'Tree-niner-fife': The Global Language of Pilots

Because a misunderstanding between a pilot and a controller can lead to catastrophe, the formation of a common language has made flying much safer. FG/Bauer-Griffin/Getty Images

You might be surprised to learn that if you're taking an airline flight from a U.S. airport to some international destination, regardless of whether it's Paris, Bogota or Beijing, your pilot will be talking to air traffic controllers on the ground in those countries in the same language, English.

But it's not a version of English that would make much sense to you, the passenger, since it's laden with numbers, acronyms and arcane terminology, such as "Center Control, Papa November tree-niner-fife at tree-tree-zero." (That example, taken from Oklahoma State University aviation training materials, appears in "The Handbook of English for Specific Purposes.")

The reason is that according to a set of standards and recommended practices adopted in 2003 by the International Civil Aviation Organization, pilots on international flights and air traffic controllers on their routes are required to speak a specialized version of the language known as Aviation English when they communicate over the radio.

Elizabeth Mathews, a linguist and assistant professor in the Department of Applied Aviation Science at Embry-Riddle Aeronautical University, explained in a phone interview that Aviation English is required throughout the world, because it wouldn't be practical for a pilot to have to know all the different languages spoken in countries where he or she has to fly.

The Evolution of a Common Language

How pilots communicate has evolved since they first began using radios in the early 1900s, according to Dominique Estival, a Western Sydney University linguist and co-author of the book "Aviation English: A lingua franca for pilots and air traffic controllers." Initially, they used the Q Code, a sort of simplified version of Morse code, and eventually, took to speaking the letters rather than tapping them out. Between the World Wars, pilots began using the International Telecommunications Union's phonetic alphabet, in which a code word was assigned to each letter — such as "alpha" for A, and "bravo" for B — to avoid having someone mishear a letter.

English has been the dominant language in aviation since the end of World War II, in part because the victorious United States became a power in both the airline industry and aircraft manufacturing. But ICAO, an agency with 188 member countries, didn't initially require the use of English by pilots and controllers. Instead, for decades, it took the position that pending the development and adoption of a more suitable form of speech, English was the recommended — but not mandated — language to use.

But there wasn't any requirement for aviation personnel to develop proficiency in English. In 1996, airliners from Saudi Arabia and Kazakhstan collided in midair near New Delhi, India, and killed 351 people. According to this report on the crash, tapes of radio communications showed that the Kazakh flight crew had difficulty understanding air traffic control's instructions, which may have been a factor in the disaster.

That led India to approach the ICAO and propose that the language rules be tightened, Mathews said. ICAO eventually enacted new rules requiring the use of Aviation English and mandating that pilots and air traffic controllers on international routes pass tests to demonstrate proficiency.

Standard Phraseology

Aviation English doesn't have anywhere near as many words and phrases as the version of the language that most of us speak, but in some ways it's much more complex and nuanced. Because a misunderstanding between a pilot and a controller can lead to catastrophe, Aviation English relies upon a standard phraseology, which Estival defines in an email as "a prescribed, highly constrained set of phrases to be used insofar as possible." As this 2014 Aerosavvy.com article explains, even the pronunciation of numbers should follow precise standards for optimum clarity, so that 4, for example, is spoken as "FOW-er," while 3 becomes "tree" without the 'h' sound.

But that vocabulary doesn't necessarily cover every situation that can occur in aviation. In those instances, pilots and controllers can use "plain" language, Mathews explained. After a US Airways airliner that had taken off from New York's LaGuardia Airport collided with a flock of birds in January 2009 and suffered engine failure, for example, pilot Chesley "Sully" Sullenberger diverged from the standard ICAO glossary, and simply told the controller, "We're going to be in the Hudson," as this National Public Radio story details.

There are a lot of different training programs around the world for learning Aviation English, according to Jennifer Roberts, an Aviation English Specialist in the College of Aeronautics at Embry-Riddle. But finding a good course isn't necessarily easy.

"The most important consideration in training is the particular teaching approach utilized," Roberts explains in an email. "Many programs are available in the world, but few adhere to best practices as outlined by ICAO. Notably, content-based language instruction is the recommended method, meaning that students will learn English with content which is relevant, interesting, and applicable to the domain in which they will use the language. To illustrate, think of the reaction you would have if you utilized content about, for example, art history, in a room full of commercial airline pilots needing to improve their radiotelephony skills. In addition, ICAO recommends that the training is conducted by someone with a post-graduate degree in Applied Linguistics or TESOL (teaching English to speakers of other languages), and with aviation familiarity. There aren't many English teachers flying aircraft out there in the world, so finding quality instructors is definitely a challenge."

Aviation English has made flying a lot safer, according to Estival. "It's been very successful in reducing misunderstandings and miscommunications," she explains. "It would be hard to quantify the number of accidents/incidents that have been avoided, as all accidents always have a combination of causal factors."

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