- Effective
- October 24, 1968
- Models
- S-61A, S-61L, S-61N
- Registered aircraft
- 52 matched by model
- Product
- Aircraft · Rotorcraft
- Amendment
- 39-671
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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|---|---|---|---|
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On this page
The airworthiness directive
68-21-06 SIKORSKY: Amendment 39-671. Applies to S-61A, S-61L, S-61N Type Helicopters.
(a) Within the next ten hours time in service after the effective date of this Airworthiness Directive unless already accomplished, deactivate the automatic flight control system (AFCS) by disconnecting the power sources to the AFCS system and the channel monitor panel as follows:
(1) Pull circuit breakers for electric power to the channel monitor panel and the AFCS system and safety the circuitbreaker buttons in the tripped position.
(2) Disconnect electrical connectors at the aux. servos and secure to wire bundle. Electrically ground all three pins on each plug on the aux. servos.
(b) For Models S-61L and S-61N, the AFCS may be reactivated when Sikorsky Service Bulletin No. 61B55-10A, dated October 4, 1968, or later FAA approved revision, or equivalent alteration approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
(c) For Model S-61A, the AFCS maybe reactivated when an alteration approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region is incorporated.
This amendment is effective October 24, 1968, and supersedes the telegram dated September 17, 1968 on this subject.
Affected TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 52
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 | 1 |
| 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 |
8 with no year recorded