An official website of the United States government
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
The minimum performance standards that gas turbine auxiliary power units (APU) must meet are specified in Technical Standard Order (TSO) C77b, dated December 20, 2000. Part 21, Subpart O, provides generic TSO approval procedures.