THRUSH AIRCRAFT, INC – MODEL S2R R1340
AIRCRAFT MAINTENANCE MANUAL
Effective: 01/01/08
5-11
A. Remove the cover plates on upper
surface of wing to repair the tank
leak. Determine the exact location of
the leak source as precisely as
possible.
B. Clean the general area of the leak
thoroughly. Better to clean too large
of an area than too small. If the
source of the leak is known exactly,
seal it with B type sealer. Apply an
even coat of A type sealant over the
leak repair plus 3” around it with a stiff
clean brush.
C. If only the general area of the leak is
known, a larger area should be
cleaned (at least 12” past wherever
the leak is suspected) and the area
coated with type A sealant.
D. Allow the sealer to dry overnight.
E. After drying, the sealer should be
checked for air bubbles or thin spots.
Additional sealer should be applied
where necessary.
F. Reinstall the cover plates on wing
upper surface.
RESEALING AFTER COMPLETE SKIN
REMOVAL
To reseal the fuel tanks after removing or
repairing the wing skin, proceed as
follows:
A. Prior to installing the wing tank skin,
vacuum tank area thoroughly to
remove all particles of dried sealant,
dirt or other foreign matter. Allow the
sealant to cure for 16 hours or more.
B. The entire tank interior should be
cleaned to remove fuel residue. All
surfaces that will receive sealant shall
be cleaned again and etched.
C. Apply type B sealant to all areas of
contact between the skin and ribs,
spars, intercostals and other skins.
D. Wet rivet the wing tank skin in place
Smooth out sealant squeezed out to
make fillet seals at all junctions.
E. Coat the entire replaced skin and all
supporting structure plus a 3” band
around it with type A sealant.
F. Reseal cover plates and fuel quantity
transmitter mounting with fuel proof
sealer.
G. To prevent water and chemical entry
into wing and empennage skin joints
and edges, fillet seal them by
applying a small bead of fuel proof
sealant to all skin edges, joints, and
overlaps. The fillets can be painted
after sealer has dried.
H. Pressure check fuel tank per the
following instructions.
FUEL TANK PRESSURE CHECK
REQUIRED EQUIPMENT
A. Pneumatic shut-off valve with an
operator that requires multiple turns
to open. This is so that pressure
can be applied gradually.
B. Manometer
board
per figure 5-5.
(can be locally fabricated).
C. Suitable flexible hose from shut-off
valve to wing fuel tank/system
outlet.
D. Suitable flexible hose from wing fuel
tank vent to manometer board.
E. Worm clamps for attaching hoses to
wing fuel tank outlet and wing fuel
tank vent.
F. Suitable leak detection fluid and
applicator.
FUEL TANK SET-UP
When a wing fuel tank is being pressure
tested, one of the fuel outlets must be
capped, while the other is left open.
Prepare both outlet line and the fuel tank
vent line for connection to the
manometer board.
Ensure that all access hole covers are
installed properly, drain plugs are tight,
and the fuel filler cap is closed tightly.
