personnel inspect such areas, they should also inspect
all sections in the cooling air path, giving special
attention to obstructions and crevices where salt
deposits may build up during marine operations.
Corrosion must be checked in its early stages and paint
touch-up and hard-film, preservative coatings must be
Jet exhaust deposits are very corrosive. These
deposits are particularly troublesome where gaps.
seams, hinges, and fairings are located down the
exhaust path, and where the deposits may be trapped
and not reached by normal cleaning methods. When
inspecting these surfaces, maintenance personnel
should give special attention to the areas indicated in
figure 4-23. Maintenance personnel should also
include in their inspection procedures the removal of
fairings and access panels located in the exhaust path.
JATO, Rocket, and Gun Blast Areas
Surfaces located in the path of JATO, rocket, and
gun blasts are particularly subject to corrosive attack
and decay (fig. 4-24). In addition to the corrosive
effect of the gases and exhaust deposits, protective
finishes are often blistered by heat and blasted away
by high-velocity gases. Also, spent shell casings or
solid particles from gun and rocket exhausts abrade
finishes. Maintenance personnel should watch these
areas for corrosion and clean the finishes carefully
after firing operations.
Bilge areas are common trouble spots on all
aircraft. One example of a bilge area is the engine bay
area. Bilge areas are natural collection points for
waste. hydraulic fluids, water, dirt, loose fasteners,
drill shavings, and other debris. Oil puddles often
mask small quantities of water, which settle to the
bottom and set up hidden corrosion cells. Keeping
bilge areas free of extraneous material, including oil,
is the best insurance against corrosion.
Wheel Wells and
The wheel well area probably receives more
punishment than any other area on the aircraft. It is
exposed to mud, water, salt, gravel, and other flying
debris from runways during flight operations. It is
open to salt water and salt spray when the aircraft is
parked aboard ship. Because of the many complicated
shapes, assemblies, and fittings in the area, complete
coverage with a protectile paint film is difficult to
attain. Because of the heat generated from braking,
Figure 4-23.Exhaust trail corrosion points.