FAA Aircraft Dispatcher (ADX)Navigation and ATCEasy
During a Part 121 flight, a dispatcher observes that the flight crew has lost two-way radio communication. Which transponder code should the flight crew squawk to indicate a radio communications failure?
- A7500
- B7700
- C7600
- D1200
Show answer & explanationAnswer & explanation
Correct answer: C. 7600
Code 7600 is the standard transponder code used to indicate loss of two-way radio communications. 7500 indicates hijacking, 7700 indicates a general emergency, and 1200 is the VFR code.
Why the other options are wrong
- A. 7500 signals unlawful interference/hijacking, not radio failure.
- B. 7700 is the general emergency code, used for a broader range of emergencies.
- D. 1200 is the standard VFR code, not related to communications failure.
Transponder Emergency Codes
Specific four-digit transponder codes alert ATC to specific situations without voice communication.
- 7500 = hijacking
- 7600 = lost communications
- 7700 = general emergency
Memory trick: 7-5-6-7: Hijack, Lost comm, Emergency (climbing severity)