“MAYDAY”, as a radio call, is a message that is transmitted by a crewman in an aircraft or a ship when a state of distress exists, and immediate help is needed. The use of this word originated in the early 1920’s. It was then that Frederick Mockford, a senior radio officer at Croydon Airport in London, was asked to think about a word that would indicate distress and that would be easily understood by all pilots and ground staff in an emergency. Since much of the traffic at that time was associated with crossings of the English Channel between London’s Croydon Airport and le Bourget in Paris, the word had to suit both English and French tongues. He proposed the word “Mayday”, which also sounded somewhat like the French word, “m’aider”, meaning “HELP ME!”. The term stuck, and in 1927 the International Radiotelegraph Convention in Washington, officially adopted “MAYDAY” as a replacement for the “SOS” Morse Code message that stood for “SAVE OUR SOLES”.

A secondary radio call of French derivation was also created, this being “PAN-PAN” and it came from the word “PANNE” that is linked to when a “break down” of sorts, has occurred.

It is important to understand when a “MAYDAY” is the message that should be transmitted as opposed to when a “PAN- PAN” should be called.  MAYDAY is used when, in the crew’s opinion, a life-threatening situation either exists or is developing. There is a state of DISTRESS and any bit of help the crew can be offered might help remedy or reduce the impact of the situation.

The word MAYDAY must be uttered THREE times….” MAYDAY, MAYDAY, MAYDAY”. These words get the immediate attention of every station that is on the frequency and ensure a level of radio silence. If possible, the pilot or crewmember calling the MAYDAY, should then provide whatever salient or relevant information that could possibly be of use to those that could help. This would be such knowledge as the aircraft type, the NATURE OF THE PROBLEM and IMMEDIATE INTENTIONS, the present or the last known position and the time that the aircraft was there, the altitude or flight level, heading, fuel remaining and endurance and the number of people on board.

The term “PAN –PAN” indicates that a matter of URGENCY exists. These words must also be repeated THREE times….” PAN-PAN… PAN-PAN, …PAN-PAN”. Typically, a PAN-PAN is called because of a mechanical malfunction or some other operational abnormality. This call does not indicate or imply that the aircraft and its crew need life-saving help. What it does do, is advise that there is a state of URGENCY associated with the further operation of the aircraft and that its routing and arrival should be given PRIORITY. The message also serves to establish that the progress of the aircraft will be monitored carefully by ATC.

If there is doubt as to whether it is a MAY DAY or a PAN-PAN that should be called, time should not be wasted by debating the issue. There is no reason why either of these terms cannot be used initially, as they both ensure immediate the temporary radio silence, thus giving the crew an opportunity to convey the nature of their problem. Based on a better assessment or a re-evaluation of the situation, a definite call of a MAYDAY or of a Pan-PAN, one or the other, may then be made.

So, in conclusion, let’s have a look at two real life happenings, one which ended up with the captain ordering a MAYDAY call and the other with the captain opting for a PAN-PAN call.

The first was when a four-engine airliner that had been standing idle at a coastal airport for a few months was being ferried, at night, back to its home base.  Shortly after take-off the number four (outboard right side) engine caught fire. Both the first and the second engine fire extinguishers failed to put the fire out. The fire then spread to the aircraft’s wing where signs that this could “burn away” were showing. The captain had already began turning back, but there was no way the crew could say whether or not they were going to get the aircraft back onto the ground before they could have lost part of the wing and thereby, control of the aircraft. The situation looked incredibly bleak and apart from trying to “blow the fire out” by flying as fast as they possibly could, there was nothing else they could do. Clearly, a state of DISTRESS existed, and a MAYDAY was called. All applicable emergency services and procedures were implemented. With these aids, and the captain’s clear thinking and skill, he and his crew got the aircraft back to the airport for a safe landing, just in the nick of time.

The second event occurred at night when a heavily laden airliner that was departing on a long non-stop international flight, experienced a failure of its main hydraulic systems a few minutes after take-off. The aircraft was carrying maximum fuel, had a full load of passengers on board and was well over its maximum landing weight. There was no way the trip could be continued, as the elevators, ailerons and rudder were then being powered by a standby hydraulic system, used for emergencies only. The return to the departure airport involved a lot of planning and management and the accomplishment of many abnormal checklists. The aircraft had to be sent to a holding area well away from built up areas so that fuel could be jettisoned thereby reducing its weight to below its maximum landing weight. An alternate extension of the flaps then had to be accomplished and the landing gear had to be extended manually. The procedures and calculations for landing with reduced wheel braking capability had to be reviewed and planned for. As per the Captain’s request, emergency and other support vehicles had to be put in place for the arrival of the aircraft. Then too, the Air Traffic Controllers needed to give the aircraftPRIORITYfor the approach, as the airspace was almost saturated with other aircraft that night. Throughout the entire happening, there was a sense of URGENCY due to the high and challenging workload and because certain risks were also involved. There was a definite need to execute every procedure associated with the failures, both timeously and correctly.  However, at no time was the overall safety of the aircraft ever in jeopardy. As a result of the crew’s correct and appropriate thinking, it was a PAN-PAN that was called at the time of the onset of this saga.

In conclusion…. A MAYDAY call is made when a state of DISTRESS exists.

A PAN-PAN call is made when there is a state of URGENCY and PRIORITY is required.