FYI: How did 'mayday' become the universal distress signal for ships and planes in trouble?

The French often take issue with the dwindling worldwide status of their language - witness the government's furious attempts to stem the surging use of English in the previously Franco-centric European Union. But they can take some comfort in the fact many French expressions have become permanent fixtures in the English lexicon.

Despite its Anglicised appearance, the mayday signal is actually based on a French expression - m'aider, or 'help me'. The phrase was elevated to international status in the 1920s by Frederick Stanley Mockford, a senior radio officer at London's now-defunct Croydon Airport. He was asked to think of a term that would convey an urgent need for assistance and would also be easily remembered by a cosmopolitan bunch of pilots and airport ground staff. Since the majority of the traffic Mockford dealt with was between Britain and France, m'aider, a French term easily pronounced by English speakers, seemed like a good choice.

According to flight (and maritime) tradition, the call is to be used only when a person or vehicle is in immediate danger, from an explosion, fire, hull breach or the like. The radio operator should broadcast a message that starts with the word 'mayday' repeated three times then specify the name and position of the vessel in trouble. This format helps listeners distinguish the distress call from casual mention of the word 'mayday'.

While a distress call can be broadcast on any radio frequency, agencies such as the US Coast Guard and air traffic controllers usually monitor specific channels for emergency messages. Most authorities will immediately launch a rescue operation in response to a mayday signal, so the punishment for crying wolf can be severe. In the US, communications and military officials have launched a campaign to counter a steady rise in prank distress calls. If the perpetrators of these hoaxes are caught, they face up to six years in prison as well as a US$250,000 fine and compensation for any costs incurred by the rescue attempt. Since, according to the US Coast Guard, even a medium-sized ship costs US$2,000 per hour to run, those costs can quickly add up.

Still, false maydays - intentional or otherwise - are a regular occurrence. An aspiring pilot in New Zealand recently sparked a security scare when he left his finger on the microphone button of the light aircraft he was flying. His distress call, which was intended to be a practice, prompted police, fire and ambulance services to descend on a small-town airfield. And, a few years ago, in Denmark, two rescue vessels were sent to scour the Baltic Sea for a ship that turned out to be the creation of a drunk 52-year-old, who called in repeated mayday alarms while playing with toy boats in his bath.

Francophiles will be pleased to know mayday isn't the language's only contribution to emergency terminology. In fact, a number of standard distress phrases have French roots, including 'pan-pan' (from panne, or breakdown), used to describe a situation that's difficult but not dire, and securite, which precedes warnings about weather or navigational hazards.