All you need to know about ICAO Level IV…

Dear aviaexperts,

More than a decade has passed since the introduction of the ICAO language proficiency requirements to aviation personnel (March 5, 2008). However, questions asked by aviation specialists make us think that the term “language competence” still requires clarification.

Here are some of the remarks:



  • what triggered changes in international aviation legislation, get a historical background and understanding of the factors which led to  initiation of new international language requirements for aviation personnel;
  • the ICAO documents which state provisions related to the language field;
  • the difference between general English, aviation English, Radiotelephony and ICAO phraseology;
  • what the ICAO Scale is and what competencies it assesses;•what exactly ICAO level IV is, you will hear and be able to compare speech samples of aviation specialists at different levels;
  • … and get a Take Home Message

Over 800 people were killed in three major aviation accidents (ground collision, fuel starvation, and controlled flight into terrain). They seem to be different types of accidents, but investigation revealed one common factor contributing to each of the three crashes – lack of language proficiency which contributed to the development of the chain of events leading to disaster.

Concerns were raised again after 349 passengers and crew were killed in a mid-air collision in 1996, which was also caused by poor English. In addition, numerous incidents and cases of nearmiss due to language problems are reported each year, which has led to a review of aviation communication procedures and standards around the world and resulted in

the ICAO Assembly Resolution A32-16 for the Contracting States to undertake measures to ensure that ATC personnel and flight crew members involved in providing and performing flights in the airspace where the use of English is required have sufficient skills to conduct radiotelephone communications in English.

In March 2003, the Council adopted amendments to Annexes 1, 6, 10, 11, and the PANS-ATM relating to language proficiency in international civil aviation.

The SARPs relating to language use for aeronautical radiotelephony communications that were adopted by the ICAO Council in March 2003 are found in Annex 1; Annex 6, Parts I and III; Annex 10, Volume II and Annex 11 (see Appendix A).

The language-related SARPs can be broadly categorized into three types:

  • Annex 10 SARPs clarify which languages can be used for radiotelephony communications;
  • Annex 1 SARPs establish proficiency skill level requirements as a licensing prerequisite;
  • Annexes 6 and 11 provide for service provider and operator responsibility.

Other language-related information and guidance material are contained in the PANS-ATM (Doc 4444), Chapter 12, and in the Foreword to Doc 9432.

References in ICAO Annexes concerning language provisions

Table 1

Annex Reference Focus
1 1.2.9



Пункт, XIII

Appendix 1

Attachment A

Language proficiency.



Adding a language proficiency mark to the certificate.

License endorsement Requirements for proficiency in languages used for radiotelephony communications

ICAO Language Proficiency Rating Scale




Part I

Part III




Section II, п. 1.1.3

Operators’ responsibility.



Operators’ responsibility.




Volume II

5.1.1 and–

Radiotelephony discipline.



Using standardized phraseology and plain language.

Language to be used in aeronautical radiotelephony.

Pronunciation of numbers.

Transmitting technique.

11 2.29 Air traffic services providers’ responsibility.



Language to be used between ATC.

Below are extracts from Annex 1. Language proficiency:

1.2.9 Language proficiency Aeroplane, airship, helicopter and powered-lift pilots and those flight navigators who are required to use the radio telephone aboard an aircraft shall demonstrate the ability to speak and understand the language used for radiotelephony communications. Air traffic controllers and aeronautical station operators shall demonstrate the ability to speak and understand the language used for radiotelephony communications. Recommendation. Flight engineers, and glider and free balloon pilots should have the ability to speak and understand the language used for radiotelephony communications.  As of 5 March 2008, aeroplane, airship, helicopter and powered-lift 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.

Appendix 1

The ICAO language proficiency requirements include the holistic descriptors at Section 2 and the ICAO Operational Level (Level 4) of the ICAO Language Proficiency Rating Scale in Attachment A.The language proficiency requirements are applicable to the use of both phraseologies and plain language. To meet the language proficiency requirements contained in Chapter 1, Section 1.2.9, an applicant for a licence or a licence holder shall demonstrate, in a manner acceptable to the licensing authority, compliance with the holistic descriptors at Section 2 and with the ICAO Operational Level (Level 4) of the ICAO Language Proficiency Rating Scale in Attachment A.

Термин “Aviation English” covers a relatively broad area. It can refer to  language used by representatives of various professions, such as engineers, technicians, sales personnel, flight crews, etc., working in the aviation field, which itself includes such areas as aircraft manufacturing, aircraft operation, aircraft maintenance, air traffic management, flight organization, airfield operation, handling services and others.

