequent to a successful exten sion The system is activated by depressing the emergency gear extension lever on the left side of the pedestal Figure 14 9 The lever has a ratchet to keep it in the down position once activated and can be raised only by pulling an adjacent metal tab while lifting the lever Figure 14 9 Emergency Gear Extension ...

Page 277: ...ess the antiskid system is activated The antiskid system permits stopping in the shortest possible distance for any given runway condition Parking brakes can be set by pulling a handle located on the left side of the throttle quadrant A pneumatic emer gency brake system is used to stop the airplane if hydraulic pressure is lost Neither antiskid pro tection nor differential braking is available dur...

Page 278: ...RBOARD EMER BRAKING VALVE GEAR EMERGENCY EXTENSION CONTROL VALVE SERVO ANTISKID VALVE SERVO 26 VAC BRAKE FUSE BRAKE FUSE TO RESERVOIR SOLENOID SHUTOFF SOLENOID SHUTOFF SQUAT SWITCH SQUAT SWITCH SERVO ANTISKID VALVE SERVO ANTISKID CONTROL BOX ANTISKID GEN ANTISKID TEST 25 204 AND PRIOR EXCEPT 197 25 184 AND PRIOR LEGEND SYSTEM PRESSURE METERED BRAKE PRESSURE RETURN EMERGENCY BRAKE AIR PRESSURE ELEC...

Page 279: ...ARD EMERG BRAKING VALVE GEAR EMERGENCY EXTENSION CONTROL VALVE ANTISKID VALVE ANTISKID VALVE ANTISKID VALVE 26 VAC BRAKE FUSE BRAKE FUSE ANTISKID PRINTED CIRCUIT BOARD ANTI SKID GEN TEST ANTISKID TEST 23 003 THROUGH 23 049 23 099 AND PRIOR 24 310 AND PRIOR ANTI SKID GEN LIGHTS 24 112 AND SUBSEQUENT LEGEND SYSTEM PRESSURE METERED BRAKE PRESSURE RETURN EMERGENCY BRAKE AIR PRESSURE ELECTRICAL MECHANI...

Page 280: ...n is lost on the associated wheel s Takeoff and landing data must be computed accordingly Operation Antiskid operation requires The ANTISKID switch must be on Each squat switch must be in the ground mode for its respective brake to function The parking brakes must be released The wheels must be rotating at least 150 rpm Above 150 rpm with the ANTISKID switch ON and brakes applied the control box r...

Page 281: ...y air bottle through four shuttle valves to the brake assemblies in proportion to handle movement A maximum of 600 psi may be applied Releasing the handle stops flow from the bottle and allows applied air pressure to be vented overboard releasing the brakes PARKING BRAKES Normal hydraulic system pressure from either engine driven pump or the auxiliary pump can be used to set the parking brakes Pul...

Page 282: ...rity nose wheel steering can be operated by the primary wheel master or steer lock switches Primary mode is engaged by depressing and holding either PRI STEER switch Figure 14 13 This provides steering capability of 40 to 50 in either direction for low speed taxi up to 10 knots Engaging the wheel master or steer lock switch es permits steering capability up to 10 in either direction Steering shoul...

Page 283: ...mands to the computer amplifier are controlled by wheel speed transducers The system reverts to maximum travel and should not be used above 10 knots if the following conditions exist Model 24 airplanes Both inboard green ANTI SKID GEN lights are off Model 25 airplanes Two or more of the following red ANTI SKID GEN lights are on Left inboard right inboard and right outboard Nosewheel steering is en...

Page 284: ... three gear down and locked the green LOCKED DOWN lights will be on and the UNSAFE light out A warning horn sounds if the thrust levers are retarded below 70 rpm with the gear up The TEST MUTE switch positioned to MUTE will silence the horn but the UNSAFE light will remain on After an emergency extension the three green LOCKED DOWN lights will illuminate and the red UNSAFE light will be off Priori...

Page 285: ...r down lines Pressure is applied simultaneous ly to the uplock actuator the door actuator and the gear actuator however the return fluid from the gear actuator is restricted by an orifice The uplock opens the inboard doors open and the gear slowly extends During the last few degrees of main gear travel mechanical linkage reverses the position of the directional control valves Pressure is applied t...

Page 286: ...in the parking brake valves cause diffi culty in parking brake release Depress the ped als slowly while holding the PARK BRAKE handle in the off position Antiskid Model 23 and SNs 24 100 and subsequent are equipped with the Goodyear antiskid system The system operates as described earlier in the chap ter with one exception model 23 airplanes do not have ANTI SKID GEN lights model 24 112 and subseq...

Page 287: ...tle through the anti skid control valves D Emergency air bottle 6 On airplanes without variable authority nosewheel steering the amount of steering available in either direction with the steer lock mode engaged is A 20º B 6 to 10º C 30º D 45º 7 On airplanes with variable authority nosewheel steering steering mode s available are A Steer lock only B Wheel master only C Primary only D Wheel master a...

