Tango, Bravo
Why pilots say Mayday and 9 other codewords everyone should know
Published on August 12, 2026
In situations where clear communication is paramount, especially when lives are at stake, professionals often rely on standardized codewords and phonetic alphabets designed to prevent confusion. Either from movies or from personal experience, it's probable that you've heard at least some of these before, and many have found their way into everyday conversation. Let's find out how many of these code expressions you can recognize.
Mayday
Mayday is the international distress call used when the sender is in immediate, life-threatening danger. Pilots and mariners use it to signal that they require urgent assistance due to situations such as engine failure, fire, flooding, or medical emergencies.
The word was introduced in 1923 by British radio officer Frederick Stanley Mockford, who based it on the French phrase m'aider, meaning "help me," in an attempt to make it internationally recognizable. Hearing this transmission immediately alerts emergency responders that every second counts.
Pan-Pan
Not every emergency is severe enough to warrant a mayday call. When a crew faces a problem that is urgent but not immediately life-threatening, the appropriate codeword is Pan-Pan.
Like mayday, it comes from French: it derives from panne, meaning a breakdown or mechanical failure. A Pan-Pan call might be used if an aircraft loses an engine but can still fly safely, or if a ship experiences equipment problems while remaining under control. It tells responders that assistance is needed, but that the situation has not yet become critical.
SOS
Few emergency signals are as universally recognizable as SOS. Contrary to popular belief, the letters do not officially stand for "Save Our Ship" or "Save Our Souls." It was adopted in 1906 because SOS is an extremely simple, easy-to-transmit, and unmistakable pattern in Morse code.
SOS remains one of the world's most enduring distress signals, and it's still recognized by rescue organizations all around the globe.
NATO Alphabet
In the NATO phonetic alphabet, each letter is assigned a unique word to eliminate confusion when radio transmissions are distorted by noise or poor reception. If you've ever heard someone spell a name as "Mike Alpha Romeo Yankee," you've encountered the NATO phonetic alphabet.
The system was officially adopted by NATO in the 1950s and is now widely used by militaries, airlines, emergency responders, and many police departments worldwide. Using it greatly reduces the chance of misunderstanding important information over radio.
Roger
Roger dates back to the early days of radio communication, when the letter R stood for "received." Before the adoption of the NATO alphabet, the US military used Roger instead of Romeo to represent that letter_._
Although modern communications systems have changed and the US military has fully embraced the use of the NATO alphabet, Roger remains standard aviation terminology, and it's one of the best-known radio acknowledgments in the world. It conveys a very simple but important meaning: "I have received and understood your message."
Wilco
Although many people assume Roger and Wilco mean the same thing, they actually convey different messages. Wilco is short for "will comply." In other words, it tells the sender not only that the message was received and understood, but that the instruction will be carried out.
Saying both Roger and Wilco is technically redundant in proper radio communication, since complying necessarily implies understanding, but the combination is often heard in movies and television.
Tango
In the NATO phonetic alphabet, Tango simply represents the letter T. However, US military personnel have also adopted it as a shorthand when referring to a target or a hostile.
This secondary meaning became widely known through military operations in the twentieth century and has since appeared in countless books, films, and video games in phrases like "We've got one Tango moving north."
Oscar Mike
Oscar Mike, NATO for the letters O and M, is military shorthand for "On the Move." It's a quick way of reporting that a unit has begun moving toward its objective.
The expression is especially common in the US military and has become more familiar to the general public through documentaries, memoirs, and films. It's finding its way into civilian life, meaning simply "I'm heading out."
10-4
Ten-codes were developed during the 1930s to allow for brevity and standardization of message traffic in radio communications. They were widely adopted by US public safety departments and by radio enthusiasts.
While the system is being slowly phased out in favor of plain language communications, many local police, fire, and sheriff departments keep using it, and it is still strongly associated with radio culture by the general public. One of the most famous ten-codes is 10-4, meaning "received and understood."
Code Blue
Hospitals around the world use color-coded announcements to communicate emergencies without causing unnecessary panic among patients and visitors. Perhaps the best known is Code Blue, indicating that a patient is experiencing cardiac or respiratory arrest and requires immediate medical assistance.
While some hospitals use their own custom color codes, Code Blue has become so widely recognized that it now appears frequently in television dramas and everyday conversation whenever someone refers to a life-threatening medical emergency.