The ICAO language proficiency requirements relate exclusively to the language of aviation radiotelephone communications, a subcategory of aviation language that covers a limited number of situations of the language used by two aviation professions – ATC controllers and flight crew members. It includes both standard ICAO phraseology and general English used in aviation context.

Standard ICAO phraseology is a minimal list of lexical and grammatical means used in radio communication. Standard ICAO phraseology is specified by ICAO Doc 4444 (volume II, Annex 10, Chapter 12). It comprises words and sample sentences specific for different procedures, their interpretation, pronunciation rules. The use of standard ICAO phraseology is also specified in ICAO Doc 9432.

Standard ICAO phraseology is characterized by:

  • Limited vocabulary (about 400 words).
  • Short sentences (articles, possessive and personal pronouns, auxiliary verbs, many prepositions are NOT used);
  • Imperative mood and Passive voice.

Here are the examples:

  • Cleared to land
  • Report when ready
  • Say rate of climb
  • Requesting low pass
  • Heading is good

Aviation specialists shall remember Phraseology Golden Rule: ONE WORD = ONE MEANING.


The ICAO documents (Annex 10, Chapter 5, paragraph instruct radio exchange participants to use standard phraseology in all cases it is assigned to. General English may be used when standard phraseology is not enough to convey the meaning of the message.


There are plenty of non-routine situations, when phraseology offers no typical phrases to communicate the meaning. This is when pilots and ATC controllers have to revert to general English. For example, on the line up position pilots notice a dog on the runway. They may call Control with the following phrase “Norton Tower, there is a dog on RWY 05L. Send somebody to catch it.”


General language in aeronautical radiotelephone communications refers to spontaneous, creative use of some natural language, which being subject to safety requirements shall be clear, direct, relevant, unambiguous and brief.

Schematically, the relationship between the language terms described in this section may look like this:



What skills does it assess?

The ICAO scale is a tool specifically worked out to assess the level of language proficiency. Using a metaphor, we can say that this is a kind of weight scale, which impartially shows the weight of the one who is being weighed. Probably, many of us have seen the scales which in addition to the total body weight shows the muscle weight, bone weight, body liquid, and other parameters..

The ICAO scale looks similar as it shows not only the general level of language proficiency, but also the level of individual parameters called skills or competencies.

There are six skills to be assessed. They define:

  • ability to pronounce words (pronunciation)
  • ability to build sentences (grammar structures)
  • ability to select words to express yourself (vocabulary)
  • ability to speak at a pace that is comfortable for perception (fluency)
  • ability to understand the meaning of something being spoken    (comprehension)
  • ability to respond adequately in various speech situations — to requests, instructions, suggestions, etc. (interaction)

A combination of these skills at appropriate level allows to ensure safety on the ground and in the air.


The scale is divided into six levels, where the first three levels describe language proficiency which is not enough to ensure safety. Level 4 is called the MINIMUM SAFE or Operational level, since it is the one that you can start working from (see the table below).
Table 2

Pronunciation Structures Vocabulary Fluency Comprehension Interaction
Professional grade
(Expert,— level 6)
Advanced level
(Extended – level 5)
Operating level(Operational – level 4) Minimum safe level of language proficiency
Level is lower than the worker(Pre-Operational – level 3) NOT QUALIFIED
Initial level(Elementary – level 2)
Level is lower than initial(Pre-Elementary –level 1)

Each skill at each level is described for raters and examiners to assess a candidate.

Below are frequently asked questions about the ICAO scale.

Question: Does the ICAO scale assess skills related to reading technical documentation and writing?

Answer: No. The scale is used for assessing speaking and listening skills.

Question: How difficult is level 4?

Answer: ICAO level 4 does not require high level of grammatical accuracy and native pronunciation. Grammar, vocabulary, and pronunciation are assessed in terms of their sufficiency to communicate the message.

Question: If one of the skills is rated at level 3, and all others at level 4, what is the rating result?

Answer: Often, aviation specialists think that they were rated lower than they performed. Perhaps most of their skills were actually at a higher level. However, the final rating is not the average or the sum of 6 competence ratings, but the lowest of the six. This approach is stipulated by the level 4 criteria defining the minimum of language proficiency for safe operations. Any of the six skills rated below level 4 indicates inadequate level of language proficiency. For example, a pilot who was rated 4 in all the skills except pronunciation may not be understood by ATC controllers, which can compromise flight safety. Thus, in order to be rated level 4, candidates shall demonstrate language proficiency not lower than level 4 across all six competences.

