VFR radio failure after departure from SSR
You are pilot-in-command of a Cessna 172 on a VFR flight from Sir Seewoosagur Ramgoolam International Airport (FIMP) to a private airstrip 45 NM south-east. Before departure, ATC clears you: leave the control zone via the Golf departure, climb 2,500 ft, squawk 7042, contact Approach 121.10. The weather is VFR: surface wind 120/10 kt, visibility 15 km, SCT 3,000 ft, BKN 5,000 ft, temperature 29°C, QNH 1012. Fuel endurance is 3 h 00 min. Eight minutes after take-off, while still 4 NM inside the controlled airspace boundary, the VHF radio fails completely; the transponder still works. You can hear ATC on the standby radio but cannot transmit. ATC has not acknowledged any problem. The private airstrip lies outside controlled airspace and has no radio. There is a suitable uncontrolled aerodrome 12 NM ahead and FIMP is 10 NM behind. Your passenger is anxious and asks you to continue.
1. What are your immediate actions and radio-failure obligations?
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Set the transponder to 7600 immediately so ATC can identify the failure, and continue to fly the aircraft. Do not climb into cloud or enter controlled airspace without a clearance. The clearance you received is not a licence to continue as if the radio were working.
For a VFR radio failure, the safe default is to remain VFR and land at the nearest suitable aerodrome. The nearest suitable aerodrome is not necessarily the private strip 45 NM away. FIMP is only 10 NM behind, has emergency services, and can use light signals; the uncontrolled aerodrome 12 NM ahead is also close. Turning back to FIMP is the most defensible choice unless you are already past the boundary and the uncontrolled strip is clearly closer and safer. Continuing to the private strip would add 45 NM with no radio, no ATC, and no emergency services. That is a convenience decision, not a safety decision.
If you can hear ATC but cannot transmit, listen for instructions and light signals, but do not rely on being able to reply. After landing, telephone ATC and report the failure.
2. If you decide to proceed to the uncontrolled aerodrome 12 NM ahead instead of returning to FIMP, what conditions and precautions must you satisfy?
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You may only do this if the aerodrome is genuinely the nearest suitable landing area and you can stay completely clear of controlled airspace. Remain outside the boundary; do not cut the corner. Maintain VMC at all times and use enhanced see-and-avoid, because ATC is no longer providing traffic separation.
Squawk 7600, monitor the standby radio for relayed instructions, and keep a listening watch on the appropriate frequency. Do not enter any controlled airspace, even if it would shorten the route. Confirm the aerodrome is usable: surface condition, length, wind, and no other traffic. Because there is no radio at the strip, overfly to check the windsock and the runway before joining. After landing, telephone ATC immediately.
The decision changes if the cloud base or visibility falls, if another aircraft is in the circuit, or if the strip is not clearly suitable. In that case, divert to FIMP rather than pressing on.
3. What would change if the cloud base lowered to 1,500 ft and visibility reduced to 6 km?
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The priority would change from continuing to landing as soon as possible. At 2,500 ft you would have only 1,000 ft between you and cloud base, and 6 km visibility leaves little margin for see-and-avoid in controlled airspace. If you cannot maintain VMC clear of cloud and with the required visibility, you must not continue VFR.
The correct action would be to turn back to FIMP or land at the nearest suitable aerodrome while you still have visual conditions. Do not scud-run under the cloud, and do not climb into cloud without an IFR clearance and instrument qualification. A radio failure does not override weather minima. If the weather is deteriorating, declare the situation by transponder and land at the nearest safe aerodrome; the private strip is no longer a reasonable destination.