Leak Sealing - THRUSH S2R – G10 Maintenance Manual

AIRCRAFT MAINTENANCE MANUAL
Figure 5-4: Proper Application of Fuel Proof Sealant
When working with fuel tank sealer,
cleanliness is mandatory. Something as
simple as a fingerprint or a piece of lint can
result in a fuel tank leak down the road.
Rule one is to get all the cutting, drilling,
grinding, etc. out of the way before you
start trying to seal. Having to add a hole
after sealing has begun is a recipe for a
leak. Deburr all holes and edges and
clean out all shavings.
Faying seals involve a layer of "B" type
sealant between mating surfaces. Sealant
is spread on both mating surfaces before
joining. If working on mating surfaces that
are pried apart, use a pressure applicator
to be sure sealant gets all the way
between the mating surfaces where they
are still attached. When the fasteners are
tightened, starting at one end and working
to the other, the faying sealant is squeezed
out along the edges. If a small bead does
not squeeze out, not enough sealant was
used. Ideally the faying seal should end
up .015" or about 1/64" thick.
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THRUSH AIRCRAFT INC – MODEL S2R G10
Fillet seals are continuous lines of sealant
along the joints between two parts. The
bead squeezed out from the faying seal is
a good start, and may be sufficient when
formed into a fillet. If the bead material is
not enough to get the coverage thickness
specified in Figure 5-4, add more "B"
sealant. Use a tool or a latex gloved finger
for smoothing, not a bare finger. Do not try
to clean up excess sealant with solvent.

LEAK SEALING

Determine the approximate location of the
leak by visual inspection through the cover
plates in the lower surface of the wing.
After leak area is determined, drain all fuel
from affected tank.
defueling procedures.
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.
See Section 2 for
Effective: 03/26/2010