'Tree-niner-fife': The Universal Language of Aviators

It might come as a surprise, but when you board an airline flight from a U.S. airport to any international destination—be it Paris, Bogota, or Beijing—your pilot will communicate with air traffic controllers in those countries using the same language: English.

However, this isn’t the kind of English you’d easily understand as a passenger. It’s filled with numbers, acronyms, and specialized jargon, like "Center Control, Papa November tree-niner-fife at tree-tree-zero." (This example, sourced from Oklahoma State University’s aviation training materials, is featured in "The Handbook of English for Specific Purposes.")

The rationale behind this is rooted in a series of standards and recommended practices established in 2003 by the International Civil Aviation Organization. These guidelines mandate that pilots on international flights and air traffic controllers along their routes must use a specialized form of English, known as aviation English, during radio communications.

Elizabeth Mathews, a linguist and assistant professor in the Department of Applied Aviation Science at Embry-Riddle Aeronautical University, clarified in a phone interview that aviation English is a global requirement. This is because it would be impractical for pilots to learn every language spoken in the countries they fly to.

The Evolution of a Common Language

The way pilots communicate has transformed significantly since the early 1900s when radios were first introduced, as noted by Dominique Estival, a linguist at Western Sydney University and co-author of "Aviation English: A lingua franca for pilots and air traffic controllers." Initially, pilots relied on the Q Code, a simplified Morse code system, and later transitioned to verbalizing the letters instead of tapping them out. Between the World Wars, the International Telecommunications Union's phonetic alphabet was adopted, assigning code words like "alpha" for A and "bravo" for B to prevent miscommunication.

English became the predominant language in aviation after World War II, partly due to the United States' emergence as a leader in both the airline industry and aircraft manufacturing. However, the International Civil Aviation Organization (ICAO), with its 188 member countries, did not initially enforce the use of English for pilots and controllers. For many years, it maintained that English was the suggested, but not compulsory, language until a more suitable alternative could be developed and adopted.

However, there was no mandate for aviation personnel to achieve fluency in English. In 1996, a tragic midair collision between Saudi Arabian and Kazakh airliners near New Delhi, India, resulted in 351 fatalities. Investigations revealed that the Kazakh flight crew struggled to comprehend air traffic control instructions, which likely contributed to the disaster.

This incident prompted India to urge the ICAO to strengthen language regulations, as noted by Mathews. Consequently, the ICAO introduced new rules, making aviation English compulsory and requiring pilots and air traffic controllers on international routes to pass proficiency tests.

Standard Phraseology

Aviation English is far more limited in vocabulary compared to everyday language, yet it is intricate and nuanced in its own way. To prevent catastrophic misunderstandings between pilots and controllers, it relies on a standardized set of phrases. Estival describes this in an email as "a highly regulated, predefined collection of expressions to be used whenever possible." As highlighted in a 2014 Aerosavvy.com article, even number pronunciations follow strict guidelines for clarity—for instance, 4 is pronounced "FOW-er," and 3 becomes "tree" without the 'h' sound.

However, this specialized vocabulary doesn’t account for every possible aviation scenario. In such cases, pilots and controllers can resort to "plain" language, as Mathews explained. For example, after US Airways Flight 1549 struck a flock of birds shortly after takeoff from New York’s LaGuardia Airport in January 2009, pilot Chesley "Sully" Sullenberger deviated from standard ICAO terminology and simply informed the controller, "We're going to be in the Hudson," as detailed in this National Public Radio story.

Globally, numerous training programs exist for mastering aviation English, as noted by Jennifer Roberts, an aviation English expert at Embry-Riddle's College of Aeronautics. However, identifying a high-quality course can be challenging.

"The teaching methodology is the most critical factor in training," Roberts emphasizes in an email. "While many programs are available worldwide, only a handful follow ICAO's best practices. Content-based language instruction is the preferred approach, where students learn English through material that is relevant, engaging, and directly applicable to their field. For instance, imagine using art history content to teach commercial airline pilots improving their radio communication skills. Additionally, ICAO recommends that trainers hold a postgraduate degree in Applied Linguistics or TESOL (Teaching English to Speakers of Other Languages) and have aviation experience. Since few English teachers are also pilots, finding qualified instructors remains a significant challenge."

According to Estival, aviation English has significantly enhanced flight safety. "It has been highly effective in minimizing misunderstandings and communication errors," she states. "While it's difficult to measure the exact number of accidents or incidents prevented, it’s important to note that accidents typically result from multiple contributing factors."