^ "Navigation Center: Radio Information for Boaters".The format for the "seelonce feenee" is MAYDAY, All stations x3, this is x3, date and time in UTC, distressed vessels MMSI number, distressed vessels name, distressed vessels call sign, SEELONCE FEENEE. "Distress traffic ended" is the aeronautical equivalent of "seelonce feenee". "Seelonce feenee" (from French silence fini, 'silence finished') means that the emergency situation has been concluded and the channel may now be used normally. The format for a "seelonce mayday" is MAYDAY, All Stations x3 or x3, this is, SEELONCE MAYDAY. "Seelonce distress" and "prudonce" are no longer in use since ITU WRC-07. The expression "stop transmitting – mayday" is an aeronautical equivalent of "seelonce mayday". "Seelonce mayday" and "seelonce feenee" may only be sent by the controlling station in charge of the distress. The channel may not be used for normal working traffic until "seelonce feenee" is broadcast. "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. Cases of pilots using phrases other than "pan-pan" and "mayday" have caused confusion and errors in aircraft handling. However, the International Civil Aviation Organization recommends the use of the standard "pan-pan" and "mayday" calls instead of "declaring an emergency". 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. Sometimes the phrase "declaring emergency" is used in aviation, as an alternative to calling "mayday".
"Pan-pan medico" is no longer in official use. The suffix "medico" used 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. " 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". Making a false distress call is a criminal offence in many countries, punishable by a fine, restitution, and possible imprisonment. Mayday, Mayday, Mayday (Name of station addressed) Aircraft call sign and type Nature of emergency Weather Pilot's intentions and/or requests Present position and heading, or if lost then last known position and heading and time when aircraft was at that position Altitude or Flight level Fuel remaining in minutes Number of people on board Any other useful information. Additionally, a mayday call can be sent on behalf of one vessel by another this is known as a mayday relay.Ĭivilian 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):
If a mayday call cannot be sent because a radio is not available, a variety of other distress signals and calls for help can be used. Mayday calls Ī noise-reduced, condensed version of the above MV Summit Venture collision call. In 1927, the International Radiotelegraph Convention of Washington adopted the voice call "mayday" as the radiotelephone distress call in addition to the SOS radiotelegraph (Morse code) signal.
#WHAT DOES RADIO SILENCE MEAN CODE#
The previous distress call had been the Morse code signal SOS, but this was not considered suitable for voice communication, "wing to the difficulty of distinguishing the letter 'S' by telephone". The term is unrelated to the holiday May Day.įollowing tests, the new procedure word was introduced for cross-Channel flights in February 1923. 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'aidez ("help me") or m'aider (a short form of venez m'aider, "come help me"). 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. 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. 3.3 Silencing other communications traffic.