Maybe you are familiar with scenes in movies where a pilot has got into an emergency mid-flight and you hear him shout "Mayday! Mayday! Mayday!". But what does "Mayday" mean? Mayday is an internationally recognized distress call (求救信号), mostly used by pilots and boat captains. The signal can be sent out on any channel by radio communication.
This emergency call originated in the 1920s. At that time, the standard distress call was "SOS" and was typically used by navy captains. The message was sent in Morse code by telegraph. In Morse code, "SOS" is three dots, three dashes and three dots. The signal was unmistakable. However, aircraft pilots use radio calls, so sending out "SOS" could be misheard as other letters, such as "F".
Frederick Stanley Mockford, a radio officer at Croydon Airport in London, was asked to think of a word that would indicate distress. Because of the number of flights that flew between Croydon and Paris, he chose Mayday, as it sounds similar to the French word aider", which means "help me".
Facing a threatening situation, pilots are required to repeat the signal three times in case of radio interference (干扰)or loud background noise. If the pilots don't get a reply within two minutes, they should repeat it. Once they receive a reply, more information including the code of the flight, their current situation and the number of people on board should be reported. Sometimes pilots are directed to a nearby airport or location where they can make an emergency landing. While Mayday signals indicate a life-threatening situation, they do not always end in deaths.
Despite dangers, air travel is still the safest means of transport.
