Mooney M20TN, Service And Maintenance Manual

Page: 206 / 1169

MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Page
Date
14
2006
Rev Date
9. Map Light. A switch/rheostat, located on the con-
trol wheel, controls the map light and brightness.
24--36--00 -- LANDING GEAR CIRCUITS
1. Limit switches and relays operate the reversible
landing gear actuator motor. A landing gear, air pres-
sure, safety switch, actuated by pitot air pressure, pre-
vents landing gear retraction until a safe flying speed is
attained. The landing gear control switch operates ac-
tuator motor through the safety switch and relays.
When the landing gear control switch is UP and a safe
flying speed has been attained, the safety switch
closes to activate the control relay and the actuator
starts. As the gear reaches the up and locked position,
a mechanical up stop opens the limit switch and the ac-
tuator stops. When landing gear control switch is
placed in the DOWN position, the gear motor down--
relay closes and the actuator starts. When the gear
reaches the down--and--locked position, a mechanical
down stop opens the limit switch and the actuator
stops. The gear--up limit switch controls the landing
gear un--safe light. The RED light comes on when the
gear is in transit. The green light comes on when the
gear reaches the down--and--locked position; the gear--
down limit switch controls the green gear--down light.
The GEAR DOWN annunciator light is dimmed when-
ever navigation lights are ON.
2. Gear Safety By--Pass Switch. The gear will not re-
tract if airspeed above the set limit has not been at-
tained when the gear handle is placed in the UP posi-
tion. A warning horn will sound and both “GEAR
DOWN” and “GEAR UNSFE” lights will illuminate.
PUSH and HOLD the RED BUTTON SWITCH beside
the landing gear handle until the gear is up and both
lights go OUT. PULL the “GEAR CONT” or “GEAR
RELAY” circuit breaker to stop warning horn. Reset cir-
cuit breaker prior to extending gear.
24--37--00 -- FUEL SYSTEM CIRCUITS
The fuel system has an electric fuel boost pump. The
fuel quantity indicating system is comprised of two
transmitters in each fuel tank (inboard and outboard)
and is displayed on the G1000 screen.
1. Fuel Pump Circuit. -- A single, auxiliary electric boost
fuel pump is controlled by two switches and a relay (lo-
cated behind PFD mtg. on Air Data Computer bracket).
The LOW BOOST switch is utilized for engine starting
procedures and to purge fuel vapors from system dur-
ing high temperature conditions, either heat soak con-
ditions or high OAT.
The HIGH BOOST (guarded switch) is utilized for use if
the engine driven fuel pump malfunctions and will pro-
vide sufficient fuel for partial power operation of the en-
gine.
2. Fuel Quantity is displayed on the G1000 screen.
Changes in fuel level vary fuel quantity transmitter re-
sistance (two in each tank work in series with each oth-
er) that operates the fuel quantity gauges. The Master
Switch activates the fuel quantity indicating system.
Refer to Garmin G1000 Service and Maintenance
manual and/or an Authorized Garmin Service Center.
3. Fuel Flow System -- A turbine type, fuel flow trans-
ducer is installed in the fuel line between the engine
driven fuel pump and the throttle body control of the fuel
injector system. The fuel flow is displayed on the G1000
by electrical impulses from the transducer to indicate
current fuel flow at a given power setting.
24--38--00 -- MISCELLANEOUS CIRCUITS.
1. Standby Electric Gyro -- The Standby Electric Gyro
(Artificial Horizon) is a flight instrument which operates
from an electrical power source. Used as an emergen-
cy attitude reference in the event of aircraft power fail-
ure
2. Heated Pitot Tube -- A circuit breaker switch con-
trols the pitot tube heater.
3. Hour Meter -- The hour meter operates from the air-
speed switch. An optional Hobbs meter may be
installed.
4. Accessory Socket. A 14 volt Accessory Socket is
mounted in the right instrument panel.
5. Emergency Lighting -- A circuit will allow standby
instruments to energize and illuminate when emergen-
cy lighting is in use.
6. Ice Light (if equipped) -- Lighting to alert the pilot of
ice formation on surfaces of an aircraft.
24--39--00 -- TROUBLESHOOTING CHARTS
24--39--01 -- RESERVED
24--39--02 -- RESERVED
24--36--00
AUGUST 2010