Question: How long does it take to learn a language from almost a scratch to the advanced level?

Answer: The ICAO Scale is not a scale of equal time periods; the time required to climb from one level to another will vary and depend on the trainee’s personal characteristics. In other words, it may take more time or training to move from level 2 to level 3 than it does to move from level 4 to level 5.

Question: Does the ICAO scale assess the use of standard ICAO phraseology?

Answer: ICAO proficiency rating scale clearly focuses on aviation radiotelephone communications, that is on the ability to use the language in a work-related context in unexpected turn of events. The key point is to assess a specialist’s competence beyond the standard, i.e. in situations where ICAO standard phrases are not enough.

Below are the descriptions of four skills from the ICAO scale, which correspond to the description of standard ICAO phraseology:
Table 3

Structure Vocabulary Comprehension Interaction
Shows only limited control of a few simple memorized grammatical structures and sentence patterns. Limited vocabulary range consisting only of isolated words and memorized phrases. Comprehension is limited to isolated, memorized phrases when they are carefully and slowly articulated. Interaction is limited to simple routine exchanges

If you look at the scale, you will see that these descriptions correspond to ICAO level 2; in other words, standard ICAO phraseology alone will not allow you to move above level 2.

This section gives the overview of ICAO level 4 with regard to all 6 skills

Table 4



Skill Description Example
Pronunciation Operational Level 4 is certainly not a perfect level of proficiency; Pronunciation, stress, rhythm and intonation are influenced by the first language or regional variation, but only sometimes interfere with ease of understanding. Operational Level 4 speakers demonstrate a marked accent, or localized regional variety of English. Occasionally, a proficient listener may have to pay close attention to understand or may have to clarify something from time to time.



There are several distinct national accents of English, such as American accent, French accent, Arabic accent, Chinese accent, and Slavic (Russian) accent. It should be remembered that  people of the same nationality speaking English will always understand each other. The reason is that their ear is tuned to the national accent of the country they live in. It can take months or years to tune in. It is important to polish your pronunciation to the level understandable to the international community.

1. Listen to a French aviation specialist who was assessed level 4 in all skills accept the pronunciation.



Often his pronunciation impedes understanding.

§ The cabin, uh, the cabin crew, uh, how/had(?) to deal with this passenger, maybe to uh, to keep it, uh, keep him quiet in a, on a seat uh (02:54 – 03:13)

§ Hm, yes, when I was air traffic controller in *** (airport) I have to uh, to *** some aircraft uh, with uh, uh very ill uh passengers like a heart break uh, *** aircraft the crew they have an answer.(03:21 – 03:51)

§ I have to, to call the, depends on the *** (the fire man or ?) the technician, the the people are working on the runway with a fire coat, or to try to catch the, the dog (03:57 – 04:17)

§ No, I don’t think it is a good idea because uh, uh if uh there is a gun onboard, uh, the air marshal uh, maybe wants uh use uh, use his gun, and uh, this uh, uh this is really uh, ***, it is very dangerous to have a gun onboard (06:49 – 07:23)

His native language often influences words stress, though it doesn’t interfere with ease of understanding:

§ photographer, mountains (01:48 – 01:59)

2. Listen to the speech samples where incorrect pronunciation distorts the meaning:

§ When I have free time I like sky and skiting (skiing)

§ May be the tag (tug) entered into the RWY without permission

Grammatical constructions Operational Level 4 speakers have good command of basic grammatical structures. They do not merely have a memorized set of words or phrases on which they rely but have sufficient command of basic grammar to create new meaning as appropriate. They demonstrate local errors and infrequent global errors and communication is effective overall. Level 4 speakers will not usually attempt complex structures, and when they do, quite a lot of errors would be expected resulting in less effective communication.значительного количества ошибок, снижающих эффективность коммуникации.

1. The following samples demonstrate local errors which do not interfere with understanding.

§I work as ATC about 26 years (Present Simple instead of Present Perfect)

§He never shout at cabin crew members (no third person singular)

§not bad paid job (adjective instead of adverb)

§I shall pick up his (wrong word order)

§different uh country use aviation in the world (singular instead of plural)

2. Next example contains global mistakes which distort the meaning:

§Some time ago the aircraft had lights…at…where I work… my seat…is.. was lightning very bad and my eyes in 1-2 hours look badly, but now, 2 years ago these lights was changed for new and now condition beginning better.

