- Model
- S-51
- Data sheet
- TCDSH-2
- 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 | 19 KB | dae67420…cf7a9eb | FAA DRS (API key needed) |
On this page
The airworthiness directive
48-18-02 SIKORSKY: Applies to Model S-51 Series Helicopters Serial Numbers SS-51- 01 Through SS-5157.
Compliance required at first main gearbox overhaul but in any event not later than the next 400 hours of operation.
To prevent cracks caused by stress concentration at the corners of the internal splines on the bevel drive gear (Sikorsky P/N S-535360), a 1/32-inch radius relief should be formed at the lower end of each spline. The procedure for accomplishing this modification is given in Sikorsky Aircraft Information Circular No. 40 and No. 40 Revision "A".
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.