- Effective
- December 12, 1974
- Models
- S-64A, S-64E
- Data sheet
- TCDSH1EA
- Registered aircraft
- 16 matched by model
- Product
- Aircraft · Rotorcraft
- Amendment
- 39-2033
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 | 21 KB | 41782a58…6c795d7 | FAA DRS (API key needed) |
On this page
The airworthiness directive
74-16-05 SIKORSKY AIRCRAFT: Amendment 39-1910 is amended by Amendment 39-2033. Applies to S-64A, S-64E, and S-56 helicopters certificated in all categories.
Compliance required as indicated.
To prevent fatigue failures of the main rotor head spindle lock nut, accomplish the following:
(a) Before the accumulation of 750 hours time in service on a main rotor head spindle lock nut, P/N S1510-23031-0, or within the next 25 hours time in service after the effective date of this AD, whichever occurs later, replace the affected lock nut with a serviceable part of the same part number and thereafter repeat replacement at intervals not to exceed 750 hours time in service.
(b) Before the accumulation of 10,500 hours time in service on a main rotor head spindle lock nut, P/N S1510-23031-1, or within the next 25 hours time in service after the effective date of this AD, whichever occurs later, replace the affected lock nut with a serviceable part of the same part number and thereafter repeat replacement at intervals not to exceed 10,500 hours time in service.
Amendment 39-1910 became effective August 15, 1974.
This amendment 39-2033 becomes effective December 12, 1974.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 16
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1962 | 1 |
|---|---|
| 1967 | 5 |
| 1968 | 7 |
| 1975 | 2 |
| 1997 | 1 |