Mayday (distress signal) - AbsoluteAstronomy.com

Mayday is an emergency procedure word

Procedure word

Procedure words or prowords are words or phrases limited to radio telephone procedure used to facilitate communication by conveying information in a condensed standard form. - OUT :...

used internationally as a distress signal

Distress signal

A distress signal is an internationally recognized means for obtaining help. Distress signals take the form of or are commonly made by using radio signals, displaying a visually detected item or illumination, or making an audible sound, from a distance....

in voice procedure

Voice procedure

Voice procedure includes various techniques used to clarify, simplify and standardize spoken communications over two-way radios, in use by the military, in civil aviation, police and fire dispatching systems, citizens' band radio , etc....

radio communications. It derives from the French venez m'aider, meaning "come help me".

It is used to signal a life-threatening emergency primarily by mariners and aviators but in some countries local organisations such as police

Police

The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...

forces, firefighters, and transportation organizations may also use the term. The call is always given three times in a row ("Mayday Mayday Mayday") to prevent mistaking it for some similar-sounding phrase under noisy conditions, and to distinguish an actual Mayday call from a message about a Mayday call.

Mayday calls

A mayday situation is one in which a vessel, aircraft, vehicle, or person is in grave and imminent danger and requires immediate assistance. Examples of "grave and imminent danger" in which a mayday call would be appropriate include fire, explosion or sinking.

Mayday calls can be made on any frequency, and when a mayday call is made no other radio traffic is permitted except to assist in the emergency. A mayday call may only be made when life or craft is in imminent danger of death or destruction. Mayday calls are made by radio, such as a ship or aircraft's VHF radio. Although a mayday call will be understood regardless of the radio frequency on which it is broadcast, first-line response organisations, such as coast guard

Coast guard

A coast guard or coastguard is a national organization responsible for various services at sea. However the term implies widely different responsibilities in different countries, from being a heavily armed military force with customs and security duties to being a volunteer organization tasked with...

and air traffic control

Air traffic control

Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...

, monitor designated channels: marine MF

Medium frequency

Medium frequency refers to radio frequencies in the range of 300 kHz to 3 MHz. Part of this band is the medium wave AM broadcast band. The MF band is also known as the hectometer band or hectometer wave as the wavelengths range from ten down to one hectometers...

on 2182 kHz

2182 kHz

The radio frequency of 2182 kHz is the international calling and distress frequency for maritime radiotelephone communications on the marine MF bands.- Transmission modes :...

; marine VHF radio

Marine VHF radio

Marine VHF radio is installed on all large ships and most seagoing small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas, and operates in the VHF frequency range, between 156 to 174 MHz...

channel 16 (156.8 MHz); and airband

Airband

Airband or Aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as VHF, or phonetically as "Victor"...

frequencies of 121.5 MHz and 243.0 MHz. A mayday call is roughly equivalent of a Morse code

Morse code

Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

SOS

SOS is the commonly used description for the international Morse code distress signal...

, or a telephone call to the emergency services. When they receive a mayday call the coast guard may launch lifeboat

Lifeboat (rescue)

A rescue lifeboat is a boat rescue craft which is used to attend a vessel in distress, or its survivors, to rescue crewmen and passengers. It can be hand pulled, sail powered or powered by an engine...

s and helicopter

Helicopter

A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

s to assist the ship that is in trouble. Other ships that are nearby may divert course to assist the vessel broadcasting the mayday.

Making a hoax mayday call is a criminal act in many countries because of the danger to the rescuers' lives that a search-and-rescue operation can create, the potential for real emergencies elsewhere, as well as the very high costs of such rescue efforts. For example, making a false distress call in the United States is a federal crime carrying sanctions of up to six years imprisonment, and a fine of $250,000. The coast guard

Coast guard

can be contacted in situations that are not emergencies (out of fuel, etc.) by calling "Coastguard, Coastguard, Coastguard, this is (name of vessel)", on VHF channel 16. In many countries special training and a licence are required to use a mobile radio transmitter legally, although anyone may legally use one to summon help in a real emergency.

The recommended distress call format includes the word "mayday" spoken three times, followed by the vessel's name or call sign

Call sign

In broadcasting and radio communications, a call sign is a unique designation for a transmitting station. In North America they are used as names for broadcasting stations...

, also spoken three times, then "mayday" and the name or call sign again. Vital information, including the position, nature of the emergency, assistance required and the number of people on board, should follow. A typical message might be:
If a mayday call cannot be sent because a radio is not available a variety of other distress signal

Distress signal

s and calls for help

Call for Help

Call for Help, also known as CFH, was a computer-themed television program that first aired exclusively on TechTV , a cable and satellite television network focused on technology, and then aired on G4techTV Canada and the HOW TO Channel in Australia...

can be used. A mayday can be sent on behalf of one vessel by another, using a convention called a mayday relay (see below).

