TB1--1520--238--20--104
Inspection Procedures.
a. For all hanger bearing assemblies listed in para 7.
(1) AMCOM Logistic Assistance Representatives (LAR) will physically inspect aircraft and sup-
ply facilities to determine location of suspect hanger bearing assemblies listed in para 7.
(2) Upon indentification of suspect hanger bearing assemblies. Depot teams (CCAD--CONUS/
OLR Europe) will verify the proper nutation torque.
b. Upon installation of any hanger bearing assemblies and at each 250 Hour Phase Maintenance In-
spection-- AVUM/AVIM personnel shall verify nut torque and check nutation IAW this para using locally fabri-
cated AH--64 Hanger Bearing Nutation/Torque Reactor Tool (tool number AH64HBTN), Figure 1.
(1) Perform nutation check as follows:
(a) Remove drive shafts and tail rotor couplings per TM 1--1520--238--23 or Longbow IETM.
(b) Install AH--64 Nutation/Torque Reactor Tool. Ensure that the small flange is pointed in-
ward toward the hanger bearing, see Figure 2. Attaching the tool with the flange pointed away from the
bearing will add to the torque arm and result in an incorrect nutation check.
NOTE
Nutation is the angular movement of the bearing off of its center axis. It is not rotation.
(c) Attach a torque wrench, to the small flange with the 3/8 inch attachment hole.
(d) Check the breakaway nutation torque in three planes (12, 4, and 8 o'clock positions) from
the centered starting position. Ensure that the breakaway nutation torque is between 10 and 300 INCH
POUNDS in all three planes.
(2) Perform the nut torque check as follows:
(a) Inspect NAS1022C14 nut for broken or missing torque stripe. If torque stripe is intact,
inspection is complete.
(b) If torque stripe is missing or broken, verify 700--800 inch pound torque by turning nut in
clockwise direction. Use the AH--64 Nutation/Torque Reactor Tool and 1/2 inch drive breaker bar to re-
strain hanger bearing flange.
(c) If nut turns before reaching 700 INCH POUNDS replace nut. Torque new nut to 700--800
INCH POUNDS above running torque. Apply torque stripe.
9. Correction Procedures.If any forward or aft hanger bearing assembly break--away nutation torque is-
less than 10 INCH POUNDS replace hanger bearing assembly. If any forward or aft hanger bearing assembly
break--away nutation torque is over 300 INCH POUNDS, disassemble and clean the bearing as follows:
a. Record the torque value on the DA Form 2408--5--1, regardless of whether it passes or fails. Identify
this measurement as "initial nutation torque". If disassembly, cleaning, and reassembly produces an accept-
able nutation torque value, record that value also. Identify this measurement as "installation nutation torque".
b. The following procedures shall be used to perform the aft hanger bearing cleaning. See Figure 3
for item call out numbers.
(1) Secure hanger bearing to work bench. Match mark flanges, bearing retainer, and mount.
(2) Install the nutation tool onto the hanger bearing.
(3) Remove self locking nut (1), pilot spacer (2), input flange (4), and bearing spacer (5) from the
hanger bearing subassembly, use a 1/2 inch breaker bar attached to the nutation tool as a torque reactor.
(4) Remove six bolts (7), six self--locking nuts (8), and 12 flat washers (9). Discard self--locking
nuts.
(5) Tag and remove spacer shims (11), output flange (3), two bearing retainers (12), and ball
bearing (13) from bearing hanger (10). Out put flange (3), one retainer (12), and ball bearing (13) will come
off as an assembly.
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