Communication Failure Procedures
Communication failure procedures
This domain tests the drills you follow when the transmitter or receiver fails, and the parallel actions taken by ATS.
First actions
Squawk 7600. Try every means available: another radio, 121.5, a relay through another aircraft, a company frequency, or a telephone to the unit. If only the receiver has failed, keep transmitting in the blind, prefixing reports 'TRANSMITTING BLIND DUE TO RECEIVER FAILURE'. If only the transmitter has failed, keep listening and acknowledge instructions by whatever means remain.
If the failure persists in IMC
Maintain the last assigned speed and level for seven minutes, then adjust to the level in the flight plan; if there is no flight plan, climb to the minimum safe altitude. Continue to destination or the nearest suitable aerodrome and begin descent at the expected approach time.
ATS side
The controller will try 121.5, use radar or ADS-B to keep you separated, and clear the surrounding traffic. Watch for light signals: steady green means cleared to land in flight, or cleared for take-off on the ground; flashing green means return for landing, or cleared to taxi; steady red means give way and continue circling, or stop; flashing red means aerodrome unsafe, do not land, or taxi clear of the landing area; flashing white means return to the starting point on the aerodrome.
Worked example
Both radios fail in IMC on an IFR clearance at FL150, with a flight-planned level of FL180. Select 7600, transmit blind, hold FL150 for seven minutes, then climb to FL180, continue to destination and descend at the EAT. The seven-minute hold gives the controller time to create space before you change level.
Traps
Selecting 7700; descending immediately; omitting 121.5 from your attempts; ignoring the seven-minute rule; confusing flashing red with steady red.