The method of opening the hatch from the ex-
terior varies with airplane model:
• On 23 models, exterior opening requires
that the top center screw be removed
and punched out. The hatch then can be
pushed inside.
• On 24, 24B, and 25 models, the exterior
latch must be raised up, then pushed in
to release the hatch. The hatch then can
be pushed inside.
• On 24D, E, F, and 25B, C, and D mod-
els, exterior opening is accomplished
by depressing a PUSH button above the
window, which releases a handle. The
handle must then be turned in the direc-
tion of the arrow stamped on the handle.
The hatch then can be pushed inside.
Windows
Windshield—23 Model
The windshield is divided into two sections—
the pilot’s and copilot’s halves—and consists
of two panes of acrylic plastic (Figure 1-12).
The outer pane is .460 inches thick and the
inner pane is .188 inches thick, with an air sep-
aration between the panes. A dehydrator lo-
cated under the copilot’s seat removes moisture
from conditioned cabin air before it is routed
between the panes. The dehydrator and plastic
line must be kept in proper operating condition
to prevent moisture, dust, or smoke from col-
lecting on the inner surfaces of the panes.
Windshield—All 24 and 25 Models
The windshield is divided into two sections—
the pilot’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 apart and sealed airtight by a spacer.
Passenger Windows—All Other Models
Six to nine small, dual-pane, acrylic plastic
windows are installed in the airplane, including
the emergency exit hatch window (Figure 1-13).
Cleaning of Windows
The following precautions should be taken
when cleaning airplane windows:
• Remove loosely adhering dirt and grit from
the window by flushing with clean water.
• Wash with nonabrasive soap and water.
A soft, thoroughly clean cloth, sponge,
or chamois may be used in washing, but
only as a means of carrying the soapy
water to the plastic. Go over the surface
only with the bare hand so that any abra-
sive can be quickly detected and re-
moved before it scratches the plastic
surface.
• Remove oil and grease by rubbing lightly
with a cloth wetted with aliphatic naptha.
• Dry the surface with a clean, damp cham-
ois. A clean, soft cloth or tissue may be
used if care is taken not to rub the plas-
tic after it is dry.
1-12
FOR TRAINING PURPOSES ONLY
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
Figure 1-12. Windshield (Typical)