Page 288: ... LOCKED DOWN lights are on B Flaps are extended below 25 C Gear is down and the thrust levers are above approximately 70 rpm D Gear is up and the thrust levers are below approximately 70 rpm 14 Illumination of a main gear red UNSAFE light may indicate A The corresponding main gear is not down and locked B The corresponding main gear is not up and locked C The corresponding main gear inboard door i...

Page 289: ...15 9 Rudder Trim 15 9 Aileron Trim 15 9 Pitch Trim 15 9 SECONDARY FLIGHT CONTROLS 15 12 Flaps 15 12 Spoilers 15 14 YAW DAMPERS 15 16 General 15 16 Single Yaw Damper System 15 16 Dual Yaw Damper System 15 16 STALL WARNING SYSTEMS 15 18 General 15 18 Stall Warning Indications 15 18 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 290: ...MKII Wing 15 21 MACH OVERSPEED WARNING STICK PULLER ALL AIRPLANES EXCEPT MODEL 23 15 22 General 15 22 Operation 15 22 Test 15 22 DIFFERENCES 15 22 Wheel Master Switch 15 22 Control Wheel Trim Switch 15 23 QUESTIONS 15 24 LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international 15 ii FOR TRAINING PURPOSES ONLY ...

Page 291: ... and Indicators 15 10 15 8 Flap System Schematic 15 13 15 9 Spoiler System 15 14 15 10 Spoiler System Schematic 15 15 15 11 Yaw Damper System 15 17 15 12 Angle of Attack Vane 15 18 15 13 Stall Warning System Airplanes with Standard Wing 15 19 15 14 Stall Warning System Airplanes with Century III Wing 15 20 15 15 Stall Warning System Airplanes with MKII Wing 15 21 FOR TRAINING PURPOSES ONLY LEARJET...

Page 292: ...ng the control surfaces to cockpit controls with no hydraulic or power boost A rudder aileron interconnect provides control coordination during turns The ailerons incorporate mechanical balance tabs to provide aerodynamic assistance Roll yaw and pitch trim systems are electrically oper ated and controlled The trim tabs are installed on the left aileron and the rudder The movable horizontal stabili...

Page 293: ... raise the nose of the airplane when MMO is exceeded Model 23 airplanes have overspeed warning but do not have a stick puller All flight control surfaces are shown in Figure 15 1 A flight controls gust lock Figure 15 2 is pro vided to prevent wind gust damage to the prima ry flight control surfaces When installed the lock holds full rudder and ailerons and full down elevators LEARJET 20 SERIES PIL...

Page 294: ...servo torquer is DC operated It is mechanically connected to the elevator control linkage through a capstan mechanism incorpo rating an electric clutch and a mechanical slip clutch Three flight control systems use the pitch servo to operate the elevators Autopilot When engaged the autopilot can alter noseup or nosedown attitude by commanding the servo to position the ele vator up or down as requir...

Page 295: ... TRAINING PURPOSES ONLY DOWNSPRING ASSEMBLY AUTOPILOT PITCH SERVO AFT ELEVATOR SECTOR FORWARD ELEVATOR SECTOR FORCE SENSOR BOB WEIGHT SNs 140 AND SUBSEQUENT ALL MODEL 25 AIRPLANES AND AIRPLANES MODIFIED FOR 45 000 FOOT OPERATION Figure 15 3 Elevator Control System Sheet 1 of 2 ...

Page 296: ... SERIES PILOT TRAINING MANUAL FlightSafety international 15 5 FOR TRAINING PURPOSES ONLY SNs PRIOR TO 24 140 EXCLUDING AIRCRAFT MODIFIED FOR 45 000 FOOT OPERATION Figure 15 3 Elevator Control System Sheet 2 of 2 ...

Page 297: ...on rudder interconnect assists turn coordination Figure 15 5 shows the aileron control system Roll Servo Autopilot Function Only The ailerons can also be positioned by the autopilot roll servo The roll servo is similar to the pitch servo but does not incorporate an elec tric clutch A mechanical slip clutch allows the pilot to override undesired roll servo inputs when the autopilot is engaged Balan...

Page 298: ...LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international 15 7 FOR TRAINING PURPOSES ONLY AUTOPILOT ROLL SERVOACTUATOR Figure 15 5 Aileron Control System ...

Page 299: ...PRIMARY YAW DAMPER SERVOACTUATOR SERVO SECTOR RUDDER BELLCRANK SECONDARY YAW DAMPER AILERON RUDDER INTERCONNECT AIRPLANES CERTIFIED FOR 45 000 FOOT OR HIGHER OPERATION SERIAL NUMBERS PRIOR TO 24 140 EXCLUDING AIRCRAFT MODIFIED FOR 45 000 FOOT OPERATION RUDDER SECTOR Figure 15 6 Rudder Control System ...

Page 300: ... planes and SNs 24 100 through 24 169 may have a single toggle or a rocker switch for rudder trim The rudder trim system is DC powered through the YAW circuit breaker AILERON TRIM Control Aileron roll trim is controlled with either con trol wheel trim switch located on the outboard horn of each control wheel Figure 15 7 Each control wheel trim switch is a dual function trim and trim arming switch ...

