Category Archives: General Aviation

Limitations and Dangers of the use of the English Language in Aviation Communications

Limitations and Dangers of the use of the English Language in Aviation Communications

AVIA 300 Aviation Safety – Week Seven

John Kirk


This paper is an overview of the limitations and dangers of the use of the English language in aviation communications.  Although the internationally agreed language in the air has been English since 1951, there was little research into the safety implications of this policy. Later, after too many examples of accidents where language difficulties were factors, research took place. The major results of that research are examined. Examples of aircraft accidents where language difficulties were a factor are examined. Some examples of regional dialectic differences are highlighted. Finally conclusions and recommendations are listed.


The KLM/ Pan Am disaster at Tenerife airport (Los Rodeos) on March 27th 1977 was the worst accident in aviation history in terms of loss of life. A major contributory factor was the failure in communication using the English language. The KLM aircraft had taken off without take-off clearance, in the absolute conviction that this clearance had been obtained, which was the result of a misunderstanding between the tower and the KLM aircraft.

This misunderstanding had arisen from the mutual use of usual terminology, which gave rise to misinterpretation. In combination with a number of other coinciding circumstances, the premature take-off of the KLM aircraft resulted in a collision with the Pan Am aircraft, because the latter was still on the runway since it had missed the correct intersection.

International Agreement

One of the outcomes based on this and many other accidents and incidents was the introduction of Language Proficiency Requirements (LPR) by the International Civil Aviation Organization (ICAO) in 2004. ICAO grades English language performance on a scale from 6 (highest) to 1 (lowest):

Level 6:


Level 5:


Level 4:


Level 3:


Level 2:


Level 1:


Formal evaluation of language proficiency was required as of March 2008, but ICAO effectively extended the deadline to 5th March 2011. In the USA the Code of Federal Aviation Title 14 (CFR) Part 61 requires that pilots must be able to read, speak, write and understand the English language. This proficiency is recorded on a pilot’s license. The current FAA standards for English language proficiency are laid out in Advisory Circular AC 60-28, English Language Skill Standards reproduced at Appendix 2.

Testing Standards

Whilst the ICAO recommendations determines the standards to be achieved, there is little information available on the reliability and accuracy of testing methods. A survey of aviation English TESTS Alderson, (2010) states, inter alia, “We conclude that we can have little confidence in the meaningfulness, reliability, and validity of several of the aviation language tests currently available for licensure.” (P. 1) This raises considerable concern, as the lack of creditable standards for testing creates a shortfall in the intention in the ICAO document. See Appendix 1 for the standards to which testing should be directed.

Even native English speaking aviators and air traffic controllers must pass knowledge tests which include standard phraseology which must be included in their initial training. In the USA, check airmen are required to certify English proficiency per the Practical Test Standards (FAA). If there is any doubt, a candidate must be referred to an aviation safety inspector (ASI) at the local FAA Flight Standards District Office. In the United Kingdom, a signatory to the Joint Airworthiness Agreement, a similar requirement has been established with the major difference that there are two levels of testing, formal and informal. English Language Schools accredited to the English Council are nominated for formal examination for levels 5 and below, and UK CAA examiners and some others are accepted for level 6.

Specific Example of Dialectic and Foreign Speaking Difficulties

Mention has already been made of the Tenerif accident as perhaps one of the best examples of a non-native English speaker’s difficulty. The phrase “We are now at takeoff,” is the key to understanding the difficulties. In the pilot’s native Dutch, the present progressive tense of a verb is expressed by the word “at” in English plus the infinitive of the verb, “takeoff.” The obvious interpretations of that phrase are:

  1. “We are holding at the takeoff position,” (which is the meaning the Spanish speaking air traffic controller assumed,)
  2. “We are in the act of taking off,” i.e. actually moving.

It is the second meaning that the Dutch pilot assumed the controller understood. The ICAO recommendations address this specifically where level 4 proficiency assumes, “Basic grammatical structures and sentence patters are used creatively and are usually well controlled. Errors may occur, particularly in unusual or unexpected circumstances, but rarely interfere with meaning.” Clearly, a fuller understanding of English grammar, as opposed to word-for-word translation of another native language, is key to success as in this example.

