Bell OH-58 C, Technical Manual

Page: 230 / 333

TM 55-1520-228-BD
FUEL SYSTEMS
2. Once step 1 of this section has been
completed, locate the damage; enlarge the
wound in the tank to no more than 3
inches in diameter by using a knife or
scissors.
Remove all frayed fabric and
damaged inner lines.
3. Abrade the inner lines or inner
surface at least 1/2 inch beyond the
enlarged hole, preferably more if con-
ditions permit.
Abrade the outer sur-
face to a minimum of 4 inches from the
enlarged area.
(NOTE: If the fraying
fibers are too numerous, trim the fiber
with scissors.)
4. Clean the abraded areas using towels
soaked in solvent.
5. Cut a fabric patch 4 inches in
diameter or large enough to extend at
least 1 inch beyond the damaged area and
add a 1/2 inch hole in the center.
Soak
the patch in solvent.
6. Mix the adhesive per option 2
instructions, step 5, and extrude into a
plastic cup. (NOTE: Adhesive can be
used between 20° through -120°, but must
be warmed to room temperature prior to
mixing and be mixed at room temperature.
Pot life of adhesive is approximately 25
minutes at 70°F.)
7. Apply adhesive to inner liner using
finger to swab cement around the wound.
Apply adhesive to concave surface of the
rubber plug (this is the surface the
cord is attached to). Refer to Figure
12-4 for rubber plug assembly.
NOTE
Use adhesive as required, retain
some for finishing the outside of
the cell repair.
8. Fold the rubber plug and insert it
through the hole in the cell. (NOTE:
Retain cord to prevent loss of plug in
the cell.)
9. Pull the plug into position and
rotate it in position to smooth out the
adhesive interface. Center the plug on
the wound.
10. Apply a layer of adhesive 4 inches
in diameter around the wound on the out-
side and fill in the wound with adhe-
sive. (NOTE:
There must be a minimum
of a 1/2 inch bond.)
11. Apply the solvent soaked fabric
patch to the outside surface by passing
the cord through the hole in the patch
and position the patch over the wound.
Smooth the patch into the adhesive.
12. Pull the cord and tape to the
structure keeping a slight tension.
13. Do not disturb the repair for a
minimum of 30 minutes, and let cure two
hours before refueling. Cut the string
and plug stem without disturbing the
repair.
14. Tighten drain valve and install
cover plate.
15. Refuel the aircraft.
16. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
OPTION 4. Two Plane Repair. Damage to
a two plane area will be repaired in the
same manner described in option 3,
except the hole should not be enlarged
to more than 1/2 X 2-1/2 inches.
OPTION 5. Three Plane Repair. Damage
to a three plane area will be repaired
in the same manner as described in
option 3, except the hole should not be
enlarged to more than 1/2 X 2-1/2 inches
and the rubber plug will be cut as shown
in Figure 12-5. This will allow the
plug to assume the contour of the tank
when pulled into place.
12-8