Page 301: ...S PILOT TRAINING MANUAL FlightSafety international 15 10 FOR TRAINING PURPOSES ONLY TRIM SWITCH ARMING SWITCH WHEEL MASTER SWITCH PILOT S CONTROL WHEEL COPILOT S SIMILAR Figure 15 7 Trim Systems Controls and Indicators ...

Page 302: ...e EMERG TRIM circuit breakers The emergency trim motor operates at approxi mately 1 2 the speed of the normal trim motor P TRIM Selector Switch The P TRIM pitch trim selector switch pro vides the normal and emergency mode selections Figure 15 7 In the NORM position normal pitch trim is available from both of the control wheel trim switches In the OFF position both trim motors and control circuits ...

Page 303: ...40º When extended the flaps are protected from excessive airloads by a 1 650 psi relief valve in the downline When the relief valve opens hydraulic pressure is relieved If the flap selector switch is left in the DN posi tion the control valve will remain energized hydraulically maintaining the flaps in that posi tion If hydraulic pressure is lost under these conditions a check valve near the contr...

Page 304: ...ystem Schematic FLAP ACTUATOR INTERCONNECT CABLE FLAP LIMIT SWITCH PRESELECT POSITION TRANSMITTER RELIEF VALVE EXTEND RETRACT FLAP CONTROL VALVE NORMAL HYDRAULIC SYSTEM PRESSURE RETURN STATIC MECHANICAL ELECTRICAL LEGEND AIRPLANES WITH MKII WING SNs 24 297 25 181 AND SUBSEQUENT OPTIONAL ON ALL AIRPLANES WITH MKII WING ...

Page 305: ...hen the SPOILER switch Figure 15 9 is positioned to EXT the spoilers begin to extend and the red spoiler light illuminates steady Full extension is approximately 40º Returning the switch to RET causes the spoilers to fully retract and the spoiler light to extinguish Spoiler deployment causes significant nosedown pitching and should be anticipated and offset with control pressure and pitch trim Whe...

Page 306: ...ety international 15 15 FOR TRAINING PURPOSES ONLY SOL SOL SPOILER CONTROL VALVE RETRACT EXTEND SHOWN IN EXTEND POSITION ACTUATOR ACTUATOR PRESSURE RETURN LEGEND SPOILER LH SPOILER RH SPOILER RESTRICTOR RESTRICTOR Figure 15 10 Spoiler System Schematic ...

Page 307: ...or depressing the YAW DAMPER OFF button on the autopilot con troller disengages the yaw damper DUAL YAW DAMPER SYSTEM All 25 series airplanes are equipped with dual primary and secondary yaw damper systems Each system is completely independent with its own rate gyro lateral accelerometer computer amplifier and damper servo Yaw deviation sig nals from the rate gyro and lateral accelerometer are pro...

Page 308: ...ightSafety international 15 17 FOR TRAINING PURPOSES ONLY PRIMARY YAW DAMPER SERVO SECONDARY YAW DAMPER SERVO SELECTOR SWITCH AUTOPILOT EFFORT INDICATORS AUTOPILOT FLIGHT CONTROLLER ALL MODELS 25 SERIES AIRPLANES Figure 15 11 Yaw Damper System ...

Page 309: ...operat ing range the yellow segment warns of an approaching stall and the red segment indicates that the angle of attack is at or just above aero dynamic stall On airplanes with the Century III wing the left and right ANGLE OF ATTACK indicators are controlled by their respective stall vane On airplanes with the MKII or standard wing each indicator is controlled by the vane on the opposite side of ...

Page 310: ...e autopilot to dis engage and the pitch servo to apply nosedown ele vator stick pusher When angle of attack decreas es below the stall point the pusher releases Stick shaker actuation occurs as the pointer sweeps 1 3 to 1 2 into the yellow segment of the indicator The stick pusher actuates as the indica tor moves into the red segment LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety internation...

Page 311: ...ane stall speed the autopilot disengages and the stick pusher applies nosedown elevator Testing of the system is accomplished on the ground with the stall warning test switch on the center pedestal Holding the switch to R TEST causes the pointer on the right ANGLE OF ATTACK indicator to sweep across the green segment As the pointer enters the yellow seg ment the right shaker actuates and the R STA...

Page 312: ...con ditions the computer amplifier disengages the autopilot and signals the pitch servo to apply nosedown elevator stick pusher When angle of attack decreases below the stall point the stick pusher releases Stick shaker actuation occurs when the pointer of the indicator is in the yellow segment The stick pusher actuates when the pointer is in the red segment and except for model 23 airplanes the S...

Page 313: ... should remain on at all times in flight except as indicat ed in the approved AFM With the stick puller inoperative speed is limited to 0 74 Mach on airplanes with a Century III wing On airplanes with a MKII or standard wing an inoperative stick puller limits the airplane to 30 000 feet or below TEST With the BATTERY switch es on test the stick puller by placing the L STALL WARNING switch on and a...

Page 314: ...t is possible to trim the ailerons with the autopilot engaged On airplanes with two speed trim any trimming action disen gages the autopilot completely LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international 15 23 FOR TRAINING PURPOSES ONLY ...