Second Example, voice warning systems

On November 13, 1993, a McDonnell Douglas MD-82 jet crashed in Urumqi, China, while it was approaching to land, killing 12 and injuring 24. Heard on the Cockpit Voice Recorder (CVR) was the last words of the native Chinese speaking pilot who said, “What does ‘Pull-up, pull-up” mean?” It is almost impossible to believe that there should be such lack of knowledge of audio warnings, especially to anyone outside of aviation.

Sources of Errors

The sources of communication error:

  1. Phonology – language sound patterns, prosody, e.g. speech rate, stress, intonation, pauses.
  2. Syntax – language word patterns, sentence structure.
  3. Semantics – language ‘meaning patterns’.
  4. Pragmatics – language in context, situational influences on meaning.

Considering numbers in voice communication conventional wisdom would say that as the digits are particularly standardized there should be little difficulty with regional language barriers. However, that assumption proves to be incorrect. Dr. Bürki-Cohen (Bürki-Cohen, 1995) researched the particulars of how complexity affects pilot recall. ATC normally are required to state digits individually, such as an altitude of 17,000 has to be stated as “one seven thousand.” ATC regulations allow controllers to add grouped digits after the individual digits were stated, i.e. “one seven thousand, seventeen thousand.” It was believed that this would aid retention and accuracy. However the research showed there was little difference with or without grouped digits added. Indeed, analysis showed an advantage of the restated format over the grouped format at higher complexity levels. It is axiomatic that increasingly complex verbal instructions carry a commensurate increase in the risk of misunderstanding.


If it is hoped to reduce the human factors accident rate more attention needs to be paid to language. The higher standard to which the international aviation community should aspire must constantly strive to ensure that the recommendations of ICAO in the area of English Language Proficiency should be achieved.


The following recommendations are suggested:

  1. Establish accredited schools for teaching English to all in aviation,
  2. Set clearer standards for testing and awarding all levels of proficiency,
  3. Research current “standard” phraseology, particularly differences between native English speaking nations, to harmonize those standards, reduce or eliminate ambiguity – particularly where cultural influences effect the use of language,
  4. Study pronunciation, and publish standard pronunciation for those words which exist in standard phraseology.


AC 60-28 CHG 1 Appendix 1


The following English language proficiency standards* must be met by the applicant and evaluated by the designated examiner or aviation safety inspector (ASI) when determining if the applicant meets the English language eligibility requirements of 14 CFR parts 61 and 63:

1.            PRONUNCIATION. Assumes that English is not the applicant’s first language and that the applicant has a dialect or accent that is intelligible to the aeronautical community. Pronunciation, stress, rhythm, and intonation are influenced by the applicant’s first language, but only sometimes interfere with ease of understanding.

2.            STRUCTURE. Relevant grammatical structures and sentence patterns are determined by language functions appropriate to the task. Basic grammatical structures and sentence patterns are used creatively and are usually well controlled by the applicant. Errors may occur, particularly in unusual or unexpected circumstances, but rarely interfere with meaning.

3.            VOCABULARY. The applicant’s vocabulary range and accuracy are usually sufficient to communicate effectively on common, concrete, and work-related topics. The applicant can often paraphrase successfully when lacking vocabulary in unusual or unexpected circumstances.

4.            FLUENCY. The applicant produces stretches of language at an appropriate tempo. There may be occasional loss of fluency on transition from rehearsed or formulaic speech to spontaneous interaction, but this does not prevent effective communication. The applicant can make limited use of discourse markers or connectors. Fillers are not distracting.

5.            COMPREHENSION. Comprehension by the applicant is mostly accurate on common, concrete, and work-related topics when the dialect, accent, or variety used is sufficiently intelligible. When the applicant is confronted with a linguistic or situational complication or an unexpected turn of events, comprehension may be slower or require clarification strategies.