3.Listen to the speech samples where Russian candidates use Russian grammar structures to speak English:

Any Russian person speaking English will understand them. People of other nationalities could only guess the meaning.

§… because of every year aircraft in the sky became more and more.

§ The emergency equipment check co-pilot and flight §attendant.

Vocabulary An Operational Level 4 speaker will likely not have a well-developed sensitivity to register (see glossary on page (ix)). A speaker at this level will usually be able to manage communication on work-related topics, but may sometimes need clarification. When faced with a communication breakdown, an Operational Level 4 speaker can paraphrase and negotiate meaning so that the message is understood. The ability to paraphrase includes appropriate choices of simple vocabulary and considerate use of speech rate and pronunciation.

Listen to a speech sample:


He is familiar with typical work-related terms:

§appropriate services (04:31 — 05:05)

§facilities (09:54 — 09:56)

§Sometimes he is appropriate at using spoken English:

§to keep in my head (00:40 — 00:42)

However, in general, his vocabulary is limited, he often repeats the words he heard from his interlocutor. When he tries to express his own ideas, the word choice may often be inadequate.

§different homeworks (different jobs to do at home) (02:11 — 02:13)

Fluency Speech rate at this level may be slowed by the requirements of language processing, but remains fairly constant and does not negatively affect the speaker’s involvement in communication. The speaker 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. Can make limited use of discourse markers or connectors (at first, then, finally), fillers (let me think,  in my opinion), linkers (and, but, so).

1.Listen to a Chinese speaker whose fluency is below level 4.


The candidate is trying to speak at length, but pausing caused by word processing interferes with communication ease.

§functions as a controller (00:57 — 01:45)

§reduced vertical separation minima (02:03 — 02:37)

§the quality of the simulator (04:33 — 04:54)

§the picture of meteorological conditions (14:55 — 15:45)

§the story (16:59 — 19:14)

2.Listen to a Russian speaker, whose long pauses and time required to formulate sentences impede understanding.

Complrehension Comprehension is mostly accurate on common, concrete and work-related topics when the accent or variety used is sufficiently intelligible for an international community of users. When the speaker is confronted with a linguistic or situational complication or an unexpected turn of events, comprehension may be slower or require clarification strategies (Could you repeat that, please? What do you mean?)

Often, candidates pick up one word or phrase from the question asked and start answering a completely different question. Listen to two samples when the candidates misinterpret the examiner’s question:


In the first sample, the question was about fire-fighting equipment, whereas the candidate started talking about the case of a fire on board.

In the second sample, the question was asked about what the candidate would like to achieve at the end of his aviation career. In response, he starts speaking about his career background.

Interaction Responses are usually immediate, appropriate and informative. Initiates and maintains exchanges even when dealing with an unexpected turn of events. At Operational Level 4, it is acceptable that comprehension is not perfect 100 per cent of the time when dealing with unexpected situations, but Level 4 speakers need to be skilled at checking, seeking confirmation, or clarifying a situation or communication. Listen to the speech samples which demonstrate adequate use of clarification strategies allowing to resolve misunderstanding.



For more speech samples and their ratings, use the following links

ICAO level 3

ICAO level 4

ICAO level 5

ICAO level 6

For more speech samples and their ratings, use the following links



  1. Remember to use Standard ICAO phraseology disregarding how perfect your general English is. In any routine situation it makes communication safe and adequate.
  2. Remember: as long as you are pursuing your professional career, the English language is part of your qualification, like, for example, piloting or sequencing the aircraft. You simply can’t take vacation from endorsement to endorsement.
  3. Remember, that language endorsements can become a routine satiation, if you try to maintain your language proficiency in-between.
  4. Remember, any test is stressful. Being stressed people can still adequately use knowledge and skills when they are almost automatic.
  5. Remember, that stress “eats up” competences. Level 5 candidates in a stressful situation usually demonstrate level 4.
  6. Remember, that unlike many other disciplines, it is impossible to get ready for an English test overnight. What is possible overnight is to learn the test format, type of test tasks, their duration, a list of possible topics.
  7. Remember, approved language proficiency tests are almost the same in complexity. The difference may be in test tasks. This is why before taking a test, make sure you get familiar with the test format.