TB 1-1520-237-20-182
3. Reporting Compliance Suspense Date. No later than 3 October 1996 per paragraph 14a. of this TB.
4. Summary of the Problem.
a. During a recent 500 hour phase maintenance inspection, a spindle shank was found to be circumferentially
cracked in the area of the thread root and spline. The preliminary failure investigation results have led to the belief that a
contributing factor to the premature failure of the spindle shank was excessive wear of the elastomeric teflon sleeve
bearing. This caused an increased gap between the spindle sleeve bearing and elastomeric teflon sleeve bearing which
results in greatly increased loads carried in the spindle thread area. As a result of this finding, all aircraft spindle
elastomeric bearings shall require replacement of the teflon sleeve bearing with a new (ZERO TIME) sleeve bearing at
the next 500 hour phase maintenance inspection (PMS-2) and each subsequent PMS-2.
b. For manpower/downtime and funding impacts see paragraph 12.
c. The purpose of this TB is twofold, (1) establish the requirements for replacement of the teflon sleeve bearing in
the spherical elastomeric bearing assembly at every 500 hour PMS-2 inspection, and (2) for aircraft currently undergoing
PMS-2 inspection or depot maintenance complete the inspection listed in 9a and as a one time requirement to collect
statistical data.
5. End Items to be Inspected. All H-60 series helicopters, spindle assemblies and spindle elastomeric bearings.
6. Assembly Components to be Inspected. N/A.
7. Parts to be Replaced.
NOMENCLATURE
PART NUMBER
NATIONAL STOCK NUMBER
Bearing, Sleeve
P/N SB5203-202
3120-01-083-3265
8. Inspection Procedures. Annotate the aircraft logbook to indicate that at every 500 hour phase maintenance
inspection (PMS-2) that the paragraph 9b correction procedures of this TB are required.
9. Correction Procedures.
a. All aircraft currently undergoing PMS-2 inspection or in Depot Maintenance will require the measurement
procedure "Inspect Elastomeric Bearing and Spindle Sleeve Bearing IAW TM 1-1520-237-23-3, paragraph 5.4.1.8.
Measure the currently installed elastomeric bearings teflon sleeve bearing inside diameter and the mating spindles
sleeve bearing outside diameter. The results of this measurement shall be recorded on the graph provided with the
procedure. Write the following on each graph: (1) the spindle assembly part number, serial number, time since new
(TSN), time since installed (TSI), aircraft tail number, and aircraft hours, (2) the elastomeric bearing part number, serial
number, TSN and TSI. Send a copy of each graph with the recorded diameter measurement results from each spindle
assembly and related information to: Commander, U.S. Army ATCOM, ATTN: AMSAT-R-ECU, 4300 Goodfellow Blvd,
St. Louis, MO 63120-1798, or fax to the technical point of contact at commercial (314) 263-1622, autovon 693-1622.
This submittal to ECU will complete the one-time data requirements of the TB.
b. Replace the sleeve bearing in all elastomeric bearing assemblies IAWTM 1-1520-237-23-3, paragraph
procedures, "Elastomeric Bearing Repair (AVIM)." This action will become a standard requirement of the PMS-2
inspection.
10. Supply/Parts and Disposition.
a. Parts Required. Bearing, Sleeve; P/N SB5203-202, NSN 3120-01-083-3265
b. Requisitioning Instructions. Requisition replacement parts through normal supply channels using normal supply
procedures. All requisitions shall use project code "XCG" per this TB.
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