The sweptback vertical stabilizer is formed by
five spars, which are securely connected in the
tailcone. The vertical stabilizer is the mount-
ing point for the rudder and horizontal stabi-
lizer. At the lower leading edge of the vertical
stabilizer is a dorsal fin which houses a ram-
air scoop. Model 25 series airplanes have the
oxygen bottle located within the dorsal fin.
The horizontal stabilizer is a sweptback, full-
span unit, constructed around five spars. It is
attached to the vertical stabilizer at two points:
• The center aft edge attaches to a heavy-
duty hinge pin.
• The center leading edge attaches to an
electrically operated jackscrew to pro-
vide pitch axis trim.
AIRPLANE SYSTEMS
The following is a brief introduction to the
major airplane systems on the Learjet 20 se-
ries airplanes. Detailed descriptions of these
systems are contained within the individual
chapters of this training manual.
ELECTRICAL POWER
SYSTEMS
DC electrical power is provided by two engine-
driven generators. Backup power is supplied
by two 24-volt batteries. The airplane is
equipped with one or more emergency batter-
ies. The airplane also has the capability of ac-
cepting DC power from a ground power unit.
AC power is provided by either two or three
solid-state static inverters.
LIGHTING
Interior lighting is supplied for general cock-
pit use and for instrument illumination. Cabin
lighting consists of overhead lighting, individ-
ual passenger positions, and cabin baggage
compartment lighting.
Exterior lighting includes the combination
landing-taxi light on each main gear, naviga-
tion lights, anticollision lights, 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 center instrument panel. Airplanes with-
out glareshield warning lights have a readout
panel on the instrument panel. Unless retro-
fitted, these include airplanes SNs 23-003
through -099, 24-100 through -155, and 25-003
through -009.
FUEL SYSTEM
Fuel is contained in integral wing tanks, tip
tanks, and in a bladder fuselage tank just aft
of the rear pressure bulkhead on all models ex-
cept the 24E. The 25C model is a long-range
version with a larger fuselage tank. Fueling is
accomplished through filler caps in the top of
each tip tank. To fill the fuselage tank, fuel
must be transferred from the wing tanks.
POWERPLANT
T h e a i r p l a n e i s p ow e r e d b y t wo G e n e r a l
Electric CJ-610 series, single-rotor, axial-
flow turbojet engines. The engines are in-
stalled in pylon-mounted nacelles on each
side of the aft fuselage. An engine-driven
starter-generator is installed in each engine to
provide engine starting and furnish DC power
to the electrical system. Engine bleed air is
used for cabin pressurization and heating,
windshield defogging, wing anti-ice, and en-
gine front frame anti-icing.
All Learjet 20 series airplanes are equipped
with engine fire detection and fire-extinguish-
ing systems except model 23 which has detec-
tion only. The systems include detection circuits
which give visual warning in the cockpit and
1-16
FOR TRAINING PURPOSES ONLY
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