6.            INTERACTIONS. Responses by the applicant are usually immediate, appropriate, and informative. The applicant initiates and maintains exchanges even when dealing with an unexpected turn of events. The applicant deals adequately with apparent misunderstandings by checking, confirming, or clarifying.

* Level 4 Rating Scale adopted from the ICAO Language Proficiency Rating Scale found in ICAO Document 9835 and the attachment in ICAO Annex 1.


Manual on the Implementation of the ICAO Language Proficiency Requirements – Doc 9835-AN/453

World Englishes, Vol. 23, No. 3, pp. 451–470, 2004. 0883–2919 Fatal miscommunication: English in aviation safety ATSUSHI TAJIMA

The challenge of regional accents for aviation English language proficiency standards: A study of difficulties in understanding in air traffic control–pilot communications. T. Tiewtrakul and S.R. Fletcher Ergonomics Vol. 53, No. 2, February 2010, 229–239

A survey of aviation English tests J. Charles Alderson, Language Testing 27(1) 51–72 2010 DOI: 10.1177/0265532209347196

An Analysis of Tower (Ground) Controller-Pilot Voice Communications. Final Report No. DOT-VNTSC-FAA-95-41

Bürki-Cohen, J. (1995). Say Again? How Complexity and Format of Air Traffic Control Instructions Affect Pilot Recall. In 40th Annual Air Traffic Control Association Proceedings, September 1995, 225-229.

Bürki-Cohen, J. (2003). Evidence for the Need of Realistic Radio Communications for Airline Pilot Simulator Training and Evaluation. In Proceedings of the International Conference Simulation of the Environment, Royal Aeronautical Society, 5-6 November, London, UK.

AC 60-28, English Language Skill Standards

Crew Resource Management            Date: 1/22/04            AC No: 120-51E TRAINING$FILE/AC120-51e.pdf




Do Pilots join associations? HAI, NEMSPA, AOPA


Here’s a question for all pilots, do you join associations, societies, or any aviation communities? A gut feeling tells me the answer is no! We live and work in a tiny little office, otherwise called a cockpit, for good reasons. There’s many a pilot who has said, either out loud or to himself, “I’m glad to get airborne to get away from the BS on the ground!”

“So what?”, I hear you cry. Well, there are some advantages to joining those organizations who represent us. Three in particular spring to mind, in no particular order:

Helicopter Association International

The first meeting of the founding members of this group took place on December 13th 1948. Yes, younger readers, there were helicopters way back then. Going through several name changes, the mission of the HAI has remained largely the same over more than 60 years. Their mission statement; “To provide its members with services that directly benefit their operations, and to advance the international helicopter community by providing programs that enhance safety, encourage professionalism and economic viability while promoting the unique contributions vertical flight offers society.”

You may join the HAI by clicking here.

National EMS Pilots Association

Whilst HAI serves the entire helicopter community world-wide, NEMSAP represents the EMS pilot in the USA. Much more specific and focused on issues that effect the American EMS pilot’s life. From personal experience, I know that NEMSPA has been very influential with those people who regulate us! It is clear that their efforts have prevented overbearing regulation, have created an influential voice for us all at Washington, DC, and are actively pursuing leading-edge research into issues that effect us all. Their mission statement; “We, the National EMS Pilots Association, will strive to help the Air Medical industry prosper safely and enhance the delivery of pre-hospital health care. We will provide the leadership necessary to establish standards of operational safety and a forum for the dissemination of knowledge. This organization will continue to be a major advocate for positive change for our industry.”

You may join by clicking here.

Aircraft Owners and Pilots Association

Incorporated on May 15th 1939, AOPA represents over 400,000 members. Their advocacy and campaigning efforts with the nation’s lawmakers and regulators have helped to prevent aviation hostile political people from closing us down, closing our airports, and from unfairly taxing us out of existence. The contribute greatly to aviation safety through their Air Safety Foundation, and rely on general aviation’s support through their Foundation.

