This section discusses the three kinds of sealants in general use in
Army aviation and sealant repair. The information in this section is
important because some areas of an airframe structure are sealed
compartments used for fuel tanks and others are for crew and
Fuel tank compartments are tightly sealed to keep
fuel vapors from coming into the aircraft's interior.
passenger compartments are sealed tightly to permit controlled
ventilation. Because it is not possible to seal these areas tightly
enough with only a riveted joint, a sealing compound is used.
Sealants are also used to add aerodynamic smoothness to such exposed
surfaces as seams and joints in the fuselage and wings.
KINDS OF SEALANTS
Rubber, sealing compound, and special seals are the three kinds of
sealants generally used in Army aviation.
The applicable technical
manual for the aircraft being worked on must be consulted for details
on sealer application. The paragraphs that follow describe each kind.
Rubber Seals. Rubber seals are used at all points where the seal
is broken frequently for necessary repairs.
Examples of such
locations are canopies and access doors.
Because the seal must be
continuous around the joint, it cannot be repaired.
anytime a rubber seal is damaged or broken for repairs, it must be
Sealing Compounds. Sealing compounds are used at points where the
seal is seldom broken except for structural maintenance or part
replacement, as with riveted lap and butt seams and joints. They can
also be used to fill gaps or holes up to 1/16 inch in width.
Special Seals. Special seals are required to pass cables, tubing,
and tubing are passed through sealed-area bulkheads by using such
bulkhead fittings as cannon plugs for wiring and couplings for
tubing. These fittings are sealed to the bulkhead, and the wires and
tubes are fastened to them from each side.
All seals of moving
components, such as flight controls, are subject to wear. Therefore,
care must be taken when they are installed, and they must be
All surfaces that are to be sealed must be thoroughly cleaned to
ensure maximum adhesion between the surface and the sealant.
approved strippers, cleaners, and sealants can be used; and, even
though approved, the stripper compound must be used with care.
Details on cleaning and the sealant to be used can be found in the