English Language Proficiency Requirements

English Language Proficiency Requirements


This article outlines standards and recommended practices, as of early 2021, for aircraft pilots and air traffic controllers to attain one of three recognised levels of English language proficiency (ELP). In many cases, specific language proficiency is required to comply with licence qualifications.

The article focuses on relevant International Civil Aviation Organisation (ICAO) standards and recommended practices and the European Union’s ELP adoption decisions. Standardisation of ELP requirements mitigates known risks of accidents in many types of flight operations, including business aviation and commercial air transportation between nations or regions.

Benefits from standard-setting include fully understood communications between pilots and controllers, despite distracting non-standard words and phrases. High-level proficiency also enhances situational awareness through controller interactions and monitoring of surrounding air traffic communications.


For 70 years, ICAO has analyzed risks involving linguistic issues, raised awareness of systemic risks and pursued mitigations. In 2011–2021, ICAO and other stakeholders began to refine first-generation ELP standards and recommended practices.

ICAO set its first deadline — March 2008 — for ICAO Member States, planning for ELP standards to take effect at Level 4, Level 5 or Level 6 for all pilots flying international routes and all air traffic controllers serving international airports and routes. States unable to meet the first deadline were granted time to implement the acceptable language proficiency levels by March 2011. By 2013, ICAO reported that some Member States had serious difficulty and called on other nations to assist them.

ELP involves both native and non-native English speakers. According to ICAO, the burden for improving this aspect of aeronautical communications should not be seen as falling solely upon non-native English speakers.

Its Manual on the Implementation of ICAO Language Proficiency Requirements (Doc 9835), states: “Native speakers of English, too, have a fundamentally important role to play in the international efforts to increase communication safety.”

The following bullet points list basic concepts and expectations from FCL.055 Language Proficiency, a source frequently referenced by ICAO, EU and UK CAA requirements:

  • Aeroplane, helicopter, powered-lift and airship pilots required to use the radio telephony shall not exercise the privileges of their licences and ratings unless they have a language proficiency endorsement on their licence in either English or the language used for radio communications involved in the flight. The endorsement shall indicate the language, the proficiency level and the validity date.
  • The applicant for a language proficiency endorsement shall demonstrate, in accordance with Appendix 2 … at least an operational level of language proficiency both in the use of phraseologies and plain language.
  • At the operational level, the applicant shall demonstrate the ability to:
    • Communicate effectively in voice-only and in face-to-face situations;
    • Communicate on common and work-related topics with accuracy and clarity;
    • Use appropriate communicative strategies to exchange messages and to recognise and resolve misunderstandings in a general or work-related context;
    • Handle successfully the linguistic challenges presented by a complication or unexpected turn of events which occurs within the context of a routine work situation or communicative task with which they are otherwise familiar; and,
    • Use a dialect or accent which is intelligible to the aeronautical community.
  • Intervals for reevaluation of a pilot’s language-proficiency license endorsement depends on the pilot’s date of endorsement for demonstrating Level 4 (Operational Level), Level 5 (Extended Level) or Level 6 (Expert Level) proficiency, as follows:
    • Four years, if the level demonstrated is operational level;
    • Six years, if the level demonstrated is extended level; and,
    • Formal evaluation is not required for applicants who demonstrate expert level (i.e., native and very proficient non-native speakers with a dialect or accent intelligible to the international aeronautical community).
  • Holders of an instrument rating, in addition to abilities noted, shall have demonstrated — by the competent authority’s method of assessment — their ability to use the English language at a level that allows them to:
    • Understand all the information relevant to the accomplishment of all phases of a flight, including flight preparation;
    • Use radiotelephony in all phases of flight, including emergency situations; and,
    • Communicate with other crew members during all phases of flight, including flight preparation.

International Standards

The current requirements for ELP license endorsement of operational personnel primarily are detailed in ICAO Annex 1 — Personnel Licensing and explained in Manual on the Implementation of ICAO Language Proficiency Requirements, ICAO Doc 9835 (see References).