Civilian aircraft making a mayday call in United States airspace are encouraged to use the following format (omitting any portions as necessary for expediency or where they are irrelevant):
Civilian aircraft in the UK and Europe are encouraged to use the following format:
If unable to establish voice radio communications with air traffic control, aircraft wishing to declare an in-flight emergency should set their radar transponder (squawk) to code 7700.

Mayday protocol summary

MAYDAY, MAYDAY, MAYDAY, This is (name of vessel repeated three times)
MAYDAY, MY POSITION IS (give your GPS latitude and longitude or compass bearing from a well known object)
I AM (state problem such as on fire, sinking, etc.) WITH (number of) PERSONS ON BOARD, I REQUIRE IMMEDIATE ASSISTANCE

History

The Mayday callsign was originated in 1923 by Frederick Stanley Mockford

Frederick Stanley Mockford

Frederick Stanley Mockford was the originator of the uniform "distress call" MAYDAY. He was a senior radio officer at Croydon Airport in London...

(1897–1962). A senior radio officer at Croydon Airport

Croydon Airport

Croydon Airport was an airport in South London which straddled the boundary between what are now the London boroughs of Croydon and Sutton. It was the main airport for London before it was replaced by Northolt Aerodrome, London Heathrow Airport and London Gatwick Airport...

in London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

, Mockford was asked to think of a word that would indicate distress and would easily be understood by all pilots and ground staff in an emergency. Since much of the traffic at the time was between Croydon and Le Bourget Airport

Le Bourget Airport

Paris – Le Bourget Airport is an airport located in Le Bourget, Bonneuil-en-France, and Dugny, north-northeast of Paris, France. It is now used only for general aviation as well as air shows...

in Paris

Paris

Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

, he proposed the word "Mayday" from the French m’aider.
"Venez m'aider" means "come help me."

Other urgent calls

Mayday is one of a number of words used internationally as radio code words to signal important information. Senders of urgency calls are entitled to interrupt messages of lower priority. As with Mayday the use of these terms without proper cause could render the user liable to civil and/or criminal charges.

Each of these urgency calls is usually spoken three times; e.g., "Pan-pan, Pan-pan, Pan-pan."

Mayday relay

A Mayday relay call is made by one vessel on behalf of a different vessel which is in distress. If a vessel makes a Mayday call and it is not acknowledged by the coastguard after a single repetition and a two-minute wait a vessel receiving the Mayday call should attempt to contact the coastguard on behalf of the Mayday vessel by broadcasting a Mayday relay on their behalf.

A Mayday relay call should use the callsign of the transmitting vessel but give the name and position of the Mayday vessel.

Mayday relay calls can be used to summon help for a vessel which is either too far offshore to contact the coastguard directly or without radio capabilities (though most vessels above a certain size or crew complement are legally required to carry two-way radio equipment, such equipment can potentially be damaged or destroyed).

Pan-pan

In radiotelephone communications, a call of three repetitions of pan-pan is used to signify that there is an urgency on board a boat, ship, aircraft or other vehicle but that, for the time being at least, there is no immediate danger to anyone's life or to the vessel itself. This is referred to as...

(from the French: panne – a breakdown) indicates an urgent situation of a lower order than a "grave and imminent threat requiring immediate assistance", such as a mechanical breakdown or a medical problem. The suffix medico used to be added by vessels in UK 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

Geneva Conventions

The Geneva Conventions comprise four treaties, and three additional protocols, that establish the standards of international law for the humanitarian treatment of the victims of war...

. "Pan-pan medico" is no longer in official use.

Declaring emergency

Sometimes the phrase "declaring emergency" is used in aviation. This is the same as calling "Mayday". For example Swissair Flight 111

Swissair Flight 111

Swissair Flight 111 was a Swissair McDonnell Douglas MD-11 on a scheduled airline flight from John F. Kennedy International Airport in New York City, United States to Cointrin International Airport in Geneva, Switzerland...

radioed "Swissair one eleven heavy is declaring emergency" on discovering their situation.

Securite

When a marine radio transmission begins with "Sécurité, sécurité, sécurité" , it means that what follows is important safety information. The most common use of this is by coast radio stations before the broadcast of navigational warnings and meteorological information.It is normal practice to...

(icon;
from French sécurité — safety) indicates a message about safety, such as a hazard to navigation or weather information.

Silence

The following calls may be made only by the vessel in distress or the responding authority:

Seelonce Mayday or Seelonce Distress means that the channel may only be used by the vessel in distress and the coastguard (and any other vessels they ask for assistance in handling the emergency). The channel may not be used for normal working traffic until 'seelonce feenee' is broadcast.

The expressions Stop Transmitting — Distress and Stop Transmitting — Mayday are the aeronautical equivalents of Seelonce Mayday.

Seelonce Feenee (French: silence fini — silence finished) means that the emergency situation has been concluded and the channel may now be used normally. The word prudonce (prudence caution) can also be used to allow restricted working to resume on that channel.

Distress Traffic Ended is the aeronautical equivalent of seelonce feenee.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.