FAA Commercial Pilot Airplane (CAX)RegulationsEasy
A mechanic installs and calibrates a new ATC transponder in a commercial operator's airplane used for IFR flights. According to 14 CFR 91.413, this transponder must be tested and inspected within the preceding how many calendar months, and in accordance with which standard?
- A24 calendar months, Part 43 Appendix F
- B24 calendar months, Part 43 Appendix E
- C12 calendar months, Part 43 Appendix E
- D12 calendar months, Part 43 Appendix F
Show answer & explanationAnswer & explanation
Correct answer: A. 24 calendar months, Part 43 Appendix F
14 CFR 91.413 requires ATC transponders to be tested and inspected within the preceding 24 calendar months in accordance with the procedures in Part 43, Appendix F. This mirrors the altimeter system's 24-month cycle but uses a different appendix.
Why the other options are wrong
- B. Appendix E is for the altimeter/static system, not the transponder
- C. 12 months is incorrect, and Appendix E applies to altimeter/static systems, not transponders
- D. 12 months does not apply; the correct interval is 24 months
Transponder Inspection (91.413)
ATC transponders must be tested and inspected within the preceding 24 calendar months per Part 43 Appendix F.
- 24 calendar month interval
- Uses Part 43 Appendix F procedures
- Distinct from the altimeter's Appendix E test
Memory trick: 'F is for Frequency-finder' (transponder) — remember F for the transponder appendix.