Can the misunderstandings of a few words literally mean the difference between life and death? They can in the airline business. As pilots and air traffic controllers are invisible to one another, they cannot depend on visual cues to facilitate communications. Furthermore, while communicating they also process large amounts of visual information and perform other linguistic tasks- pilots communicating with other crew members, controllers with other flights and both groups monitoring their instruments. Context can be misinterpreted in radio communication. The term “two five zero” can be an altitude, an air speed or a heading. Expecting to receive heading instructions from a controller, and perhaps hearing only the words “two five zero”, a pilot might mistake an altitude clearance for a heading. To compensate for distractions and the ambiguity of context, pilots and controllers use highly formatted exchanges and rely on readback to ensure that the intended meaning has been understood. Despite using readback, miscommunication can occur, especially when the listener’s expectations influence what is heard.
Ambiguity – The Deadly Error
In high-risk situations, such as those that can arise during ATC communication, the result of ambiguity error can be serious. A number of aviation disasters have been largely attributed to problems in communication. In these accidents, visual, contextual and other redundant cues where unavailable, and the speakers failed to recognize or resolve ambiguities in their exchanges.
Consider the following cases.
History’s worst aviation disaster occurred on March 27, 1977 at foggy Tenerife in the Canary Islands, when KLM Royal Dutch Airlines Boeing 747 collided with a Pan American World Airways B-747 killing 583 people. A pilot of the KLM aircraft said that he was “at takeoff”, which the controller assumed to mean that the pilot was ready for takeoff and was awaiting further instructions. Actually, the KLM aircraft was taking off and was about to collide with the Panam aircraft, which was taxiing on the runway toward the KLM aircraft. The grammar of the pilot’s native language, Dutch, interfered with his ability to construct the English statement “I am taking off”, which would have had a different meaning to the controller. Given the challenges of ATC communication and the lack of regulatory specifications for English as the international language of aviation, it is not surprising that a number of aviation accidents have involved non-native English in pilot- controller communications.
On January 25, 1990, the first officer of an Avianca airliner after several holding patterns caused by bad weather, failed to translate to the controller the captain’s statement that the aircraft was in an emergency situation, instead saying “We are running out of fuel.” The controller responded to a low-fuel situation, but not to a low-fuel emergency. The plane impacted terrain at Cove Neck, New York, killing 73 persons aboard the flight.
In 1993, Chinese pilots flying a US built MD-80 tried to land in heavy fog at Urumqi, in northwest China. They were baffled by an audio alarm from the jet’s ground proximity warning system. Just before impact, the cockpit recorder picked up one crew member saying to the other in Chinese: What does pull up mean? The plane hit power lines and crashed, killing 12.
In December 1995, the American Airlines Flight 965 accident near Cali, Colombia, might have been prevented if the Colombian controller had been fluent in English. The Colombian government officially determined flight crew error as the probable error. Nevertheless, the Cali controller said he didn’t have adequate English skills to ask questions when the crew made illogical statements about the plane’s position....