TB 1--1520--238--20--129
(3) Upon completion of the next 50/125 hour special inspection, ULLS--A units will make the fol-
lowing changes to their inspection master files--
(a) AH--64D-- Delete inspection numbers A132 and A229. Modify inspection number A131
(APU clutch inspection and reference).
(b) AH--64A-- Delete inspection numbers A229 and A223. Modify inspection number A131
(APU clutch inspection and reference), and the next due date if applicable.
b. APU clutch 50 hour recurring inspection. This inspection will supersedes the current APU clutch 50
and 125 hour clutch inspections in the AH--64A TM and AH--64D IETM and will be performed every 50 flight
hours.
(1) Inspect APU mounts for cracks, dents, distortion, loose bolts and corrosion. None allowed.
NOTE
Particular attention must be given to the welded joints.
(a) Inspect the entire length of each weld line for crack and any other abnormalities (TM
1--1520--238--23, paragraph 15.1 and the IETM).
(b) Inspect all attachment lugs for cracks and looseness. None allowed.
(c) Inspect all attachment points for loose or missing hardware. All bushings must be in place
and hardware must be properly torqued.
(2) Remove anti--flail support and APU drive shaft IAW with the TM or IETM.
(3) Check APU power take off (PTO) clutch for external oil or grease leaks.
NOTE
It is normal for grease to appear within 15 to 25 hours of operation after installation of
a new clutch. If grease is noted after two consecutive 50 flight hour inspection following
the initial finding, remove and replace the PTO clutch.
(a) Inspect duplex vent and forward lip seal for grease. If present, remove grease and clean
PTO clutch exterior, record findings on DA Form 2408--13--1.
(b) Inspect duplex vent and forward lip seal for oil None allowed.
NOTE
Some wetness from the duplex vent is acceptable. Oil leaking from the APU at the du-
plex vent is not acceptable.
(c) Check APU PTO clutch for grease discharge from the covered port. None allowed.
NOTE
External grease leakage is most likely to be at the forward lip seal and duplex vent. Do
not confuse grease at the covered port with grease coming from the duplex vent.
Grease from the duplex vent will migrate to the covered port area. Grease may vent
through the duplex vent under certain conditions such as overfilling or operating under
high temperatures.
NOTE
Grease discharge from the covered port at the bottom of the PTO clutch housing is not
acceptable. This is an indication of internal leakage which will contaminate clutch sur-
faces. If grease discharge is noted at the covered port, the clutch assembly shall be
replaced. Wetness from oil seepage at the covered port is acceptable as long as the
oil leakage rate does not exceed one drop per minute from the covered port with the APU
running.
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