Radio failure inbound to Windhoek Eros
You are inbound VFR to Windhoek Eros from the north in a C172. You have been cleared to enter the control zone and to land on Runway 20. After you read back the clearance, the radio fails completely; the transponder still works. You are 12 nm from the field at 7,500 ft, in VMC, with 1 hour 40 minutes of fuel. Eros is a controlled aerodrome with a tower; the ATIS is not received. You have a mobile phone but no handheld radio. Another aircraft is ahead of you on the same route. You need to decide whether to continue, orbit, or divert to Hosea Kutako International. The tower has your callsign and position from the earlier clearance, and the weather is CAVOK.
1. State your immediate actions after the radio failure and justify continuing or not continuing.
Read the worked answer
Squawk 7600. Check the radio installation: volume, squelch, headset, frequency, circuit breaker and the second VHF radio. Listen on 121.5 and try to relay through the aircraft ahead. If a mobile phone is available and a passenger can use it, call the tower. Because a clearance to enter the control zone and land has already been received and acknowledged, continue VFR on the cleared route and at a safe altitude, and watch for light signals from the tower. Do not enter cloud or change to an IFR procedure. If no clearance had been received, the pilot should remain outside controlled airspace and land at a suitable uncontrolled aerodrome. With CAVOK and 1 hour 40 minutes of fuel, continuing to Eros is reasonable, but the pilot must be prepared to orbit or divert if light signals are not seen.
2. What light signals should you expect from the tower, and what does each mean?
Read the worked answer
For an aircraft in flight, a steady green light means cleared to land. A flashing green light means return for landing, to be followed by a steady green at the proper time. A steady red light means give way to other aircraft and continue circling. A flashing red light means the aerodrome is unsafe and you must not land. An alternating red and green light means danger and you should exercise extreme caution. On the ground after landing, a steady green light means cleared for take-off and a flashing green light means cleared to taxi; a steady red means stop. The pilot should acknowledge signals where possible and comply immediately, remembering that the tower may be separating other traffic around the radio-failure aircraft.
3. If the radio is restored on final approach, what should you transmit and what should you do next?
Read the worked answer
Transmit a concise position and intention report, for example: 'Eros Tower, Zulu-Sierra-ABC, radio failure, final runway 20, request landing instructions.' Then read back the clearance and follow it. If the radio is restored after landing, contact ground control, state that the radio failure has been resolved and request taxi instructions. Do not assume the clearance still applies if traffic has changed; the tower may issue a new landing or go-around instruction. The priority is to re-establish two-way communication, identify the aircraft and position clearly, and comply with the updated clearance.