Annex 1, 1.2.9, “Language Proficiency” (July 2018) includes the following selected facts about applicability of ELP to specific aviation professions:

  • “As of 3 November 2022, aeroplane, airship, helicopter and powered-lift pilots; aeroplane, airship, glider, rotorcraft, powered-lift or free balloon remote pilots; air traffic controllers; and aeronautical station operators shall demonstrate the ability to speak and understand the language used for radiotelephony communications to the level specified in the language proficiency requirements in [Appendix 1, Requirements for Proficiency in Languages Used for Radiotelephony Communications].
  • ”As of 3 November 2022, the language proficiency of aeroplane, airship, helicopter and powered-lift pilots; aeroplane, airship, glider, rotorcraft, powered-lift or free balloon remote pilots; air traffic controllers; and aeronautical station operators who demonstrate proficiency below the Expert Level (Level 6) shall be formally evaluated at intervals in accordance with an individual’s demonstrated proficiency level.
  • “Note: The provisions of 1.2.9 refer to Annex 10, Volume II, Chapter 5, whereby the language used for radiotelephony communications may be the language normally used by the station on the ground or English. In practice, therefore, there will be situations whereby flight crew members will only need to speak the language normally used by the station on the ground.”

ICAO Language Proficiency Rating Scale

Reassessment Procedures

As noted above, ICAO requires that language skills of pilots and controllers rated at Level 4 are reassessed every three years, Level 5 pilots and controllers - every six years, while at Level 6, no further assessment of English language skills is deemed necessary.

The Level 4 (operational) proficiency is considered as a minimum ‘stepping stone’ to higher levels. The main benefit of high international standards of aviation English is that communications between aircraft crew and controllers are fully understood, particularly when non-standard words and phrases are used. Also, improved language skills could help increasing the situational awareness of flight crews in relation to other aircraft, both in the air and on the ground.

Note: Commission Regulation (EU) 2015/340 states that the validity of the language proficiency endorsement for expert level (level six) is nine years from the date of assessment, for the English language. This provision is applicable for air traffic controllers in the EU member states.

Accidents and Incidents

The following events include "Language Clarity" as a contributory factor:

On 12 November 1996, an Ilyushin IL76TD and an opposite direction Boeing 747-100 collided head on at the same level in controlled airspace resulting in the destruction of both aircraft and the loss of 349 lives. The Investigation concluded that the IL76 had descended one thousand feet below its cleared level after its crew had interpreted ATC advice of opposite direction traffic one thousand feet below as the reason to remain at FL150 as re-clearance to descend to this lower level. Fifteen Safety Recommendations relating to English language proficiency, crew resource management, collision avoidance systems and ATC procedures were made.

On 5 April 2019, a Boeing 737-500 crew declared an emergency shortly after departing Madrid Barajas after problems maintaining normal lateral, vertical or airspeed control of their aircraft in IMC. After two failed attempts at ILS approaches in unexceptional weather conditions, the flight was successfully landed at a nearby military airbase. The Investigation found that a malfunction which probably prevented use of the Captain’s autopilot found before departure was not documented until after the flight but could not find a technical explanation for inability to control the aircraft manually given that dispatch without either autopilot working is permitted.

Whilst a light aircraft was lined up for departure, a vehicle made an incorrect assumption about the nature of an ambiguously-phrased ATC TWR instruction and proceeded to enter the same runway. There was no actual risk of conflict since, although LVP were still in force after earlier fog, the TWR controller was able to see the vehicle incursion and therefore withhold the imminent take off clearance. The subsequent Investigation noted that it was imperative that clearance read backs about which there is doubt are not made speculatively in the expectation that they will elicit confirmation or correction.

On 3 August 2017, a Boeing 737-900ER landing at Medan was in wing-to-wing collision as it touched down with an ATR 72-500 which had entered the same runway to depart at an intermediate point. Substantial damage was caused but both aircraft could be taxied clear. The Investigation concluded that the ATR 72 had entered the runway at an opposite direction without clearance after its incomplete readback had gone unchallenged by ATC. Controllers appeared not to have realised that a collision had occurred despite warnings of runway debris and the runway was not closed until other aircraft also reported debris.

On 21 September 2012, two aircraft came into conflict in Class 'A' airspace whilst under radar control at night and loss of separation was resolved by TCAS RA responses by both aircraft. Investigation found that one of the aircraft had passed a procedurally-documented clearance limit without ATC clearance or intervention and that situational awareness of its crew had been diminished by communications with the conflicting aircraft being conducted in Spanish rather than English. A Safety Recommendation on resolving the persistent problem of such language issues was made, noting that a similar recommendation had been made 11 years earlier.


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