Type certificate TC 173
Held today by Textron Lycoming Avco Corporation, earlier by Avco Corporation, Lycoming Division. It covers 1 model; about 225 aircraft on the U.S. register are built to it. Last revised November 2, 1950 (revision 0). 5 FAA orders name its designs, and 2 approved modifications build on it.
Models under this certificate 1
R-680-D6
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 5 · newest first
2012-03-272012-03-07 · Carburetor · engine
2004-06-252004-10-14 · Crankshaft gear · engine
1996-01-2495-26-02 · Aviation Gasoline · engine
1991-05-2890-04-06 R1 · Propeller Governor External Oil Line · engine
1969-01-1666-06-03 · Connecting Rod Assemblies · engine
Approved modifications 2 · companies holding the most
Source: FAA type certificate data sheets (Dynamic Regulatory System); register counts from the FAA register of October 5, 2026. Connections as data: /graph/certificate/TC 173.json.