TB 1-1520-237-20-151
NOTE
Depots that do not have the capability to inspect the subject assemblies in accordance with this
TB, contact the logistical point of contact. Do not issue until this TB has been complied with.
2. Task/lnspection Suspense Date. Within 10 hours/14 days from receipt of superseded message or
receipt of this TB, whichever is received first (if not previously complied with).
3. Reporting Compliance Suspense Date. Report compliance to Commander, ATCOM, ATTN:
AMSAT-C-XS no later than 3 February 1994 per paragraph 14a of this TB (if not previously complied with).
4.
Summary of the Problem.
a. During overhaul, some main rotor spindles have been found with localized debonding of the spindle
liner. To correct this problem a new bonding procedure has been developed which must be incorporated on
all previously produced spindle assemblies.
b. Sikorsky Aircraft has identified a potential problem with delamination of some Chicago Rawhide
elastomeric thrust bearings. This delamination can potentially allow metal to metal contact between the
spindle assembly and the bearing shims.
d. The purpose of this TB is to:
(1) Identify spindle assemblies which may require future removal/rework.
(2) Provide instructions/procedures to:
(a) At the next PMS-2 inspection, replace all Part Number (P/A) SB7002-046, P/N
(B40-80-9597), Serial Number (S/N) C325-00001 through S/N C325-02408 Chicago Rawhide thrust
bearings with P/N SB7002-048 (LB5-1034-1-3 Lord Corporation) or Chicago Rawhide P/N
(840-80-9601) S/N C325-02409 and subsequent thrust bearings.
(b) Issue new thrust bearings directly to each MACOM/installation for distribution at no cost
to the user/government.
(c) Eliminate the recurring 30 hour special inspection required of thrust bearings after above
suspect bearings are replaced.
5. End Items to be inspected. All H-60 Army aircraft
6.
Assembly Components to be Inspected
NOMENCLATURE
PART NUMBER
NATIONAL STOCK NUMBER
Main
Rotor
Spndl
Assy
70102-08200-041
NNSN
Main
Rotor
Spndl
Assy
70102-08200-042
Main
Rotor
Spndl
Assy
70102-08200-043
NNSN
Main
Rotor
Spndl
Assy
70102-08200-044
Main Rotor Spndl Assy
70102-08200-053
NNSN
Main Rotor Spndl Assy
70102-08200-054
Main Rotor Spndl
Assy
70070-10030-041
NNSN
w/ Tie Rod
Main Rotor Spndl
Assy
70070-10030-042
w/ Tie Rod
Main Rotor Spndl
Assy
70070-10030-044
1615-01-353-4884
w/ Tie Rod
Main Rotor Spndl
Assy
70070-10030-045
NNSN
w/ Tie Rod
2