- Effective
- February 17, 1976
- Models
- S-61L, S-61N, S-61NM, S-61R
- Data sheet
- TCDS1H15
- Registered aircraft
- 48 matched by model
- Product
- Aircraft · Rotorcraft
- Amendment
- 39-2507
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
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On this page
The airworthiness directive
76-03-02 SIKORSKY AIRCRAFT: Amendment 39-2507. Applies to S-61L, S-61N, S- 61NM, and S-61R helicopters certified in all categories including Military CH-3C, HH-3C, CH- 3E, and HH-3E helicopters using NAS 577-10 or NAS 577-10A barrel nuts for attaching the transmission main gearbox to the fuselage structure.
Compliance required as indicated.
To prevent fractures in the attaching nuts accomplish the following:
Remove the NAS 577-10 or NAS 577-10A barrel nuts and replace with RMLH 2577-108 barrel nuts within the next 30 days after the effective date of this AD, unless already accomplished. (NOTE: Sikorsky Service Bulletin No. 61B35-36B covers this subject.)
This supersedes Amendment 39-2202 (40 FR 24355), AD 75-12-13.
This amendment becomes effective February 17, 1976.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 48
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1962 | 1 |
|---|---|
| 1963 | 2 |
| 1964 | 1 |
| 1966 | 2 |
| 1968 | 3 |
| 1969 | 2 |
| 1970 | 1 |
| 1971 | 2 |
| 1972 | 1 |
| 1973 | 1 |
| 1974 | 4 |
| 1975 | 2 |
| 1976 | 2 |
| 1977 | 6 |
| 1978 | 3 |
| 1979 | 1 |
| 1980 | 4 |
| 1985 | 1 |
9 with no year recorded