When IFF communications are lost, which code is indicated?

When IFF communications are lost, which code is indicated?

• A. 7600
• B. 7500
• C. 7601
• D. 7700

Answer: (A)

Think in terms of how ATC learns you’re not able to talk: the transponder has a specific code reserved to indicate radio failure. When that code is chosen, it immediately tells air traffic control that you cannot receive or transmit by voice, so they switch to non-voice procedures and plan to manage you with the last assigned routing and altitude or the expected route. This is the standard signal for loss of communication, making it the best answer for the question. The other widely used codes indicate different situations—one signals hijack, another signals a general emergency—so they would lead to different ATC responses. The option that isn’t part of standard signaling wouldn’t be used in routine operations.

Think in terms of how ATC learns you’re not able to talk: the transponder has a specific code reserved to indicate radio failure. When that code is chosen, it immediately tells air traffic control that you cannot receive or transmit by voice, so they switch to non-voice procedures and plan to manage you with the last assigned routing and altitude or the expected route. This is the standard signal for loss of communication, making it the best answer for the question. The other widely used codes indicate different situations—one signals hijack, another signals a general emergency—so they would lead to different ATC responses. The option that isn’t part of standard signaling wouldn’t be used in routine operations.