Page 315: ...lap position indicator will A Be powered by the emergency battery and indicate actual position of the flaps B Not be powered and will freeze at last flap position C Not be powered and will go to fullscale up deflection regardless of flap position D None of the above 6 The electrical power source for the stall warning system is provided by the A Battery bus B Battery charging bus C Main DC buses D ...

Page 316: ...er Operation 16 7 Stability System AFC SS 16 9 FC 110 AFCS Emergency Condition Procedures 16 9 FLIGHT DIRECTOR SYSTEM 16 9 General 16 9 Attitude Director Indicator ADI 16 11 Horizontal Situation Indicator HSI 16 11 Mode Selector 16 11 Operation 16 11 RVSM SYSTEM 16 13 General 16 13 System Control 16 13 Indications 16 13 Operating Procedures 16 14 QUESTIONS 16 18 FOR TRAINING PURPOSES ONLY LEARJET ...

Page 317: ... TEMP Gage 16 5 16 7 Autopilot Flight Controller 16 5 16 8 Control Wheel Switches Pilot s 16 6 16 9 Autopilot Effort Indicators 16 7 16 10 Flight Director Panels 16 9 16 11 ADI and HSI Symbology 16 10 16 12 Altimeter System 16 12 16 13 Air Data Panel 16 13 16 14 Air Data Panel Indications 16 14 16 15 Air Data Display Unit ADDU 16 14 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUA...

Page 318: ...his chapter GENERAL The air data system consists of the pitot static system the air data sensor if installed or au topilot altitude controller and the RAM AIR TEMP gage The automatic flight control system includes the autopilot and yaw damper The standard automatic flight control system installed on the Learjet 20 series is the Jet Electronics and Technology Inc JET FC 110 The yaw damper system op...

Page 319: ...Y VALVE REAR PRESSURE BULKHEAD STATIC PORT FORWARD PRESSURE BULKHEAD STATIC PORT INSTRUMENT ALTERNATE STATIC SOURCE VALVE AIRSPEED AND MACH INDICATOR PILOT ALTIMETER PILOT LH AFT STATIC PORT LH FWD STATIC PORT LH PITOT HEAD STATIC DEFECT CORRECTION MODULE ALT STATIC PORT NOSE COMPT PILOT S PITOT COPILOT S PITOT PILOT S STATIC LEGEND COPILOT S STATIC ALTERNATE STATIC OTHER STATIC NOTES 1 CENTURY II...

Page 320: ... of the cockpit Figure 16 2 Left and right PITOT HEAT switches are located on the pilot s subpanel See Chapter 10 Ice and Rain Protection for ad ditional information Condensate drains Figure 16 3 located near the left and right nose wheel well doors are provided for each pilot and static system on all airplanes SNs 24 138 and subsequent and all 25 models The static systems provide independent sour...

Page 321: ...ic system to an alternate source located on frame 5 For normal operation the lever remains down CLOSED for alternate air the lever is moved up OPEN When the ALTERNATE STATIC SOURCE valve is positioned to OPEN the pilot s static instruments are connected to an alternate port inside the unpressurized nose section See the AFM for corrections to be applied to the air speed and the altimeter when using...

Page 322: ...the following locations Roll under the floor in the forward part of the cabin Pitch in the vertical stabilizer left side of tail compartment above the bat teries on SNs 23 003 through 24 138 Yaw in the vertical stabilizer right side of tail compartment above the bat teries on SNs 23 003 through 24 138 Secondary yaw all 25 series in the tailcone The servos receive electrical signals from the autopi...

Page 323: ...eleased the roll and pitch axes of theAFCS automatically reengage main taining the new pitch attitude within limits and levels the wings If maneuver limits are ex ceeded and the switch is released the autopi lot will return the airplane to an attitude within the maneuver limits wings level and 15 pitch Previously engaged roll and pitch axes modes will be disengaged HDG ALT and NAV G S REV CRS 1 2 ...

Page 324: ...ot Stick Nudger Stick Puller Interface If the autopilot is engaged and the stick nudger or puller actuates any selected pitch mode will disengage and the autopilot will maintain a synchronous standby mode until the stick nudger or puller releases When the stick nudger or puller releases the autopi lot will maintain the existing pitch attitude Autopilot Effort Indicators An autopilot ef fort monito...

Page 325: ...noperative on VOR frequencies and disengaging the NAV mode also disengages the REV CRS function When NAV and or REV CRS buttons are de pressed the HDG mode will disengage Turning the turn knob out of detent will disengage NAV and or REV CRS modes Heading Mode The heading HDG mode button is pressed to activate the heading select function of the autopilot This mode com mands the autopilot to turn th...

Page 326: ...tallation is the Collins FD 108 Each flight director system includes an attitude director indicator ADI a horizontal situation indicator HSI a mode selector panel annunciators and course and heading select controls located on the HSI In addition the flight director has a pitch sync switch located on the control wheels The basic attitude reference mode is ener gized when AC and DC power is applied ...

