An unfamiliar turn of phrase, a heavy accent or an overly abbreviated command in the exchange between pilots and air traffic controllers can have deadly consequences.
In fact, miscommunication has contributed to at least two airline disasters, including the deadliest ever, and the language barrier is being investigated as a possible cause in this week’s collision of an airliner and a cargo plane over India.
The problem has so frustrated pilots and air traffic controllers around the world that a group of them is trying to devise a standardized phrase book.
“It’s so important. No matter what you say, no matter where in the world you say it, you have to be able to be understood,” said Tom Kreamer, a USAir pilot who handles safety and standards issues with the international and U.S. pilot associations.
There are two issues, as some pilots see it: the need for a standard language, and the need for a standard choice of words within that language.
Generally, English serves as the de facto language of aviation worldwide. Some countries, like Holland, forbid the use of any language but English, while other countries, like France, allow the local language to be used between the ground and their national airline.
Control tower conversations in another language can be unnerving to some pilots, leaving them guessing what’s going on around their plane.
“I know where I am at any given time,” Kreamer said. “If a controller speaks to another aircraft in another language, I have no way of knowing where that aircraft is and what it’s going to do.”
But even a common language isn’t enough.
The 1990 crash of an Avianca jet in Cove Neck, N.Y., might have been averted but for a poor choice of words.
The plane went down, killing 73 people, when it ran out of fuel while circling the airport. The co-pilot, whose native language was Spanish, had told controllers, in English: “We’re running out of fuel.” Had he declared a “fuel emergency,” he would have been given priority to land.
Miscommunication was also blamed for the 1977 collision between a Pan Am jet and a KLM airliner at a foggy airport in Tenerife, Spain. The deadliest accident in aviation history, it killed 582 people.
The Pan Am jet was taxiing, and the KLM jet was asked to line up and wait. Instead of staying put until it got clearance, the KLM tried to take off and struck the Pan Am jet. The problem may have been a basic misunderstanding of the words, or perhaps a failure to hear them at all.
An American Airlines pilot who spoke on condition of anonymity said that on his first trip into Paris, the controller abbreviated his instructions, not knowing the pilot was unfamiliar with the local lingo: “Cleared Orly 2-4.”
“We just looked at each other and thought, ‘What is he talking about?”’ the pilot recalled.
When they asked to have the instruction repeated, they were given the full, standard instruction that clearly told them to go into a holding pattern on the flight path into Orly Airport and to expect clearance to land at 6:24 a.m.
But even conversation with English-speakers can be troublesome.
“I’ve had pilots ask me to slow down because they’re from the South and didn’t understand me as fast as I spoke,” said Barry Krasner, president of the National Air Traffic Controllers Association and a former controller in New York City.
There is a standard set of phrases recommended by the Montreal-based International Civil Aviation Organization, but compliance is optional.
For the past 18 months, a committee of pilots, controllers and government officials has been trying to develop a standard set of aviation terminology. It plans to issue a new guidebook for the ICAO within two years. The hope is that in picking the best phrases, they will be followed more closely.