Engine failing 12 nm south of Waglan: MAYDAY, then recovery
You are flying a Cessna 172, B-HKD, on a local flight from VHHH over the South China Sea, 12 nm south of Waglan Island at 2,500 ft, in contact with Hong Kong Approach. At 15:40 the engine begins running rough. Oil pressure is falling, oil temperature is rising, there is a smell of burning oil in the cabin, and the engine is delivering only partial power. You are descending about 300 ft/min and cannot hold 2,500 ft. Below you the sea is rough with whitecaps. You have two passengers on board, three life jackets and no raft. Waglan Island is 10 nm to the north; visibility 15 km with scattered cloud at 3,000 ft. Approach has just called: B-HKD, say position and intentions. The engine coughs again and the propeller slows briefly.
1. Decide whether this is a distress or an urgency situation, and give the call you would make.
Read the worked answer
- This is a distress situation. The test is grave and imminent danger requiring immediate assistance: the engine is failing, you cannot maintain altitude, and a ditching is likely. Rough running with the aircraft still holding height would be an urgency (
PAN PAN); losing height with a probable ditching makes it aMAYDAY. - Call:
MAYDAY, MAYDAY, MAYDAY, Hong Kong Approach, B-HKD, B-HKD, B-HKD, MAYDAY, B-HKD, Cessna 172, 12 nm south of Waglan Island, 2,500 ft descending, heading 360, engine failing, partial power, three persons on board, life jackets on, no raft, intending to ditch, request assistance. - Structure: the distress call and the distress message may be combined when time is short. Put identity, position, nature of the emergency and intentions first; those four items let ATC start helping you.
- Flying comes first: trim for the best glide or minimum-sink speed, fly the aircraft, and make one short accurate transmission rather than a long one. Do not give up altitude or heading control to hold the microphone.
2. After the MAYDAY, ATC asks for souls on board, fuel endurance and whether you intend to ditch. Why do these matter, and what else do you do in the cockpit?
Read the worked answer
- Why ATC asks: souls on board tells search and rescue how many people to look for; fuel endurance tells them how long you can stay airborne and when to escalate; your ditching intention decides whether they task surface vessels or helicopters.
- Transponder: select 7700. It marks you on every radar display and saves voice time.
- Cockpit actions: life jackets on and tightened, passengers briefed on ditching, harnesses tight, doors unlatched before contact, ELT armed (activate it if you ditch). Turn towards Waglan or towards any vessel to shorten your exposure in the water, and keep flying the aircraft to minimise the descent rate.
- Radio discipline: stay on the frequency you are already on - the controller already owns your problem. Move to 121.5 only if told to, or if contact is lost.
- Update ATC whenever the situation materially changes: better power, faster descent, or a change of ditching point.
3. The engine recovers, you can hold 2,000 ft and Waglan is 10 nm ahead. ATC asks: `B-HKD, do you wish to cancel distress?` What do you say and do?
Read the worked answer
- Transmit the cancellation explicitly:
MAYDAY, B-HKD, cancel distress, engine power recovered, maintaining 2,000 ft, 10 nm south of Waglan Island, request onward clearance. - Why it must be explicit: until you cancel, ATC treats you as an aircraft in distress, holds or diverts other traffic and has alerted search and rescue. Only you can end it, and you should do so as soon as the grave and imminent danger has passed so that normal service can resume and SAR can stand down.
- If the problem has not gone away: do not cancel. Downgrade to urgency instead -
PAN PAN, PAN PAN, PAN PAN, Hong Kong Approach, B-HKD, ...- and state what is still wrong (rough running, limited power) so ATC keeps a watching brief and priority handling. - After cancellation: keep the frequency, expect ATC to ask for intentions, and expect to be given priority until you are on the ground. If the engine misbehaves again, re-declare immediately - there is no penalty for a second MAYDAY, and waiting is how a recoverable problem becomes an accident.