Lost comms on the way to Class C
You are flying a Piper PA-28 VFR from a Class D aerodrome to a destination aerodrome inside a Class C TMA. Cruise is 4,500 ft AMSL, QNH 1018, CAVOK, wind 240/12. You filed a VFR flight plan and are squawking 7000 with a serviceable Mode S transponder. About five minutes after leaving the Class D control zone, still in Class G and 12 NM from the Class C boundary, the COM radio fails: you can neither transmit nor receive on either of the two frequencies you try, and the headset and PTT have been checked. The handheld in your flight bag has a flat battery and there is no other radio on board. There is a small Class G aerodrome with a hard runway 8 NM ahead, and your destination is 35 NM ahead. You are in VMC with at least 10 km visibility and cloud well above you. Fuel is sufficient for another two hours.
1. What do you do in the first few minutes after recognising the failure?
Read the worked answer
Treat it as a lost-communication event and act on three axes at once.
- Tell ATC without voice. Select squawk 7600 on the Mode S transponder. This is the internationally recognised lost-communication code and is the primary signal available to you; it also flags the problem to any unit watching your track.
- Fly the aircraft and keep VMC. Stay clear of cloud, keep a good lookout, and remain in Class G. Do not let the troubleshooting distract you from attitude, terrain and traffic.
- Try to restore communications. Second radio or frequency, volume/squelch, intercom and headset plugs, PTT, and the handheld if you can power it. If a mobile phone has signal and you know the ATC number, a call is a useful backup, but never rely on it.
- Decide where to go. With no clearance and no radio, the practical plan is to land as soon as reasonably practicable at a suitable aerodrome - the Class G aerodrome 8 NM ahead is ideal - then telephone the ATS unit from the ground.
The one thing you must not do is drift on towards the TMA hoping the clearance will be assumed.
2. Can you continue into the Class C TMA as planned? Explain what a clearance means here and what your alternatives are.
Read the worked answer
No. A VFR flight in Class C requires an explicit ATC clearance, and radio failure does not create one. The transponder code tells ATC you have a problem; it does not authorise entry. Entering a TMA without a clearance is a serious infringement regardless of how benign the weather is.
Alternatives, in order of preference:
- Land at the Class G aerodrome 8 NM ahead. Land, telephone the TMA unit, explain the failure, and either obtain a new clearance by phone (some units will coordinate this) or refile and continue when the radio is fixed.
- Return to the Class D aerodrome only if you can comply with that aerodrome's procedures; a Class D CTR also needs a clearance, and with no radio you would depend on light signals from the tower. Learn them: steady green = cleared to land; flashing green = return for landing, to be followed by steady green; steady red = give way to other aircraft and continue circling; flashing red = aerodrome unsafe, do not land; alternating red and green = danger, be on the alert.
- Divert to another aerodrome outside controlled airspace if it is closer and safer.
Judgement point: the weather lets you stay VMC, but VMC is only one of the two conditions - the other is the clearance you no longer have.
3. What are your obligations regarding the flight plan and the aircraft once you are on the ground?
Read the worked answer
Close the loop, because an open flight plan can start a search.
- Notify ATS. From the ground, telephone the unit that accepted the flight plan (or the destination ATS) and state that you have landed safely at a different aerodrome, give the time, and ask them to close or amend the plan. If the plan is not closed, the alerting service will progress through the emergency phases - uncertainty, then alert, then distress - and a search may be launched for an aircraft that is sitting safely on the ground.
- Explain the failure. Tell the unit what happened and where you are; if you subsequently wish to continue, they can coordinate a clearance or a new plan.
- Enter the defect in the technical log. A failed COM radio is an aircraft defect and must be recorded so the aircraft is not dispatched again until it is rectified. If the aerodrome has no maintenance, seek advice before further flight; in many cases a radio failure makes the aircraft unfit for controlled-airspace operations.
- Consider a report. Some States require an occurrence report for a communication failure that affected the safety of the flight; at minimum, a written note protects you if questions are asked later.
Judgement point: the incident is not over when the wheels stop; administrative closure is part of the pilot's duty.