Type certificate E-291
Held today by Pratt & Whitney Division. It covers 6 models; about 1 aircraft on the U.S. register are built to it. Last revised September 15, 1967 (revision 12). 9 FAA orders name its designs.
Models under this certificate 6
JT4A-11, JT4A-3, JT4A-9, JT4A-10, JT4A-5, JT4A-12
Engine series
The data sheet on the FAA's site: the approved engines and propellers, weights, speeds and limits for each model.
FAA orders on these designs 9 · newest first
1976-05-2076-01-08 · Tenth Stage Compressor Blade · engine
1971-05-1971-06-03 · Twelfth Stage Compressor Rotor Disc · engine
1971-05-0471-02-02 · Twelfth Stage Compressor Rotor Disc · engine
1968-06-1268-12-03 · High Compressor Rotor Blade Failure · engine
1967-01-0567-01-03 · Fuel Manifold Assembly · engine
1964-05-2664-11-04 · Front Compressor Rotor Assemblies · engine
1964-02-2764-05-05 · Throttle Valve Assemblies · engine
56-06-02 · Cylinder Flange Attaching Stud · engine
Source: FAA type certificate data sheets (Dynamic Regulatory System); register counts from the FAA register of October 7, 2026. Connections as data: /graph/certificate/E-291.json.