What squawk code must be used during a communication failure?

What squawk code must be used during a communication failure?

• A. 7600
• B. 7700
• C. 7500
• D. 0000

Answer: (A)

When radio communications are lost, the aircraft must signal that condition to ATC by using the transponder code 7600. This specific code immediately tells controllers that you have a communications failure, so they switch to loss‑of‑communications procedures and provide appropriate guidance and separation. The other codes indicate different situations: 7700 is for a general emergency, which would trigger urgent responses from ATC; 7500 indicates a hijack; and 0000 is not a standard code used to denote radio failure. Therefore, 7600 is the correct and designated code for a communication failure.

When radio communications are lost, the aircraft must signal that condition to ATC by using the transponder code 7600. This specific code immediately tells controllers that you have a communications failure, so they switch to loss‑of‑communications procedures and provide appropriate guidance and separation.

The other codes indicate different situations: 7700 is for a general emergency, which would trigger urgent responses from ATC; 7500 indicates a hijack; and 0000 is not a standard code used to denote radio failure. Therefore, 7600 is the correct and designated code for a communication failure.