Emergencies and Urgency Communications
Emergencies and urgency communications
Distress and urgency traffic carries absolute priority and has a fixed format. The exam tests the distinction between them, the message structure, and the phraseology for imposing and lifting radio silence.
Distress versus urgency
MAYDAY, transmitted three times, is for grave and imminent danger requiring immediate assistance - fire, engine failure, ditching. PAN PAN, three times, covers a situation concerning safety that does not yet require immediate assistance - a sick passenger, a failed generator, a doubtful gear indication. The priority order is distress, urgency, direction-finding, safety, other.
Distress message
MAYDAY MAYDAY MAYDAY, station addressed, callsign three times, nature of distress, intentions, position, level and heading, other information. If time is short, transmit what you have and supplement later. If you are already in contact with a unit, stay on that frequency; switch to 121.5 only when contact has been lost.
Silence and closure
Any station may impose silence with 'STOP TRANSMITTING, MAYDAY'. When the incident is closed the controlling station transmits 'DISTRESS TRAFFIC ENDED'. Do not resume routine calls until you hear that phrase or ATC releases the frequency.
Worked example
Rough-running engine, no fire, diversion likely: PAN PAN three times, callsign, nature of the problem, intention to divert to the nearest aerodrome, position, level, persons on board. If the engine then fails, upgrade on the same frequency with MAYDAY three times - never leave a working frequency to make a distress call elsewhere.
Traps
Saying MAYDAY only once; abandoning a working frequency for 121.5; omitting position; forgetting to cancel or close the distress; making an urgency call without stating intentions, which leaves the controller unable to help.