ATCO Language Skills

ATCO Language Skills


Many of the world’s air traffic controllers (ATCOs) must have the latest specified level of proficiency in the English language to safely accomplish their duties. Therefore, the staff of air navigation service providers (ANSPs) should be provided with courses focused on language instead of procedures and should include phraseology and the use of plain English.

Language performance requirements (LPRs) can include:

  • The ability to produce intelligible messages in unusual situations;
  • The ability to communicate using plain language in English and in other official national languages even under stress;
  • Understanding and making appropriate responses to pilot messages (spoken and written);
  • Adhering to International Civil Aviation Organisation (ICAO) phraseology; and,
  • Resolving misunderstanding in communication (e.g., by understanding cultural differences).

The English language proficiency of student air traffic controllers should be at an agreed minimum level prior to their employment in an international environment. This will allow them to carry out their assigned tasks ensuring the safety and expeditious handling of the affected air traffic.

Regional and national aviation authorities (NAAs) are the arbiters of exactly how to implement English proficiency for their ATCOs and ANSPs. They also must report to ICAO any differences between their practices and the international standards and recommended practices, and disclose in their Aeronautical Information Publication the radiotelephony languages that pilots from other countries will encounter at their aerodromes.

With the same rationale that English has been designated the default language for international pilots whose first language is not English, regulators and ANSPs also must make provisions for ATCOs to decide when safe communication dictates that they speak an official language of their country according to the needs, preferences and circumstances of pilots in their airspace.

Issue Background

This section briefly summarises steps since the late 1990s that have shaped LPRs for ATCOs at the global level and within the European Union (EU), according to ICAO and the European Union Aviation Safety Agency (EASA). The EU offers an example for regions and NAAs of how to reach consensus on controversial related issues and how to implement long-term solutions. At the global level:

  • The decision to address language proficiency–related threats to safety involving pilots and ATCOs was made in September 1998 as a direct response to an accident that involved 349 fatalities. The initiative also considered previous fatal accidents in which the lack of proficiency in English was a causal factor.
  • Between 1998 and 2008, the Air Navigation Commission developed new language-related provisions for four ICAO annexes.
  • States were required in November 2003 to make available proficient English-speaking ATCOs at all air traffic control (ATC) ground stations serving designated airports and routes used by international air services.
  • In 2007, ICAO urged those contracting states “not in a position to comply with the language proficiency requirements by the applicability date” to post their language proficiency implementation plans including their interim measures to mitigate risk.
  • Within three years after the 5 March 2008 applicability date, pilots and ATCOs in defined international operations were required to speak and understand English as an international language for radiotelephony communications. Each person’s ability had to be demonstrated according to ICAO’s new LPR holistic descriptors and its six-level language proficiency rating scale (i.e., passing the corresponding tests at Level 4 or above).
  • As cited by documents in this article and other SKYbrary articles, efforts to increase LPR compliance by states and to publish the latest state differences have continued from this formative period until 2020.
  • NAAs are responsible for the oversight of language proficiency assessments when issuing ATCO licenses or rendering valid licenses issued in other states.
  • ICAO also has urged CAAs to collect and analyse language test/assessment results and to analyse their safety occurrence reporting system, and all other other safety data, to detect and resolve cases of language proficiency becoming a causal factor.

International Expectations of ATCO Capabilities

In October 2013, ICAO reiterated the purpose of ATCO LPRs in Resolution A38/8 —“Proficiency in the English Language Used for Radiotelephony Communications.” The resolution explains: “To prevent accidents, ICAO introduced language provisions to ensure that [ATCOs] and pilots are proficient in conducting and comprehending radiotelephony communications in the English language, including requirements that the English language shall be available on request at all stations on the ground serving designated airports and routes used by international air services.”

The resolution also reinforced, and called on states to increase their efforts, in the following areas:

  • Reinforce the requirement to use ICAO standardised phraseology;
  • Emulate other states that “have made substantial efforts to comply” with the language proficiency requirements;
  • Assist states that encounter considerable difficulties in implementing the LPRs, such as their language training and testing capabilities;
  • Immediately notify ICAO whenever a state “finds it impracticable to comply in all respects with any international standard or procedure.”;
  • Disclose — by endorsement text printed on or attached to the ATCO/pilot licence — any failure of the licence holder to satisfy the LPRs, and enforce the international standard so that “no personnel having certificates or licences so endorsed shall participate in international navigation, except with the permission of the state or states whose territory is entered.”

Final Decisions: English for European ATCOs

Two of the latest documents issued by EASA detail the final ATCO LPR decisions that now guide the European Union’s NAAs and ANSPs, and place these decisions into a 2020–2024 planning context.

Essentially, they explain what is now in place and further steps to be taken to improve the performance of ATCOs who are qualified to conduct their duties in English as needed, and those who are qualified to conducted their duties only in languages other than English — typically based on the demand at specific aerodromes and airspace.

