The topic we will (briefly) approach this week is Miscommunication in Aviation. It comprehends a whole amount of subtopics: misunderstandings, mishearing, pilot X ATC exchanges, and so on… For now, we would like to share with you a brief review of some things that have been written about it.
Steven Cushing, in “Fatal Words: Communication Clashes and aircraft Crashes” illustrates miscommunication events that caused serious crashes.
Many occurrences can be attributed to a clash between individual cognitive and social interactive factors of language.
The book dates back to 1994 and remains one of the best references in the topic still today for its comprehensive search and amount of data gathered and classified in categories, such as problems of reference, problems of inference, problems of repetition, problems with numbers, and so on.
According to Cushing, many occurrences can be attributed to a clash between individual cognitive and social interactive factors of language.
For instance, how do you understand the sentence “Flying planes can be dangerous”?
- Planes that are flying can be dangerous
- The act of flying a plane can be dangerous
Both are possible. And this ambiguity can be a problem, because it is hard to make sure your sentences are going to be interpreted exactly as you thought they would.
Air California 336, in 1981, ironically features this with the misunderstanding of the word “hold”and its both possible meanings. At John Wayne/Orange County Airport in Santa Ana, California, a Boeing 737 was cleared to land at the same time as Air California Flight 931 (another B737) was cleared to taxi into position for take-off, but the controller decided that more time was needed between the two scheduled events and so told the Flight 336 captain to go-around. Flight 336’s captain chose to have his first officer radio for permission to continue landing, but the pilot used the word “hold” to express the requested continuation, inadvertently switching from technical aviation jargon to ordinary English vernacular while speaking to the first officer. The first officer then radioed: “Can we land, tower?” In aviation parlance, “hold” always means to stop what you are now doing. But in ordinary English, “hold” can also mean to continue what you are now doing (as in “hold your course”). The controller’s seemingly self-contradictory instruction to Flight 931 to go ahead and hold at almost exactly the same time further exacerbated the situation, especially in view of the similarity of the two aircraft’s identifying call signs and the consequent uncertainty as to just who was being addressed with that instruction. The resulting confusion led to 34 injuries, four of them classified as serious. The Flight 336 aircraft was destroyed by impact and post-impact fire when it landed with its gear retracted, the pilot having finally decided to follow instructions to go-around, but too late to actually do so. (Cushing, 1994).
Tenerife crash remains the deadliest in aviation history and highlights miscommunication as a root cause.
“On 27 March 1977, the pilot of a KLM Boeing 747 radioed, “We are now at take-off”, as his aircraft began rolling down the runway in Tenerife, the Canary Islands. The air traffic controller mistook his statement to mean that the aircraft was at the takeoff point, waiting for further instructions, and so did not warn the pilot that another aircraft, a Pan American Airways B747 that was invisible in the thick fog, was already on the runway. The resulting crash killed 583 people in what is still the most destructive accident in aviation history. The KLM pilot’s otherwise perplexing use of the nonstandard phrase “at take-off”, rather than a clearer phrase such as “taking-off”, can be explained as a subtle form of what linguists refer to as “code switching”. Careful studies of bilingual and multilingual speakers have shown that they habitually switch back and forth from one of their languages to another in the course of a conversation, not because of laziness or lack of attention, but because of inherent social and cognitive features of how language works, that are still poorly understood.” (Cushing, 1994)
Other problems such as misunderstandings with “to” and “two”, as well as confusion with heading, flight levels, call signs and readbacks are illustrated along the book.
The main recommendation of aviation safety authorities is to be always aware of the situation and possible upcoming events, confirming and disconfirming information as much as needed.
You can also visit http://skybrary.aero/bookshelf/books/2581.pdf for another great book review.