Mayday

 ( Emergency Communication ) 

Mayday is an emergency procedure word used internationally as a distress signal in Voice procedure Radio.

It is used to signal a life-threatening emergency primarily by aviators and mariners, but in some countries local organizations such as firefighters, police forces, and transportation organizations also use the term. Convention requires the word be repeated three times in a row during the initial emergency declaration ("Mayday mayday mayday").

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History The "mayday" procedure word was conceived as a distress call in the early 1920s by Frederick Stanley Mockford, officer-in-charge of radio at Croydon Airport, England. He had been asked to think of a word that would indicate distress and would easily be understood by all pilots and ground staff in an emergency.

(1977). 9780950322438, London Borough of Sutton Libraries and Arts Services. ISBN 9780950322438

Since much of the air traffic at the time was between Croydon and Le Bourget Airport in Paris, he proposed the term "mayday", the phonetic equivalent of the French m'aider.

The phrase itself does sacrifice grammatical accuracy in favor of communicability and recognition. Looking through the lens of French grammar, it may be a short form of venez m'aider, "come and help me"). Venez m'aider is the closest phonetic phrase to "mayday", but the technically accurate stand alone reflexive imperative conjugation would be aidez-moi.

Following tests, the new procedure word was introduced for English Channel flights in February 1923. The previous distress call had been the Morse code signal SOS, but this was not considered suitable for voice communication, "owing to the difficulty of distinguishing the letter 'S' by telephone". In 1927, the International Radiotelegraph Convention of Washington, D.C. adopted the voice call "mayday" as the radiotelephone distress call in addition to the SOS radiotelegraph (Morse code) signal.

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Mayday calls If a mayday call cannot be sent because a radio is not available, a variety of other and calls for help can be used. Additionally, a mayday call can be sent on behalf of one vessel by another; this is known as a mayday relay.

Civilian aircraft making a mayday call in United States airspace are encouraged by the Federal Aviation Administration to use the following format, omitting any portions as necessary for expediency or where they are irrelevant (capitalization as in the original source):

Making a false distress call is a criminal offense in many countries, punishable by a fine, restitution, and possible imprisonment.

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Other urgent calls

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Pan-pan "Pan-pan" (from the French: panne, 'a breakdown') indicates an urgent situation, such as a mechanical failure or a medical problem, of a lower order than a "grave and imminent threat requiring immediate assistance". The suffix "medico" originally was to be added by vessels in British waters to indicate a medical problem ("pan-pan medico", repeated three times), or by aircraft declaring a non-life-threatening medical emergency of a passenger in flight, or those operating as protected medical transport in accordance with the Geneva Conventions.ICAO Annex 10 V2 Section 5.3 "Pan-pan medico" is no longer in official use.

Tim Bartlett (2025). 9781905104031, The Royal Yachting Association. ISBN 9781905104031

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Declaring emergency Sometimes the phrase "declaring emergency" is used in aviation, as an alternative to calling "mayday". For example, in 1998 Swissair Flight 111 radioed "Swissair one-eleven heavy is declaring emergency" after their situation had worsened, upgrading from the "pan-pan" which was declared earlier.

However, the International Civil Aviation Organization recommends the use of the standard "pan-pan" and "mayday" calls instead of "declaring an emergency". Cases of pilots using phrases other than "pan-pan" and "mayday" have caused confusion and errors in aircraft handling.

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Silencing other communications traffic "Seelonce mayday" (using an approximation of the French pronunciation of silence) is a demand that the channel only be used by the vessel/s and authorities involved with the distress. The channel may not be used for normal working traffic until "seelonce feenee" is broadcast. "Seelonce mayday" and "seelonce feenee" may only be sent by the controlling station in charge of the distress. The expression "stop transmitting – mayday" is an aeronautical equivalent of "seelonce mayday". "Seelonce distress" and "prudonce" are no longer in use since ITU WRC-07.

The format for a "seelonce mayday" is MAYDAY, All Stations x3 or Interfering x3, this is controlling, SEELONCE MAYDAY.

"Seelonce feenee" (from French silence fini, 'silence finished') means that the emergency situation has been concluded and the channel may now be used normally. "Distress traffic ended" is the aeronautical equivalent of "seelonce feenee".

The format for the "seelonce feenee" is MAYDAY, All stations x3, this is controlling x3, date and time in UTC, distressed vessel's MMSI number, distressed vessel's name, distressed vessel's call sign, SEELONCE FEENEE.

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See also

• Aircraft emergency frequency
• CQD
• Global Maritime Distress Safety System
• Sécurité
• Vessel emergency codes

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External links

• Handling Distress and Help Calls
• ACP135(F): Communications Instructions: Distress and Rescue Procedures
• Boating Safety: A VHF Primer, the use and misuse of the VHF
• Transport Canada: Radio Distress Procedures Card TP9878

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