Warning: The following audio content may not be suitable for all listeners. It involves life and death radio transmissions that some listeners might find disturbing.
- Loss, or imminent loss of aircraft control for any number of different reasons
aircraft upset by turbulence;
control surface or structural failure;
engine failure that will lead to a forced landing/ditching/ejection/bailout;
- Or, an onboard fire.
Here are two recordings, released by the F.A.A., of Mayday radio transmissions, along with the response by air traffic services. The first is an exchange between the pilot of a twin-engined Cessna and Jacksonville Center. The second is the radio transmissions of a pilot in a single-engined Cessna and a flight service station specialist at Fort Dodge. (The two incidents are presented in one podcast. I separated the recording of each incident with two brief electronic tones.)
A Pan-Pan call should be used for urgent situations that are not immediately life threatening, but require assistance from someone on the ground. These include, but are not limited to:
- Becoming lost;
- A serious aircraft system failure, that requires an immediate route or altitude change;
- Other emergencies that require immediate attention and assistance from the ground.
This is what the Aeronautical Information Manual has to say about using Mayday and Pan-Pan on the radio.
c. The initial communication, and if considered necessary, any subsequent transmissions by an aircraft in distress should begin with the signal MAYDAY, preferably repeated three times. The signal PAN-PAN should be used in the same manner for an urgency condition.
d. Distress communications have absolute priority over all other communications, and the word MAYDAY commands radio silence on the frequency in use. Urgency communications have priority over all other communications except distress, and the word PAN-PAN warns other stations not to interfere with urgency transmissions.
If you feel your life is in jeopardy, call Mayday. If you need immediate assistance to deal with a serious situation that is not life threatening, call Pan-Pan.
Remember, in either case, it is up to you to fly your airplane to the best of your ability. No one on the ground can do that for you. They may have helpful advice, but it is only advice. You are still the pilot in command.
I’ll have both Mayday and Pan-Pan situations for you to try in the Aircraft Radio Simulator. For now, have you ever heard a distress call on the aircraft radio?
Update: 8 April 2014. There is a audio version of this discussion in my Radar Contact Show #39 “Timing is Everything in ATC Communication”. Here is the link to that show. The discussion of Mayday versus Pan begins at 13 minutes, 32 seconds in the show.