48-18-02: Bevel Drive Gear Splines
FAA order 48-18-02 is an airworthiness directive. The FAA's subject line: Bevel Drive Gear Splines. System: other and general.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Sikorsky Aircraft Corporation
- Models
- S-51
Dates and paperwork
- Docket
- Unknown
- Status
- Current
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (569 characters)
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".
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 6, 2026. Connections as data: /graph/directive/48-18-02.json · aircraft systems.