Communication Error in Aviation

Introduction

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. The B- 757 aircraft flew into a mountain and 160 were killed. The controller’s technical language proficiency was inadequate to meet the job requirements, although he was apparently fully trained.

Dealing with ambiguity in ATC communications is even more complex when flight crews, controllers or both are communicating in English that has been acquired as a second language. English is a lexicon of abbreviations, acronyms and jargon and we have many different versions of English. Often English language can be confusing- we have problems with oxymorons, slang, homonyms (to,too,two) and so forth. In early 1995, following several highly publicized accidents, proposals were made to require all airline transport pilots to pass a test of English-speaking proficiency. This lead to the drafting of a standardized test, which included listening, speaking and writing and using model airplanes to demonstrate understanding of flight-maneuver terminology. The FAA has not taken any action to require such testing of non-U.S. pilots flying to the United States. Several U.S. based careers took the initiative to foster training programs for Russian and Chinese controllers at U.S. universities, despite the absence of an international standard addressing skill levels.

Remedies to avoid or reduce the impact of ambiguity error

Training programs to improve controller English skills face a variety of challenges. As skill-level requirements have never been defined, training has emphasized mastery of standardized terminology. Nevertheless, the acquisition and use of language skill is complex and involves learning grammar, pronunciation, intonation and usage. Developing functionality in a foreign language is a difficult task. Effective pilot-controller communication depends on their ability to avoid ambiguity, or at least to resolve ambiguous situations when they occur. If controllers lack adequate English skills, they cannot resolve ambiguous situations by requesting clarification or verification of details, as happened in Cali. Therefore English proficiency needs to exceed the level required to reproduce memorized phrases and terms.

Contrary to the method used in many countries, ATC terminology should be taught not to beginners, but only to students who have at least a relatively advanced knowledge of English. ATC terminology is highly specialized and occurs infrequently in the general language. Jack C. Richards suggests that terminology is best learned in the context of general language in which it is used because knowing a word includes:
Knowing the probability of encountering that word in speech or print;
For many words, knowing the type of words most likely to be associated with the word;
Knowing the limitations imposed on the use of the word according to variations in function and situation; and,
Knowing the syntax associated with the word.
Knowledge of specialized terms is also easier to acquire when aspects have been mastered first, such as principles of word formation and sentence structure. Teaching and testing knowledge of ATC terminology alone turns controllers into parrots, who are handicapped in unusual or stressful ATC situations, rather than skilled users of English who can apply the language in a range of contexts.

One solution to English-proficiency and other communication problems suggested by Cushing is an “intelligent voice interface”, which would provide some callouts automatically; monitor voice transmissions for accuracy, completeness, plausibility and similar factors; and question the speaker as needed before transmitting communications. But, as he acknowledges, we lack the technology and a complete understanding of how language is interpreted by the brain. For the present, he recommends development of other visual back-up systems to voice.

Although many advocate the use of datalink to avoid the complexities of voice communication, it might be a questionable replacement for controlled approaches and other nonroutine situations. Reading and typing English language exchanges in free text, if required for datalink systems, will be a time consuming and challenging linguistic task for non-native speakers. Moreover, datalink and voice interface systems might discourage active monitoring of other flight crews’ and controllers’ voice communication, which often provides additional information. The resulting atrophy of verbal skills may impede the ability to respond to verbal information. So the solution for the moment should be training that will give every pilot and controller the skills to serve as his/her own ‘intelligent voice interface’. Technical systems should be used for back up and augmentation, and should replace voice communication only for routine ATC exchanges.

For air traffic controllers, international English performance requirements should be more clearly defined, and then re-evaluated as new technology is introduced that will change the use of natural language for communication between pilots and controllers. Since international standards have not been developed, countries like Russia, China and some Latin American countries train and certify controllers according to their own standards. Different kinds of programs produce varying results. So international policy and guidance should be developed to avoid dissimilarities in the various national standards.

Despite the lack of an international standard, Russian aviation authorities have been working to develop the necessary standardization, testing and training programs. This process involves testing large numbers of controllers in different regions and observing their performance to establish a minimum proficiency standard that can be applied to all or selected group of controllers based on job requirements. The same process may be used by other countries to establish local and eventually regional standardization, and these standards could ultimately provide the basis for a unified international standard for controllers’ general English skills. This will ensure that controllers can respond to a variety of nonroutine and emergency scenarios using English. Job proficiency should provide a basis for the standard and testing should be accomplished with respect to operational scenarios that a controller might encounter.

English courses that pilots and controllers attended in the past were primarily oriented toward development of conversation skills because of its importance in job performance. Although speaking and listening skills might be used most by controllers, reading and writing skills must also be developed in training, even if to a lesser degree. For language learning, all these skills reinforce each other. Some controllers and pilots, for example, learn general and technical vocabularies best with visual reinforcement from reading and writing.

Another language training problem is attrition caused by lack of practice, which has its greatest influence on listening and speaking skills. Most people who have studied a foreign language are aware of how quickly skills are lost if not used regularly. The English training program in countries where English use is limited will need to include mechanisms such as regular testing to identify skill attrition, with maintenance and refresher programs to counteract it. The value of costly training is lost when language skills atrophy and the training system does not respond by restoring proficiencies.

Examples from Russia show that the English problem is not easy to solve, but it is solvable. A comprehensive and systematic approach will provide the basis for a program that can be easily managed and evaluated for cost-effectiveness. Even the best-managed training will not eliminate inherent ambiguities in language, and will not compensate for poor discipline, fatigue and other problems in the workplace. But training will improve the ability of air traffic controllers to perform their jobs and greatly reduce the risk that controllers and pilots will communicate with, but not understand, one another.

Conclusion

Like the controllers and pilots who use English language for ATC communications, the aviation industry needs to be more aware of language issues so that it can design training systems to produce and maintain the necessary language skills. This will ensure that English training will be through and systematic as the other training that they receive, and that continued international use of English for-pilot-controller communications will support, rather than undermine, the safety of flight.