Different types of communication errors occur between pilots and ATC. These communication errors include the absence of pilot feedback, readback or hearback error, and hearback type II error (Wu et al., 2019). The absence of pilot feedback involves a scenario where a pilot does not acknowledge the clearance and fails to understand the message correctly. In addition, readback or hearback error entails a system where both the pilot and the ATC fail to recognize and identify an incorrect clearance. The pilot might read back a clearance incorrectly, and the ATC overlooks the readback error. Also, hearback type II error involves a scenario where a pilot reads the clearance correctly, but the ATC fails to notice that the issued clearance was not the one that they had intended to receive. Besides, the error that occurs when the ATC does not see the statement of action given by pilots is problematic. Thus, communication between pilots and ATC in airlines must be taken seriously to reduce the error rate.
Similarly, certain human factors can lead to miscommunication between pilots and ATC in airlines. The human factors include absent-mindedness and slips, ambiguity, callsign confusion, code switching, emergencies, expectation, and homonyms, and homophony. The factors are discussed below
Absent-mindedness and Slips
Occasionally, pilots and controllers tend to become absent-minded. For example, a controller might find themselves assigning a similar level for the descent to arriving aircraft. However, there is a time when a controller might note conflicting traffic at the same level and proceed to assign an inbound plane rather than offering a level separation. These kinds of flips are linked to external distraction or internal preoccupation among ATC, leading to absent-minded errors (Wu et al., 2019). Highly professional or habitual activities characterize absent-minded mistakes. These errors do not necessarily mean that the controller is incompetent, but they occur due to misapplied competence. Experts and not amateurs often make the problems. Professional ATC has a higher probability of making absent-minded slips. When individuals specialize in a particular field, there is less demand to use their working memory to complete an activity successfully. Mainly, professionals automatically perform their duties at a subconscious level. Absent-minded errors in airlines might lead to catastrophic results.
Different aspects of verbal communication might result in ambiguity. Many aviation accidents have been linked to ambiguity (Wilson, 2016). An example of these accidents includes the 1992 Air Inter Flight 148 crash that occurred in France. The accident resulted in the death of 87 people. It was caused by the usage of less-than-optimum phraseology by ATC and pilots. The controllers and pilots had ambiguous intentions and expectations. Thus, the flight experienced a sudden workload which led to a crash. The workload is associated with an increase in imprecision and vagueness (Wilson, 2016). Pilots and controllers might be confused by jargon and acronyms such as vague vernacular. Vagueness is perceived as a social affectation and is considered a polite way to address superiors in the workplace. Vagueness affects the delivery of information among ATC, which reduces situational awareness. Often, vagueness is experienced among amateur controllers, and it vanishes as they gain more experience.
In addition, ambiguous words such as pronouns and indefinite nouns can confuse pilot and ATC. For instance, the use of words with uncertain reference led to the Florida Everglades crash in 1972. ATC and pilots might have varying interpretations of words and procedures due to a lack of definition (Wu et al., 2019). In 1974, a Boeing crashed into a mountain in Washington. The crash was caused by a misunderstanding of words between controllers and pilots (National Aeronautics and Space Administration, 2018). The pilot had been cleared for the final approach while the controller had him for a VOR approach. He understood that there was no terrain above the altitude of 1800 feet. On the other hand, the controller understood that he had cleared the aircraft to fall away without interfering with other traffic, and the pilot had to control the plane to ensure that he avoided all terrains. There was a misunderstanding regarding the responsibilities of both pilots and controllers such that they all made their own interpretations. The ambiguity can result in miscommunication due to misunderstanding the type of radar service shared between the controllers and pilots.
Controllers can mistake one aircraft call sign for another, leading to crashes. Many incidents involve scenarios where pilots have accepted the wrong clearances resulting in fatal accidents (Wilson, 2016). The allocation of call signs is controlled through a central system in the U.K. and North America. Confidential Aviation Incident Reports show an example of aircraft that were operating under a similar frequency. In such an incident, controllers and pilots are prone to make mistakes that lead to losing lives. Registration callsigns consist of 26 possible last letters and ten numbers. They contain exact anagrams, final digits, parallel digits, and block digits which contribute to callsign confusion. Pilots tend to memorize their registration callsign during a flight. Hence there is a potential for confusion since these registration callsigns keep changing after every leg (Wilson, 2016). Registration callsigns for domestic flights have been reduced from four to two to ensure effective feedback in the aviation industry. Registration callsigns are crucial in developing situational awareness since pilots and ATC tend to differentiate aircraft-type or callsign association quickly.
Controllers and pilots can switch from one language to another when having a conversation. Habitual language change is characterized by inherent social and cognitive features (Pratama et al., 2020). These features are often poorly understood by the personnel in the aviation industry. The problem occurs when both the recipient and the sender have the same language but different dialects. Pilots or ATC might shift between the actual usage of a word clearly defined according to aviation equivalent (Pratama et al., 2020). In 1981, John Wayne Orange County Boeing 737 was involved in an accident due to the misinterpretation of the word hold. According to the aviation equivalence, the term ‘hold’ was used by pilots and controllers to mean ‘stop.’ The same remark might mean ‘to continue’ according to standard ordinary English. For example, the controllers might direct pilots to ‘hold their course’ during a flight, which means they should continue traveling and not stop. The use of the word ‘hold’ led to confusion that led to a crash that injured 34 people and destroyed the aircraft due to post-impact fire.
