ROTARY-WING BLADE LIGHTNING STRIKE INSPECTION
Aircraft Mechanics Tool Kit, NSN 5180-00-323-4692
Magnifying Glass, 10X Minimum
Bond Test Unit
CH-47 Helicopter Repairer (2)
Battery Disconnected (Task 1-39)
Electrical Power Off
Hydraulic Power Off
Blade Tiedown Ropes Installed (Task 1-26)
Work Platform Open as Required (Task 2-2)
If helicopter is struck by lightning, inspect
rotary-wing blades before next flight. Inspect
blades as follows:
Visually inspect entire rotor blade upper and
lower surfaces for obvious extensive damage
which would prevent further flight.
Using a coin, tap around burned or discolored
areas for voids that exceed permissible limits
(Task 5-63.1). If a void is suspected, refer to
To prevent further damage, voids or
delamination open to the airstream (forward
edge) can be filled with adhesive or wrapped
with fabric tape (E395). If voids or cracks are
present on lightning jumper strip (1), the strip
can be removed (Task 5-81.3.1).
Visually inspect pitch housings (2) for burns
in the area of the lightning cable connections
(3). Use a magnifying glass of at least 10X
Within next 20 flight hours after lightning strike,
inspect rotary-wing blades as follows:
Visually inspect entire blade for
delamination(s), voids, and other defect(s),
which may have been caused by the strike.
Coin tap inspect the following areas for bond
voids (Task 5-63.1): If a void is suspected,
refer to TM 1-1520-253-23.
Entire area of cap nose (4).
Entire lightning strip (1), upper and lower
surfaces, from inboard end of nose
cap (4) at STA 77.00 to lightning cable
connection (3) at STA 33.80.
Entire trim tab (5).
Visually inspect trailing edge of nose cap
(4) in areas of visual damage for cracking,
pitting, etc. Use a magnifying glass of at least