FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 3. Fiberglass and Plastics | 3. Transparent Plastics | 3-27. Installation Procedures
AC 43.13-1B
9/8/98
temperatures, resistance to discoloration when
exposed to sunlight, surface checking, etc. In
formation on these properties is in
MIL-HDBK-17A, Plastics for Flight Vehicles,
Part IITransparent Glazing Materials, avail
able from the Government Printing Office
(GPO). These properties are considered by
aircraft manufacturers in selecting materials to
be used in their designs and the use of substi
tutes having different characteristics may result
in subsequent difficulties.
c. In bolted installations, use spacers,
collars, shoulders, or stop-nuts to prevent
tightening the bolt excessively. Whenever
such devices are used by the aircraft manufac
turer, retain them in the replacement installa
tion. It is important that the original number
of bolts, complete with washers, spacers, etc.,
be used. When rivets are used, provide ade
quate spacers or other satisfactory means to
prevent excessive tightening of the frame to
the plastic.
3-27. INSTALLATION PROCEDURES.
When installing a replacement panel, use the
same mounting method employed by the
manufacturer of the aircraft. While the actual
installation will vary from one type of aircraft
to another, consider the following major prin
ciples when installing any replacement panel.
a. Never force a plastic panel out of
shape to make it fit a frame. If a replacement
panel does not fit easily into the mounting,
obtain a new replacement or heat the whole
panel and reform. When possible, cut and fit a
new panel at ordinary room temperature.
b. In clamping or bolting plastic panels
into their mountings, do not place the plastic
under excessive compressive stress. It is easy
to develop more than 1,000 psi on the plastic
by over-torquing a nut and bolt. Tighten each
nut to a firm fit, then back the nut off one full
turn (until they are snug and can still be rotated
with the fingers).
d. Mount plastic panels between rubber,
cork, or other gasket material to make the in
stallation waterproof, to reduce vibration, and
to help to distribute compressive stresses on
the plastic.
e. Plastics expand and contract consid
erably more than the metal channels in which
they are mounted. Mount windshield panels to
a sufficient depth in the channel to prevent it
from falling out when the panel contracts at
low temperatures or deforms under load.
When the manufacturer’s original design per
mits, mount panels to a minimum depth of
1-1/8 inch, and with a clearance of 1/8 inch
between the plastic and bottom of the channel.
f. In installations involving bolts or riv-
ets, make the holes through the plastic over
size by 1/8-inch diameter and center so that the
plastic will not bind or crack at the edge of the
holes. The use of slotted holes is also recom
mended.
3-28.3-39. [RESERVED.]
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