Supplementary Type Certificate
 

For example, the FAA hold a couple of STCs for the V2500 T/R & exhaust system.

What does this actually mean???

Thanks!!!!!

Supplemental Type Certificates
 

A supplemental type certificate (STC) is a type certificate (TC) issued when an applicant has received FAA approval to modify an aircraft from its original design. The STC, which incorporates by reference the related TC, approves not only the modification but also how that modification affects the original design.