Partial Engine Failure: Distress Versus Urgency
You are pilot-in-command of a PA-28 at 4,500 feet MSL over rolling terrain, 12 nautical miles from a towered airport. The engine begins to run rough; oil pressure is dropping below the green arc, and cylinder-head temperature is rising. You are VFR, in visual meteorological conditions, with two passengers aboard. The engine is still producing partial power, but you cannot maintain 4,500 feet and are descending slowly. The approach frequency is congested with arrival traffic. You have 45 minutes of fuel, the airport is behind a ridge, and there is a flat field 3 miles ahead. You must decide whether to declare a distress or urgency condition, what to transmit, which frequencies and codes to use, and how to update ATC if the situation worsens.
1. Compose the initial call and justify whether to use MAYDAY or PAN PAN.
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Use a distress call: “Mayday, Mayday, Mayday, Cessna [callsign], PA-28, 12 miles [direction] of [airport], 4,500 feet descending, engine rough, partial power, three souls aboard, request vectors to nearest airport.” MAYDAY is justified because you have a failing engine, cannot maintain altitude, and face a possible forced landing over rolling terrain. PAN PAN is for urgency without immediate danger; here the situation is deteriorating and may become a forced landing. Include the nature of the problem, intentions, altitude, and souls on board. If the current frequency is congested, transmit on it first; if no response, go to 121.5. Do not wait for a perfect radio call before turning toward the flat field.
2. What transponder, frequency, and monitoring actions should follow?
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Squawk 7700 and keep Mode C on so ATC and other aircraft see your emergency. If you already have an assigned code, change to 7700 unless ATC has told you otherwise. Transmit on the current approach frequency first, because ATC is already talking to you; if no response, switch to 121.5 and broadcast blind. Monitor 121.5 and the current frequency. If able, set 121.5 in the standby box and use the other radio, if installed. Do not abandon aviate, navigate, communicate: fly the aircraft, pick the field, and then talk. ATC can alert rescue and clear traffic, but only if they know your position and intentions.
3. If descent continues and the engine loses all power, what follow-up transmissions and priorities apply?
Read the worked answer
If the engine loses all power, transmit briefly: “Mayday, Mayday, Mayday, [callsign], engine failure, forced landing [location/field], three souls.” Then prioritize flying the glide, completing the engine-failure checklist, and briefing passengers. Keep 7700 selected and 121.5 monitored. If time permits, give ATC your heading, altitude, and intended landing area so they can coordinate rescue. Do not spend time on a long explanation or trying to fix the radio. If you land off-airport, activate the ELT if installed and call 121.5 or use a cell phone after landing. ATC’s last known position and your 7700/121.5 transmissions help locate you.