Communication equipment and radio failure procedures
Communication equipment and radio failure procedures
This domain tests pre-flight radio checks, equipment knowledge, and the actions to take when two-way radio communication fails in controlled or uncontrolled airspace.
Core rules
- Before flight, check the radio, headset, microphone, antenna, circuit breakers and backup power. Confirm you can transmit and receive on the expected frequencies.
- In controlled airspace, a serviceable two-way radio is normally required. If radio fails, squawk 7600, continue in VMC if possible, and follow the published radio-failure procedure.
- Try to re-establish: check headset, volume, squelch, frequency and circuit breakers; try another radio or handheld; relay through another aircraft; listen for ATC on nearby frequencies.
- If you cannot re-establish in controlled airspace, remain VMC, leave controlled airspace if required, and land at the nearest suitable aerodrome. Telephone ATS afterwards.
- ATC may use light signals if radio is lost: steady green = cleared to land; flashing green = return for landing; steady red = give way or stop; flashing red = taxi clear of runway; alternating red/green = general warning.
Worked example
You are VFR in a Class D control zone and your radio fails. You squawk 7600, check the headset and circuit breaker, try the handheld, and transmit blind on the tower frequency: 'Christchurch Tower, ZK-ABC, radio failure, 5 miles south, landing.' You remain VMC, join the circuit, watch for light signals, land, and phone the tower. You do not continue into cloud or enter Class C airspace without a clearance.
Traps
- Squawking 7700 for a radio failure; 7600 is the correct code.
- Continuing VFR into IMC after radio failure.
- Leaving the radio on the wrong frequency and missing ATC calls.
- Forgetting to try a handheld or relay.
Communication equipment and radio failure procedures
A backup radio is only useful if you have rehearsed how to select the emergency frequency and transmit blind.