Subchapter 9.1 – Communication Failure Under IFR

Receiver Failure: Your radio has lost the receive function. You cannot hear ATC, ATIS, or other stations. ATC can still hear your transmissions.
Transmitter Failure: Your radio cannot transmit, but you can still receive. You hear ATC but cannot respond.
Complete Failure: Neither transmitter nor receiver functions. You are silent and deaf.
The procedures differ for each, but all begin with the same action: squawk 7600 on the transponder. This is the emergency code specifically assigned to radio failure. Within seconds, ATC will see a radar blip with code 7600 and immediately know they have a radio-failure aircraft. Even though you cannot communicate by voice, your transponder keeps ATC informed of your position and altitude.