AOPA’s mission statement; “We preserve the freedom to fly by…

advocating on behalf of our members,
educating pilots, nonpilots, and policy makers alike,
supporting activities that ensure the long-term health of General Aviation,
fighting to keep General Aviation accessible to all, and
securing sufficient resources to ensure our success.”

AOPA’s vision statement; “AOPA is the beacon for those who cherish the freedom to fly. It demonstrates what is possible when a determined organization listens to its members, collaborates with its colleagues, finds solutions with its partners in government, and focuses its resources—all to secure the future of General Aviation. AOPA’s success is proof that the public good can be served while individual freedoms are preserved.”

You may join by clicking here.

Bell Helicopter loses patent lawsuit | Airlines and Aviation | Dallas Business, Texas Bu…

Bell Helicopter loses patent lawsuit | Airlines and Aviation | Dallas Business, Texas Bu….

Rochester Wings 2012

May I recommend this year’s recurring annual event, Rochester Wings 2012.

The choice of propeller or turbine aircraft in short or long-range operations

This essay has application in the EMS world. Selection of a fixed wing aircraft for EMS operations depends on many factors. In the end, it is probably runway length that is the determining factor. Whilst the higher speed, range, and lower maintenance cost of a jet for EMS work might be an attraction, the loss of so many smaller regional airports would prohibit the carriage of many patients flown today. Read on….

Liberty U – AVIA 305 Week 4 Essay

The choice of propeller or turbine aircraft in short or long-range operations.


This essay will consider the factors in deciding which type of aircraft to use for short or long-range flights. Traditionally, propeller aircraft have been used for short-range flights and turbine engine aircraft for long-range flights.

Some of the factors include short field performance, range, and fuel used during a climb.

Short Field Performance – Climb Angle

Many of the regional airports have shorter runways than the major international airports. As stall speeds are lower for propeller driven aircraft, the speed at take off (Vr) is consequently lower. Therefore shorter take off runs are possible.

The maximum climb angle for a power producing aircraft is the stall speed, unlike thrust producing aircraft where maximum climb angle is at maximum lift/drag (L/D) ratio. For this reason airports with significant obstacles in the climb-out path are only suitable for propeller aircraft.

Comparison of power required curves.

See the fig. 8.1 below. Of particular interest is the shape of the two total power required curves (Pr). For the jet, the curve is relatively unaffected by increasing altitude, and yet the efficiency greatly increases. On the other hand, the power required curve shifts to the right for propeller driven aircraft with increasing altitude.. Indeed, it may be that Vmax may be reached before the maximum endurance speed is achieved in some aircraft. In short, propeller aircraft fly lower and slower than their jet counterparts.

Efficiency changes with altitude

Fuel consumption of power-producing aircraft is roughly proportional to the power produced, instead of the thrust produced. Range and endurance performance are functions of fuel consumption, and so the power required to fly the aircraft is of prime importance. There is little significant increase in efficiency for propeller driven aircraft with increasing altitude. Whilst endurance does increase with altitude, specific range remains little effected.

Climb efficiency

Consider the time and distance to height for either aircraft to climb to the most economical, or best range height. All other factors being ignored, the extra fuel burned to climb higher by the jet will make it less efficient over shorter range, where cruise may only be possible at height before it is time to descend for landing. As the propeller aircraft cruises more efficiently at lower altitude, less time and fuel will be consumed, and consequently more time at cruise altitude will be the norm.

Maintenance Cost Comparisons

R Babikian (2001) studied the costs and efficiencies of turboprop, regional jet, and turbine aircraft. This fascinating study revealed details of the average maintenance costs of each type, reproduced below. It has to be noted that the percentage maintenance cost for turboprop aircraft is 20.5% as compared to 15.8% for RJ’s and 7.5% for large jets. For this reason an increasing use of RJ’s has had a major impact on the cost efficiencies of short-range transportation.


Choice of aircraft for particular routes is a complex and involved process. Many factors are involved, some beyond the scope of this essay. However, the basic premise is that propeller aircraft are more cost effective over short range.