Page 327: ...Y HORIZON LINE GLIDE SLOPE POINTER AIRPLANE SYMBOL RUNWAY SYMBOL BANK POINTER BANK INDEX RADAR ALTITUDE COURSE DISPLAY HEADING MARKER BUG AZIMUTH CARD LATERAL DEVIATION BAR CDI DISTANCE DISPLAY COURSE ARROW TO FROM ARROW GLIDE SLOPE POINTER AIRPLANE SYMBOL HEADING KNOB COURSE KNOB COMMAND BARS INCLINOMETER N 33 3 0 W 2 4 2 1 S 1 5 1 2 E 6 3 Figure 16 11 ADI and HSI Symbology ...

Page 328: ... been selected If selected mode s is subsequently disen gaged the command bars will stow Pitch hold is selected when the ALT button is pushed off HDG Mode When the HDG selector is pushed ON the command bars will display steering commands selected by the heading marker on the HSI NOTE When heading changes of greater than 135 are desired begin by moving the heading marker on the HSI 135 in the direc...

Page 329: ... MAIN BUS STBY ALTM RH MAIN BUS ADC AIU RH MAIN BUS ADC AIU L AC BUS 26 VAC 2 2 1 ANALOG INTERFACE UNIT AIU OUTPUT ANALOG SIGNALS FROM AIU USED BY AUTOPILOT LONG RANGE NAV SAT TAS INDICATOR 1 STANDBY ALTIMETER VIBRATOR 2 NOTE STBY ALTIMETER ILLUMINATED FROM EMERGENCY BAT STATIC SOURCE LH MAIN BUS 5 Figure 16 12 Altimeter System ...

Page 330: ...heads shall mean pitot static probes The pressurization static port has not changed in this configuration A standby altimeter pneumatic has been installed and plumbed to the aircraft existing shoulder static ports SYSTEM CONTROL The following circuit breakers are added to provide protection for the air data equipment ALT1 Is a 2 amp 28 VDC circuit breaker on the LH main bus It protects ADDU 1 ALT2...

Page 331: ...led on the slave ADDU when this occurs OFF Is on the ADDU LCD When this cap tion is in view all other indications will be blank This indicates an internal ADDU fault STBY Is on the ADDU LCD This annunci ator indicates that the ADDU is no longer ap plying a static source error correction and altitude reporting information is no longer available on this ADDU Refer to Figure 16 13 for the following V...

Page 332: ...mal conditions the corrections are negligible The pilot and copilot altitude position correc tion charts in the AFM Supplement are to be ap plied under all applicable flight conditions Altitude Reporting Altitude reporting may be supplied from ei ther ADDU Selecting ADC1 provides alti tude information from the pilot ADDU for either transponder Selecting ADC2 provides altitude information from the ...

Page 333: ...olating the copilot static air data source the pilot MASI indications should be considered suspect Selecting the L or R static port switch could also affect altitude position corrections as pre sented in the Performance section of the AFM Supplement Therefore the pilot and copilot position error correction charts should not be used when either the L or R static port switch positions are selected H...

Page 334: ... ground airspeed calibrations All altitude position correction charts All stall speed charts Low speed buffet boundary chart Takeoff safety speed V2 charts Enroute climb speed schedule Approach and landing climb speed charts Landing approach speed VREF chart 16 17 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 335: ...sing the spoilers C Flown with altitude hold off in se vere turbulence D Operated as outlined in A B or C 6 The basic attitude reference mode is energized when A AC and DC power is applied to the airplane B The AUTO PILOT engage button is depressed C The TEST switch is depressed D Both A and B above 7 When using autopilot back course mode the A Reciprocal of the front course must be set in the HSI...

Page 336: ...der 17 5 Overboard Discharge Indicator 17 5 OXYGEN PRESSURE Gage 17 6 Crew Distribution System 17 6 Passenger Distribution System 17 7 Oxygen Duration 17 9 DRAG CHUTE 17 10 General 17 10 Preflight 17 11 Operation 17 11 QUESTIONS 17 12 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 337: ...7 6 17 7 OXY MIC Panels Typical 17 7 17 8 Passenger Oxygen System Controls 17 8 17 9 Passenger Mask 17 8 17 10 Passenger Oxygen Compartment Door Manual Release 17 9 17 11 Tailcone Access Door and Drag Chute 17 10 17 12 Drag Chute Riser Attachment Hook 17 10 17 13 Drag Chute Handle 17 10 TABLE Table Title Page 17 1 Average Time of Useful Consciousness 17 9 FOR TRAINING PURPOSES ONLY LEARJET 20 SERI...

Page 338: ...nually at any altitude by the cockpit controls The system is primarily designed for use in the event of rapid decompression or pressurization system failure It is not designed for planned extended unpressurized flight at high cabin altitudes requiring the use of oxygen The optional drag chute is used to improve deceleration on the ground It is most effective when deployed at higher speeds but it c...

Page 339: ...national MANUAL SHUTOFF VALVE REGULATOR RELIEF VALVE 70 PSIG FILLER VALVE CREW OXYGEN MASK SOLENOID VALVE NORMALLY CLOSED ANEROID SWITCH MANUAL DOOR RELEASE MASK STORAGE DOOR RELEASE VALVE PASSENGER OXYGEN MASK OXYGEN CYLINDER CYLINDER RELIEF VALVE 3 350 PSIG DISCHARGE INDICATOR RELIEF VALVE 275 PSIG PRESSURE GAGE ON INSTRUMENT PANEL CREW OXYGEN MASK PASS OXY VALVE AUTO OFF NORMALLY OPEN AUTO PASS...

