SH125WE
Installation of AiResearch TSE-331-3U-303N engine and related changes. (Limited to serial number 55607). Held by Aviation Specialties, INC. Last revised June 25, 1971. System: engine.
What it applies to
- Kind of product
- Aircraft
- Design holder
- Sikorsky Aircraft Corporation
- Models
- S-55B
- Type certificate
- 1H4
- On this site
- Sikorsky S-55 15 registered
- The FAA's record
- On the FAA's site
What an approved modification is
A supplemental type certificate is the FAA's approval of a change to a certified design: a new engine or propeller, avionics, an autopilot, floats, a parachute, a larger fuel tank, an ice-protection kit. The company holding it may sell the kit and the paperwork to owners of the listed models; the modification then becomes part of that aircraft's record. The FAA's list says what was approved and for which models, not how many aircraft carry it.
Source: FAA supplemental type certificates (Dynamic Regulatory System). Register counts from the FAA register of October 20, 2026.