TM 1-1520-238-23
1-402.12
Change 10
1.137.
SPECIAL INSPECTION CHECKLIST – continued
Helicopter Serial No.:
Date:
Area
No.
REQUIREMENT
EVERY
Item
Status
Special
Inspection
No.
5
43C
125 FLIGHT HOURS
INSPECTION OF AUXILIARY POWER UNIT POWER TAKE-OFF CLUTCH (P/N
3886000-5) AND MOUNTING STRUTS.
a. Inspect PTO clutch (P/N 3886000-5).
(1) Remove anti-flail support and APU drive shaft (para 6.16).
NOTE
External grease leakage is most likely to be at the forward lip seal and
duplex vent and will usually appear at the vent within the first 15 hours of
operation of a new clutch. 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, under these conditions, wipe grease away from the hous-
ing and perform APU MOC.
(2) Check APU PTO clutch for external oil or grease leaks.
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 surfaces. 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.
(3) Check APU PTO clutch for grease discharge from the covered port.
None allowed.
NOTE
Heat discoloration is usually confined to the duplex bearing housing area.
(4) Check APU PTO clutch for heat discoloration. None allowed.
(5) Check APU PTO clutch for cracks.
(a) If cracks are suspected, perform nondestructive inspection
(TM 1-1520-264-23).
(6) Check APU PTO clutch for corrosion. None allowed.
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