Page 340: ...GEN CYLINDER MANUAL SHUTOFF VALVE AND REGULATOR NORMALLY OPEN DISCHARGE INDICATOR PRESSURE GAGE ON INSTRUMENT PANEL CREW OXYGEN MASK PASS OXY VALVE AUTO OFF NORMALLY OPEN AUTO PASS MASK VALVE MAN AUTO NORMALLY CLOSED AUTO MASK STORAGE DOOR LANYARD PROVISION FOR OPTIONAL OXYGEN MASKS 24 201 THROUGH 24 288 25 039 THROUGH 25 182 EFFECTIVITY SUPPLY PRESSURE REGULATED PRESSURE LEGEND FLOW DETECTOR Figu...

Page 341: ...GEND MANUAL SHUTOFF VALVE AND REGULATOR NORMALLY OPEN FILLER VALVE CREW OXYGEN MASK SOLENOID VALVE ANEROID SWITCH NORMALLY CLOSED DOOR LATCH LANYARD ACTUATOR VALVE FLOW DETECTOR OXYGEN CYLINDER DISCHARGE INDICATOR PRESSURE GAGE ON INSTRUMENT PANEL CREW OXYGEN MASK PASS OXY VALVE AUTO OFF NORMALLY OPEN AUTO PASS MASK VALVE MAN AUTO NORMALLY CLOSED AUTO PASSENGER MASK STORAGE COMPARTMENT LANYARD Fig...

Page 342: ...ould always be left in the on open position The pilot should be aware that if the oxygen cylinder shutoff valve is closed oxygen pressure will still be read on the OXY PRESS gage in the cockpit During the interior preflight inspection ensure that the shutoff valve is open by checking for oxygen flow through both crew oxygen masks using the 100 or EMER position OVERBOARD DISCHARGE INDICATOR The ove...

Page 343: ...ted on the cockpit sidewalls Optional oxygen flow detectors may be installed in the mask oxygen lines NOTE Headsets eyeglasses or hats worn by crewmembers may interfere with the quick donning capabilities of the oxygen mask On 24E F 350 and subsequent and 25D 227 and subsequent crew masks are pressure demand with normal 100 and pressure positions that can be selected by the crew NOTE Use oxygen if...

Page 344: ...With EMER selected the regulator delivers 100 oxygen and maintains a slight positive pressure in the mask cup at all times for respiratory protection from smoke and fumes At 39 000 feet automatic pressure breathing is supplied Each mask assembly includes a microphone and has an electrical cord which is plugged into the OXY MIC jack on the respective OXY MIC panel Figure 17 7 located on each side p...

Page 345: ... if the cabin reaches 14 000 750 feet The aneroid switch opens the solenoid valve and deploys the passenger masks On SNs 24 256 and subsequent and 25 095 and subsequent it also illuminates the cabin overhead lights In the event of aircraft electrical failure automatic deployment of the passenger masks is not possible The oxygen solenoid valve requires DC power through the OXY VAL circuit breaker f...

Page 346: ...ne of the passenger mask lanyards after ensuring that the PASS MASK valve is closed AUTO If the doors open due to malfunction of the solenoid operated valve the PASS OXY valve must be turned off to permit stowage of the passenger masks The compartment doors can be opened manually for mask cleaning and servicing No smoking when oxygen is being used OXYGEN DURATION Before an overwater flight is made...

Page 347: ...oor Figure 17 11 The canister lid is released from the canister when the drag chute handle is pulled allowing the pilot chute to deploy The pilot chute then pulls the main chute canopy out of the canister The main chute riser attaches to the airplane at the chute control mechanism just forward of the canister Figure 17 12 The loop at the end of the main riser slips over a recessed metal pin which ...

Page 348: ...r keeper Check chute riser for proper routing and stowage as the tailcone access door is closed OPERATION As the nosewheel touches down the copilot on the pilot s command deploys the drag chute by squeezing the drag chute control handle and pulling it up to its full extension a pull force of approximately 40 pounds may be required With the chute deployed the pilot should keep the airplane well cle...

Page 349: ...feet B Passenger masks will automatically deploy in the event of electrical failure C Passenger masks will automatically deploy and the cabin overhead lights will illuminate if the cabin altitude reaches 14 000 feet D The aneroid controlled passenger mask drop valve is disabled 4 The OXY PRESS gage reads A Direct pressure of the cylinder B Electrically derived system high pressure C Direct pressur...

Page 350: ...is a pictorial walkaround It shows each item called out in the exterior power off preflight inspection The fold out pages at the beginning and the end of the walkaround section should be unfolded before starting to read The general location photographs may not show every checklist item however each item is portrayed on the large scale photographs that follow ...

