ith Collins TTR-920, Collins TTR-921 or Collins TTR-4000 Change 7.0 TCAS II Receiver Transmitter and optional TPR-901 in Part 25 Aircraft Dear Mr. Kremsreiter: Enclosed is a compact disk with one copy each of the following FAA approved STC data: 1. STC ST00881WI-D Certificate, dated December 1, 2000. 2.