The Mayday call originated in the 1920s. A senior radio officer at London's Croydon Airport in London, Frederick Stanley Mockford, was the first to use this signal to indicate emergency situations.

Where did May Day come from?

Mayday got its start as an international distress call in 1923. It was made official in 1948. It was the idea of Frederick Mockford, who was a senior radio officer at Croydon Airport in London. He came up with the idea for “mayday" because it sounded like the French word m'aider, which means “help me."

What is the difference between SOS and mayday?

While it has the same meaning as S.O.S. – "Save our Souls" – "Mayday" is more commonly used to convey an emergency verbally. S.O.S. is used less often these days since it was used mostly to indicate an emergency situation when transmitted by Morse code – three dots followed by three dashes and three more dots.