Page 351: ...24 27 28 29 31 33 34 32 36 35 30 25 26 WALKAROUND 4 LEFT STALL WARNING VANE FREEDOM OF MOVE MENT LEAVE IN DOWN POSITION 3 LEFT PITOT HEAD COVER REMOVED CLEAR OF OBSTRUCTIONS 5 LEFT STATIC PORTS CLEAR OF OBSTRUCTIONS 1 PILOT S WINDSHIELD ALCOHOL DISCHARGE OUT LETS AND PILOT S DEFOG OUTLET CLEAR OF OBSTRUCTIONS 2 L E F T S H O U L D E R S TAT I C P O R T C L E A R O F OBSTRUCTIONS 6 SHOULDER STATIC ...

Page 352: ...UPLOCK FORWARD 9 RADOME ALCOHOL DISCHARGE PORT CLEAR OF OBSTRUCTIONS 10 RADOME AND RADOME EROSION SHOE CONDITION 12 RIGHT PITOT HEAD COVERS REMOVED CLEAR OF OBSTRUCTIONS 11 OXYGEN SUPPLY VALVE ON OXYGEN PRESSURE RELIEF DISC INTACT 14 RIGHT STATIC PORTS CLEAR OF OBSTRUCTIONS 13 RIGHT STALL WARNING VANE FREEDOM OF MOVEMENT LEAVE IN DOWN POSITION ...

Page 353: ... DRAIN VALVES 2 DRAIN 16 RIGHT SHOULDER STATIC PORT CLEAR OF OBSTRUCTIONS 17 COPILOT S WINDSHIELD DEFOG OUTLET CLEAR OF OBSTRUCTIONS 19 EMERGENCY EXIT SECURE 20 UPPER FUSELAGE ANTENNAE CONDITION 18 LOWER FUSELAGE ANTENNAE ROTATING BEACON LIGHT AND LENS CONDITION 21 ROTATING BEACON LIGHT AND LENS ON VERTICAL FIN CONDITION ...

Page 354: ...NDING LIGHT CONDITION 26 RIGHT MAIN GEAR WHEELS BRAKES AND TIRES CONDITION 23 FUEL CROSSOVER LEFT WING SUMP LEFT ENGINE FUEL RIGHT WING SUMP AND RIGHT ENGINE FUEL DRAIN VALVES DRAIN 27 STALL STRIP WING LEADING EDGE AND STALL FENCE CONDITION 24 RIGHT MAIN GEAR AND WHEEL WELL HYDRAULIC FUEL LEAKAGE AND CONDITION 28 RIGHT WING ACCESS PANELS UNDERSIDE OF WING CHECK FOR FUEL LEAKAGE ...

Page 355: ... WING CLEAR OF OBSTRUCTIONS 30 VORTEX GENERATORS OR BOUNDARY LAYER ENERGIZERS CONDITION 32 RIGHT TIP TANK CONDITION 31 RIGHT WING HEAT SCUPPER UNDERSIDE OF WING FORWARD CLEAR OF OBSTRUCTIONS 34 RIGHT TIP TANK SUMP DRAIN VALVE S TWO ON AIRPLANES PRIOR TO 24 181 AND 25 070 DRAIN 33 RIGHT TIP TANK RECOGNITION LIGHT AND LENS CONDITION ...

Page 356: ...ANK NAVIGATION LIGHT STROBE LIGHT AND LENS CONDITION 39 SCUPPER UNDERSIDE OF RIGHT WING AFT CLEAR OF OBSTRUCTIONS NO FUEL LEAKAGE 37 RIGHT TIP TANK FIN AND STATIC DISCHARGE WICKS 2 CONDITION 40 RIGHT AILERON CHECK FREE MOTION BAL ANCE TAB LINKAGE BRUSH SEAL CONDITION 38 RIGHT TIP TANK FUEL JETTISON TUBE CLEAR OF OBSTRUCTIONS 41 RIGHT SPOILER AND FLAP CONDITION ...

Page 357: ...NE DRAIN VALVE FUSELAGE TANK SUMP DRAIN VALVE DRAIN 42 RIGHT ENGINE OIL TANK FILLER CAP AND ACCESS DOOR SECURE 43 RIGHT ENGINE THRUST REVERSER CONDITION AND STOWED 46 LEFT AND RIGHT FUEL FILTER DRAIN VALVES DRAIN 47 FUEL VENT RAM AIR MAST DRAG CHUTE IN STALLED CHECKED 44 RIGHT ENGINE TURBINE EXHAUST AREA CONDITION CLEAR OF OBSTRUCTION ...

Page 358: ...LED CHECKED 49 TAILCONE ACCESS DOOR OPEN 52 TAILCONE INTERIOR CHECK FOR FLUID LEAKS SECURITY AND CONDITION OF INSTALLED EQUIPMENT 50 TAILCONE INTERIOR CHECK FOR FLUID LEAKS SECURITY AND CONDITION OF INSTALLED EQUIPMENT 51 TAILCONE INTERIOR CHECK FOR FLUID LEAKS SECURITY AND CONDITION OF INSTALLED EQUIPMENT 53 DRAG CHUTE CHECK FOR PROPER INSTALLATION ...

