TB 1-1520-237-20-181
(2) Wholesale Stock. Upon receipt of this TB, depot commanders shall ensure inspection of all items listed in
paragraph 6. All items listed in paragraph 6. below shall be placed in conditions code " " and retagged with a
D
Test/Modification Tag/Label Material (blue color) DD Form 157611576-1. The authority block must reference inspections
required per this TB.
2. Task/Inspection Suspense Date. Within 100 flight hours/180 days whichever comes first.
3. Reporting Compliance Suspense Date. No later than 29 October 1996 per paragraph 14.a. of this TB.
4. Summary of the Problem.
a. During manufacturing of some main rotor hub assemblies, the proper edge break was not applied to the inside
edge of one of the damper bracket attachment holes. Stress risers can result from this condition, which increases the
opportunity for cracks to develop.
b. For manpower/downtime and funding impacts, see paragraph 12.
c. The purpose of this TB is to:
(1) Inspect all main rotor hub assemblies for proper edge break.
(2) NDI inspect and edge break all assemblies found deficient.
(3) Perform a NDI inspection on all main rotor hubs for cracks during the 500 hour phase inspection.
5. End Items to be Inspected. All H-60 aircraft. Serial Numbers 95-26645, 95-26650 through 95-26655 and 95-26660
and subsequent will be inspected and corrected for proper edge break by the contractor during production. However,
these hubs will require the NDI inspection at the 500 hour phase IAW paragraph 9.d.
6. Assembly Components to be Inspected.
NOMENCLATURE
PART NUMBER
NATIONAL STOCK NUMBER
Main Rotor Hub Assembly
70103-08112-041
Main Rotor Hub Assembly
70103-08112-045
7. Parts to be Inspected. N/A.
8. Inspection Procedures. A visual inspection of all main rotor hub assemblies will be performed by a Sikorsky Aircraft
representative. The Sikorsky Aircraft representative will be scheduled in accordance with paragraph 9.a. The Sikorsky
representative will visually inspect all hub assemblies at the damper bracket 11 O'Clock bolt hole for proper edge break If
the edge break is found deficient on Sikorsky manufactured assemblies, a Sikorsky team will perform the required rework
and NDI inspections as described in paragraph 9.b. If the assembly was manufactured by Purdy Manufacturing, a Purdy
team will perform the required rework as described in paragraph 9.b. All hub assemblies that remain in service will
require a minimum of one NDI inspection as described in paragraph 9.d.
9. Correction Procedures.
a. One-Time Inspection for Proper Edge Break Scheduling of the one-time inspection for edge break will be
controlled by the logistical point of contact (POC). Units will be notified of the date when the inspection is scheduled for
their aircraft. No disassembly is required for the inspection. The inspection will be conducted by Sikorsky
representatives.
b. If a hub assembly is found deficient, a Sikorsky team or Purdy team will perform the necessary rework
including:
(1) Initial NDI inspection for cracks.
(2) Break sharp edge around 11 O'Clock hole.
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