REPAIR TITANIUM NOSE CAP CRACKS (AVIM)
The preparation and bonding of the
titanium nose cap doubler is a critical
repair. It must be performed exactly
as described. If possible, surface
preparation and bonding shall be done
in a controlled environment to avoid
contamination and to obtain proper
adhesive cure. Failure to follow these
instructions can result in unbending
of the doubler and subsequent injury
Do not repair titanium nose cap cracks
outboard of sta. 303.
There is no limit to the number
of repairs that can be done on a
nose cap. The minimum distance
between repairs, measured between
centerlines, shall be 12 inches. If
cracks occur closer than 12 inches,
blade is not reparable at this level.
Position blade (1) in adapter (T164) (2) with nose
cap (3) up.
Tape polyvinyl sheets (E284) (4) over top and
bottom of blade (5) aft of crack (6). Use masking
tape (E388) (7).
Remove only black lacquer or
polyurethane paint finish. Green
primer must remain to provide
satisfactory bond. If bare titanium is
exposed, DeSoto primer (E291.1)
must be applied.
Do not use chlorinated solvents on
titanium nose cap or doubler. These
solvents cause material failure.
Determine the finish system used on the rotor
blade (TM 55-1500-344-23).
Remove black lacquer or polyurethane paint
from strip 4-1/2 inches wide on each side of
crack (6) on both sides of cap (3). Use abrasive
paper (E9). Use very light pressure. Sand only
as required to remove lacquer.