Page 359: ...AND SECURED 56 OXYGEN BOTTLE SUPPLY VALVE OPEN 65 FIRE EXTINGUISHER DISCS CONDITION 59 RIGHT VOR LOC ANTENNA CONDITION 60 VERTICAL STABILIZER RUDDER HORIZONTAL STABILIZER AND ELEVATOR CONDITION DRAIN HOLES CLEAR 61 STATIC DISCHARGE WICKS 6 ON HORIZONTAL STABILIZER 1 ABOVE NAV LIGHT 1 ON VERTI CAL FIN CONDITION 62 VERTICAL FIN NAVIGATION LIGHTS STROBE LIGHT AND LENS CONDITION 63 VLF H FIELD ANTENNA...

Page 360: ...ON AND STOWED DEE HOWARD 69 LEFT AILERON CHECK FREE MOTION BAL ANCE AND TRIM TABS LINKAGE AND BRUSH SEAL CONDITION 67 LEFT ENGINE DIPSTICK FILLER CAP AND ACCESS DOOR SECURE 70 LEFT TIP TANK FUEL JETTISON TUBE IF IN STALLED CLEAR OF OBSTRUCTIONS 68 LEFT SPOILER AND FLAP CONDITION 71 LEFT TIP TANK FIN AND STATIC DISCHARGE WICKS 2 CONDITION ...

Page 361: ...TIP TANK FUEL CAP CONDITION AND SECURE 76 LEFT TIP TANK CONDITION 74 LEFT TIP TANK SUMP DRAIN VALVE TWO ON AIR CRAFT PRIOR TO SNs 24 181 AND 25 067 DRAIN 77 LEFT WING HEAT SCUPPER UNDERSIDE OF WING FORWARD CLEAR OF OBSTRUCTIONS 75 LEFT TIP TANK RECOGNITION LIGHT AND LENS IF INSTALLED CONDITION 78 BOUNDARY LAYER ENERGIZERS IF INSTALLED CONDITION 79 VORTEX GENERATORS MISSING ...

Page 362: ...ING ACCESS PANELS UNDERSIDE OF WING CHECK FOR FUEL LEAKAGE 81 LEFT FUEL VENT UNDERSIDE OF WING IF INSTALLED PLUG REMOVED CLEAR OF OBSTRUCTIONS 84 LEFT MAIN GEAR AND WHEEL WELL HYDRAULIC FUEL LEAKAGE AND CONDITION 82 STALL STRIP WING LEADING EDGE CONDITION 85 LEFT MAIN GEAR LANDING LIGHT CONDITION 86 LEFT MAIN GEAR WHEELS BRAKES AND TIRES CONDITION ...

Page 363: ...WA 14 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international 87 LEFT ENGINE INLET CLEAR OF OBSTRUCTIONS AND CONDITION ...

Page 364: ...TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafetyinternational 59 47 60 61 62 63 55 54 53 52 51 50 49 46 42 45 41 40 39 38 37 56 57 58 43 44 73 67 66 64 48 65 68 69 70 71 72 Revision 01 ...

Page 365: ...WA 16 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafetyinternational ...

Page 366: ...1 APP 2 Fahrenheit and Celsius Temperature Conversion APP 2 APP 3 Inches to Millimeters 0 001 Inch to 10 Inches APP 3 APP 4 Weight Mass Ounces or Pounds to Kilograms APP 4 APP 5 Weight Mass Thousand Pounds to Kilograms APP 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international ...

Page 367: ...APP 1 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Table APP 1 CONVERSION FACTORS ...

Page 368: ...APP 2 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Table APP 2 FAHRENHEIT AND CELSIUS TEMPERATURE CONVERSION ...

Page 369: ...APP 3 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Table APP 3 INCHES TO MILLIMETERS 0 0001 INCH TO 10 INCHES ...

Page 370: ...APP 4 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Table APP 4 WEIGHT MASS OUNCES OR POUNDS TO KILOGRAMS ...

Page 371: ...APP 5 FOR TRAINING PURPOSES ONLY LEARJET 20 SERIES PILOT TRAINING MANUAL FlightSafety international Table APP 5 WEIGHT MASS THOUSAND POUNDS TO KILOGRAMS ...

Page 372: ...i FOR TRAINING PURPOSES ONLY ANNUNCIATOR PANEL The Annunciator Panel section presents a color representation of all the annunciator lights in the airplane Please unfold page ANN 1 to the right and leave it open for ready reference as the annunciators are cited in the text ...

Page 373: ...ICE R ANTI ICE L TIP PUMP R TIP PUMP FUS PUMP IGNITION STALL WARNING SYSTEM 1 OFF STALL WARNING SYSTEM 2 OFF L GEN OFF L FIRE R GEN OFF E M E R G E N C Y O F F L R ANTI SKID SYS TEST HDG OR NAV ARM NAV CAPT REV GS ARM GS CAPT EXT MON MON FM Z OM MM FM Z UNSAFE LOCK DOWN BRT TEST MUTE GEAR UP OM MM ENGAGE AIR IGN OFF GA HDG NAV ARM NAV CAPT REV GS ARM GS CAPT EXT GA L ENG ICE L FUEL PRES R FIRE R E...

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