'Mayday' emergency call originated from m'aidez

In 1923, when international radio communication was in its infancy, the senior radio officer at the now-closed Croydon Airport – the first of its kind in the world to employ an air-traffic control system – was asked to come up with an easily memorable word to indicate that an aeroplane had an emergency.

It had to be easy to pronounce and easy to understand, even in emergency conditions or where transmission or reception is poor.

Frederick Stanley Mockford came up with “Mayday”, which he derived from m’aidez, the imperative pronominal form of the French verb aider or “to help”.

Part of his inspiration came from serving in France during the First World War plus hearing regular chatter from planes flying from Croydon to Le Bourget Airport on the outskirts of Paris.

Four years later, the International Radiotelegraph Convention of Washington DC confirmed Mayday as the official voice distress call, replacing the SOS Morse code message.

Today, any vessel that makes a Mayday call repeats the word three times so it is not mistaken for any similar- sounding phrase under noisy conditions, and to distinguish an actual Mayday call from a message that mentions a Mayday call.

A less-serious emergency call is “pan-pan”, which indicates an aircraft or vessel needs help, but that no one aboard is in immediate danger. This also comes from the French – panne, which indicates a breakdown or failure.

In fact, French words and pronunciations are commonly used in important safety and emergency situations to separate them from standard English radio chatter.

Sécurité, for example, is used to indicate that the following message contains important safety information, such as a hazard to navigation or weather information.

Equally, the French pronunciation of silence (“see-lonce”) indicates that a particular radio channel may only be used by a vessel in distress and responding authorities.

All other vessels should remain silent until otherwise informed – usually with the French words silence fini (“see-lonce fee-nee”), indicating that the emergency is over, or silence prudence (“silence proo-donce”), meaning that the channel can be used again with care.