- Effective
- December 23, 1975
- Models
- S-61A, S-61D, S-61E, S-61L, S-61N, S-61NM, S-61R, S-61V
- Registered aircraft
- 54 matched by model
- Product
- Aircraft · Rotorcraft
- Amendment
- 39-2450
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
68-19-07 SIKORSKY: Amendment 39-657 as amended by Amendment 39-2450. Applies to S-61 Series helicopters.
Compliance required as indicated.
To preclude the possibility of failure of the main rotor blade spindle, accomplish the following:
(a) Before further flight, remove main rotor blade spindles P/Ns S6110-23325-1, S6110-23325-2, and S6112-23025-1 that either have been "salvaged" in accordance with procedures set forth in paragraph entitled "Salvage of Spindle" contained in Sikorsky Aircraft Overhaul Manual for the pertinent helicopter model, or have accumulated 3000 or more hours' time in service on the effective date of this AD, and replace with blade spindles of the same part number that have not been "salvaged" and that have less than 3000 hours' time in service.
(b) Replace main rotor blade spindles P/Ns S6110-23325-1, S6110-23325-2, and S6112-23025-1, that have not been "salvaged" and have less than 3000 hours' time in service on the effective date of thisAD, before the accumulation of 3000 hours' time in service with main rotor blades spindles of the same part number that have not been "salvaged" and have less than 3000 hours' time in service.
(c) Before further flight, remove from service main rotor blade spindles P/N's S6110-23325-1, S6110-2325-2, and S6112-23025-1, serial numbers AX51, AX54, F2148, F2444, F2485, F2207, F1406, F1416, F1415, F1399, B-35, and F2451.
Amendment 39-657 was effective September 27, 1968.
This amendment 39-2450 becomes effective December 23, 1975.
Affected TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 54
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1960 | 1 |
|---|---|
| 1961 | 2 |
| 1962 | 1 |
| 1963 | 4 |
| 1964 | 2 |
| 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