It’s May! And I recently visited the Museum of Flight in Seattle. So have a post about those things!
Perhaps the most widely recognized distress signal is the SOS. This simple Morse code message consists of three dots, three dashes, then three dots. (Although it is often referred to as “SOS”, as there are no breaks between the dots and dashes, the code does not actually make represent those letters). Established by the International Radio Telegraphic Convention in 1906, it has been used ever since to denote an emergency. However, as times and technologies change, so too do our communications. In fact, in 1999, most naval vessels switched to the Global Maritime Distress and Safety System (GMDSS) and no longer have a need to signal SOS. It is still a valuable code in a situation where other signalling methods are not available. For example, a hiker in the mountains without a radio can use a hand mirror to flash the Morse code to searchers.
With the advent of flight and the development of better radio technology, pilots needed a new term for distress signals. This is because “SOS” was not as easily heard over the radio – the letter “s” was hard to make out. In the 1920s, pilots flying between England and France started using the term “mayday” – an easy to pronounce and clearly recognizable word, which also happened to be close to the French word “m’aidez” – “help me”. (The term has nothing to do with the holiday May Day). A pilot signals “mayday” in the event of a life-threatening emergency.
Another code pilots use is “pan-pan”. This word, from the French “panne” (“breakdown”) indicates that an aircraft is in need of assistance, but it is not an immediate danger.
According to the Federal Aviation Administration (FAA):
The initial communication, and if considered necessary, any subsequent transmissions by an aircraft in distress should begin with the signal MAYDAY, preferably repeated three times. The signal PAN-PAN should be used in the same manner for an urgency condition.
Distress communications have absolute priority over all other communications, and the word MAYDAY commands radio silence on the frequency in use. Urgency communications have priority over all other communications except distress, and the word PAN-PAN warns other stations not to interfere with urgency transmissions.
So if you ever find yourself flying a plane and are in need of help, now you know how to ask for it.
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