The European Plan for Aviation Safety (EPAS 2020-2024), published in November 2019, highlights the status of ATCO and pilot LPRs and the focus of EASA’s latest planning:

  • “LPRs have now moved beyond implementation [envisioned in] Assembly Resolution A38/8, entering a phase of post implementation.”;
  • “Despite the successful establishment of national LPR systems, there remains insufficient awareness, particularly in the selection of suitable and appropriate testing tools that meet ICAO LPRs, which may result in safety risks.”;
  • “Raw safety data shows only a very low number of incidents related to a lack of language proficiency, whilst a significant number of incidents are related to a lack of situational awareness because the radio communications were only in the local language.”;
  • EASA currently is working to “increase safety by reducing the risk of ineffective communication or even miscommunication when pilots and/or controllers need to face an unexpected situation and to use plain language.”;
  • “EASA has initiated an analysis of the raw data to ensure that not only those incidents that are directly related to language proficiency are included, but also those that show the lack of language proficiency in the chain of events.”; and,
  • Another EASA aspiration is for “all relevant stakeholders and Member States to work together on the maintenance, monitoring and revision of LPRI; to promote the common understanding of LPRI as a safety issue, linked to human factors principles; share lessons learned; encourage progress and harmonisation and develop good practice document to cope with operational, safety and standardisation needs.”

EASA was able to declare launch of its “post-implementation” phase of ATCO LPR, as noted, because the agency had finalised the Easy Access Rules for Standardised European Rules of the Air (SERA) in December 2018. Revisions were subsequently made in December 2020, November 2021, March 2022, and February 2023

The most pertinent SERA regulation — SERA.14015, “Language to Be Used in Air-Ground Communication” — was the culmination of a multi-year consultation process with EU NAAs, ANSPs, ATCOs and other stakeholders.

The following abbreviated key provisions settled longstanding disagreements about ATCO LPRs or, by their absence, deferral of an open question until a later time:

  • “The air-ground radiotelephony communications shall be conducted in the English language or in the language normally used by the station on the ground;
  • “The English language shall be available, on request of any aircraft, at all stations on the ground serving designated aerodromes and routes used by international air services;
  • “Unless otherwise prescribed by the competent authority for specific cases, the English language shall be used for communications between the ATS unit and aircraft, at aerodromes with more than 50,000 international IFR movements per year;
  • “[European Union] member states, where at the date of entry into force of this regulation, the English language is not the only language used for communications between the [air traffic service] unit and aircraft at such aerodromes, may decide not to apply the requirement to use the English language and inform the [European] Commission accordingly;

“In that case, those member states shall, by 31 December 2017 at the latest, conduct a study on the possibility to require the use of the English language for communications between the ATS unit and aircraft at those aerodromes for reasons of safety, so as to avoid incursions of aircraft on an occupied runway or other safety risks, while taking into account the applicable provisions of [European] Union and national law on the use of languages; [and,]

  • “The languages available at a given station on the ground shall form part of the [state’s] Aeronautical Information Publication and other published aeronautical information concerning such facilities.”

Beyond these provisions applicable to all NAAs and ANSPs, SERA.14015 recognises that some NAAs and ANSPs may want to modify ATCOs’ use of English language at specific aerodromes with more than 50,000 international IFR movements per year. If suitable justification is provided, EASA can accept deviations “for specific cases, based on an individual assessment of the local arrangements. In any case, deviation from the requirement should be limited to exceptional cases and should be accompanied with a safety assessment.”

The independent assessment of the proposed deviation’s safety impact requires consulting any available accident and incident investigation reports (at least at the EU level) in which ATCOs’ use of any language has been identified as an accident’s contributing factor.

The NAA also is expected to document “the proportion of pilots frequenting that airport, with English language proficiency endorsement [and] the proportion of pilots frequenting that airport, lacking language proficiency endorsement in the alternative language to be used.”

Through SERA’s provisions, EASA also encourages NAAs/ANSPs to consider requiring ATCOs’ use of the English language at aerodromes with less than 50,000 international IFR movements per year “based on local needs, such as seasonally high levels of international air traffic.”




Further Reading

  • Aviation English Language Test Service (AELTS), an ICAO website launched in 2011 and upgraded in July 2013 (Aviation English Language Test Service (AELTS) website.
  • “Implementation and Maintenance Recommended Checklist,” ICAO Language Proficiency Requirements, last updated on March 13, 2013.
  • “Guidelines for Aviation English Training Programmes,” ICAO Circular 323. These guidelines are based on work by the board and the members of the International Civil Aviation English Association (ICAEA).
  • For more information on the ICAO language proficiency requirements, consult Implementation of Language Proficiency Requirements on the ICAO website.

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