CESSNA AIRCRAFT
COMPANY
SINGLE ENGINE
STRUCTURAL REPA
IR MANUAL
WING FUEL BAY REPAIRS
1. Preparing Dama
ged Area In Wing Fuel Bay for Repair
A. Before performing any maintenance in fuel bay area, it will be necessary to defuel and purge the fuel
bay. To defuel and purge the fuel bay, proceed as follows:
WARNING: During all fuel system servicing procedures, fire fighting
equipment must be available.
WARNING: Always ground airplane prior to performing any maintenance of the
fuel system.
WARNING: Avoid drainag
e from residual fuel held in disconnected fuel lines;
this accumulation constitutes a fire hazard.
WARNING: Use NS-40 (RAS-4) (Snap-On Tools Corp., Kenosha, Wisconsin),
MIL-T-83483 (thread compound, anti- seize, graphite petrolatum),
or engine oil
as a thread lubricant or to seal leaking connections.
Apply sparingly to all but first two threads of male fittings, being
careful not to allow entry of compound into fuel system.
NOTE: Covers or ca
ps should be installed on lines and fittings to prevent entry of foreign material,
and to prevent damage to threads.
(1) Ground airp
lane to a suitable ground stake.
(2) Ensure airplane battery switch is in OFF position.
(3) Turn fuel selector valves to OFF position
(4) Remove fuel fi
ller cap on bay that is to be defueled; insert defueling nozzle.
(5) Remove as much fuel as possible through filler opening.
(6) Remove drain valves from bottom side of fuel bay and drain remaining fuel into a clean, open
container. U
se defueling nozzle to remove fuel from container.
(7) If necessary, repeat procedures for opposite wing.
WARNING: Purge fuel bays with an inert gas (argon or carbon dioxide)
prior to rep
airing fuel leaks to preclude possibility of
explosions.
(8) Insert inert gas supply hose into fuel filler opening.
(9) Allow gas to flow into bay for several minutes to remove all fuel vapors. Since argon or carbon
dioxide are
heavier than air, these gasses will remain in bay during repair. Non-sparking tools
shall be used to make repairs (air motors, plastic scrapers, etc.).
NOTE: Portable va
por detectors are available to determine presence of explosive mixtures
and are calibrated for leaded fuel. The detectors can be used to determine when it is
safe to make repairs.
NOTE: During structural repair, parts must be predrilled, countersunk or dimpled, and
cleaned before being sealed and positioned for final installation.
(10) Remove all existing sealant from area to be sealed, leaving a taper to the remaining sealant.
The taper will allow a scarf bond and a continuous seal when the new sealant is applied.
NOTE: The best method of removing sealant is with a chisel-like tool made of hard fiber or
plexiglass. Remaining sealant can be removed with aluminum wool. Steel wool or
sandpaper
must not be used.
57-11-00 Page 801
© Cessna Aircraft Company Jun 1/2005
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