- Effective
- October 7, 1971
- 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
- 39-1303
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.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| FAA DRS HTML | 20 KB | 49fa3208…9d16cc8 | FAA DRS (API key needed) |
On this page
The airworthiness directive
71-21-03 SIKORSKY: Amdt. 39-1303. Applies to all S-61 Type Helicopters certified in all categories.
Compliance required as indicated.
To prevent a hardover in the auxiliary servo system, as the result of fracture of the servo valve input linkage, accomplish the following:
a. Within the next 50 hours' time in service after the effective date of this AD, unless already accomplished, install a secondary link in the servo valve input linkage in accordance with Section 2, paragraphs A., B., C., and G., of Sikorsky Service Bulletin No. 61B65-6A, dated 1 July 1971, or later approved revisions or an equivalent installation, both approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.
b. Install secondary links per paragraph (a) on all spare units, prior to installation on the aircraft.
This amendment is effective October 7, 1971.
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