Complete language can occur among pilots and ATC who communicate in both English and French. These languages are used in the National Capital Region of Canada and Quebec. When a pilot initiates a French conversation, the ATC will respond in the same language (Pratama et al., 2020). Similarly, if the flight crew communicates in English, the ATC will be obliged to also speak in English. A misunderstanding or error might arise due to mixed languages as the international crew tends to converse in English. In contrast, the local crew uses the local language to communicate with ATC. Multiple parties tend to use similar radio frequencies to gain access to valuable party-line information that helps to improve situational awareness. Different users might not understand the party-line information if two other languages are used to communicate relevant information.
In-flight emergencies create tension which diminishes the language skills. Controllers must prioritize their tasks to ensure that they give the correct information (Molesworth & Estival, 2015). They should concentrate when delivering critical information. The ATC should provide slow and clear speech to ensure that pilots receive the correct information. ATC for whom English is the second language must concentrate during emergencies to avoid incorrect pronunciations. Distractions resulting from in-flight emergencies can cause slips during the communication between the ATC and pilots (Molesworth & Estival, 2015). Emergencies make it hard for controllers and pilots to enunciate certain words. Poor enunciation during a conversation makes the receiver doubt the message that has been communicated. Thus, the receiver may fail to acknowledging instructions or request the sender to repeat the message.
High workload or distraction can result in a change in expectations. Mainly, expectation errors among pilots and ATC are caused by information overload and fatigue (Wu et al., 2019). Noise interferes with the communication signals making pilots or controllers hear what they expect rather than what is said. Listeners misunderstand the intended message in case it differs from what they had anticipated. In 1997, an aircraft was directed to ascend to FL310. When the plane was traveling at FL260, the controller was interested in knowing the exact speed of the aircraft. The pilot responded that the aircraft was traveling at 315 knots. After receiving the readback, the controller directed the pilot to maintain the 280. The pilot misconstrued the message and responded to the controller to ensure that he traveled at 280 knots. The pilot started climbing to reach FL295. The controller got puzzled since he had cleared the pilot to fly at FL280. In this case, the controller did not indicate that he had set the airspeed rather than altitude (National Aeronautics and Space Administration, 2018). Due to the poor phraseologies of the controller, he issued incomplete information and did not monitor the pilot’s readback to detect that he had said “knots” rather than maintaining the flight level. The message was misunderstood due to variations in expectations.
Homonyms and Homophony
Homonyms and homophony entail a confusion-inducing phenomenon as a result of words or phrases that sound alike. The phenomenon can be demonstrated by a crash in Kuala Lumpur, which involved the Flying Tigers Boeing B747. The crash occurred due to misinterpretation of words with similar pronunciations such as ‘to, too, and two’ (Molesworth & Estival, 2015). The aircraft had poor visibility due to fog. The flight crew received a clearance to descend to two thousand seven feet. The controller had informed the flight crew about dropping to “two seven zero zero” feet. The pilot gave a readback and announced to the controller that he had received the intended message. The controller issued other messages which directed the pilot to descend to “two four zero zero” feet. The pilot misunderstood the message where he readjusted dropping to “four zero zero” feet. The controller did not analyze the readback to detect that the pilot had omitted the first number and descended to four hundred feet rather than two thousand four hundred feet. The flight killed four crew as it crashed on the runway. The accident could have been avoided if the controller had avoided using the words ‘to’ and ‘two’ when issuing the second clearance. In the aviation industry, this problem is avoided using different techniques such as pronouncing ‘to’ as ‘tah.’
Communication errors between air traffic controllers and pilots are the main factors contributing to various failures in the air traffic system. The flexibility of the air traffic system is determined by the effectiveness of voice communication between controllers and pilots. Incorrect decisions can be made in a scenario where ambiguous information is communicated. In most cases, pilots and controllers might fail to notice that they are experiencing a miscommunication problem. Individuals whose English is poor might take some words for granted or fail to understand them, leading to miscommunication. Specifically, human factors that cause miscommunication between air traffic controllers and pilots include absent-mindedness and slips, ambiguity, callsign confusion, code switching, emergencies, expectations, homonyms, and homophony. Implementation of advanced communication technology can improve communication in the air traffic system.
Molesworth, B. R. C., & Estival, D. (2015). Miscommunication in general aviation: The influence of external factors on communication errors. Safety Science, 73, 73–79. https://doi.org/10.1016/j.ssci.2014.11.004
National Aeronautics and Space Administration. (2018). ASRS Database Report Set. https://asrs.arc.nasa.gov/docs/rpsts/plt_ctlr.pdf
Pratama, M. D. Y., Yassi, A. H., & Machmoed, H. A. (2020). Code-switching applied by air traffic controller in air navigation services. IOP Conference Series: Earth and Environmental Science, 575, 012170. https://doi.org/10.1088/1755-1315/575/1/012170
Wilson, D. (2016, October 20). Failure to Communicate – Flight Safety Foundation. Flight Safety Foundation. https://flightsafety.org/asw-article/failure-to-communicate/
Wu, Q., Molesworth, B. R. C., & Estival, D. (2019). An Investigation into the Factors that Affect Miscommunication between Pilots and Air Traffic Controllers in Commercial Aviation. The International Journal of Aerospace Psychology, 29(1-2), 53–63. https://doi.org/10.1080/24721840.2019.1604138