PS Magazine - TB 43-PS-560
PS, The Preventative Maintenance Monthly
ISSUE 560
JULY 1999
Brace Up the Bracket
T
he Apache auxiliary power unit cover’s upper bracket assembly, NSN 1560-
01-186-4078, can come unglued from the firewall. Once it’s loose, it can
cause FOD.
So, make sure the bracket stays put. After you glue it back in place, put
a monel rivet, NSN 5320-01-042-2896, in each side of the bracket with a
0.032-in 2024 T3 aluminum backing plate on the other side of the firewall. The
rivets should be centered on the bracket
3
/
8
inch from each edge. That will keep
it secure.
A PS 529 (Dec 96) article on this fix
showed a picture of the lower bracket
on the engine mount. That was wrong.
Never put any rivets in this bracket.
That will weaken and crack the engine
mount support and you’ll have to re-
place it.
Check
fluid level
indicator
before
and after
firing
AH-64 . . .
AVIM’s job is to tear down the re-
coil adapters during each phase
maintenance to check for corrosion im-
proper assembly, and binding parts.
The procedure’s in Para 4-8-2 in TM
9-1090-208-23-1-2.
Remove and install the adapters the
way it shows in Para 4-7-6.
Inspect the adapters for leakage and
proper fluid level when you do the
BEFORE and AFTER FIRING checks
in Para 4-5-1 and Para 4-5-2.
Your job is making sure high-
pressure water is kept away from the
recoil adapters.
Then, use only damping fluid, NSN
9150-01-056-7346, to fill the adapters.
The procedure’s in Para 4-7-7 of TM
9-1090-208-23-1-1.
•
Internal check valves not working
because they had been reassembled
using too much sealing compound
or the wrong kind of sealing
compound
•
Corrosion resulting from water
forced into the adapters by high-
pressure washing
•
Bent indicator rods caused by
improper removal of the adapters
To stop recoil adapter problems, you
repairmen will need to work with your
AVIM.
h
o
ld it
!
don't you know
what
high pressure
water
can do to
my gun's
recoil
adapters
?
hold it
!
PS 560
37
JUL 99
PS 560
36
Use correct damping fluid
Put
rivets
here.
..
...not here
f the recoil adapters for the AH-
64’s 30mm guns stop recoiling, all sorts
of damage can result. One aviation
unit’s searchlights stopped working be-
cause gun vibration broke the lights’
mounting screws and electrical relays.
Investigation of that unit’s recoil
adapters showed the following
problems:
•
Wrong damping fluid, which
caused poor recoil damping
•
Loose internal adapter parts caused
by improper reassembly
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