- Models
- HRS-1/CH-19, HRS-3/H-19B, S-55, S-55B, S-55C
- Registered aircraft
- 17 matched by model
- Product
- Aircraft · Rotorcraft
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 | e9cea397…57b07ba | FAA DRS (API key needed) |
On this page
The airworthiness directive
54-13-01 SIKORSKY: Applies to All Model S-55 Helicopters.
Compliance required as indicated.
1. The twelve (12) AN 73A bolts which clamp the S510170 retainer to the bottom of S10-10-4302 rotating star, and the eight (8) AN 73A bolts which clamp the S510156 retainer to the top of the S10-10-4302 rotating star should be replaced. The 20 new bolts should be torqued to 25-35 inch-pounds. These replacements are to be accomplished every 60 hours until the AN 74A bolts called for in item 2. are incorporated.
2. At the next major overhaul period of the star assembly S10-10-4300, replace the twenty (20) AN 73A bolts covered in 1 with 1/4-inch diameter AN 74A bolts. The AN 74A bolts should be relocated between the existing holes. When the AN 74A bolts have been incorporated, the replacements of 1 are no longer required.
3. At the next major overhaul period of the star assembly S10-10-4300, replace the twelve (12) AN 509-10R-35 screws which secure the clamp the S12-10-4015 liner and the Y96PW1-DB bearings to the S12-10-4013 stationary star. The screws should be torqued to 35- 40 inch-pounds.
(Sikorsky Service Information Circular No. 1410-222 dated March 4, 1952, through Revision D dated April 15, 1954, covers this same subject.)
Affected TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 17
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1952 | 1 |
|---|---|
| 1953 | 1 |
| 1954 | 3 |
| 1955 | 3 |
| 1956 | 2 |
| 1957 | 2 |
| 1959 | 1 |
| 1996 | 1 |
| 1997 | 1 |
2 with no year recorded