ICAO Level 4
Operational English proficiency for pilots.
ICAO Level 4 (Operational) is the minimum English proficiency level required for pilots and air traffic controllers operating in international airspace. Level 4 is assessed against six criteria: pronunciation, structure, vocabulary, fluency, comprehension, and interactions.
To be rated Level 4, a pilot or ATC must demonstrate at least Level 4 in all six criteria — a Level 4 overall rating cannot be assigned if any single criterion is below Level 4. The overall rating is the lowest of the six criterion ratings.
Level 4 requires recertification every 3 years. Level 5 (Extended) requires recertification every 6 years. Level 6 (Expert) is essentially native-speaker proficiency and does not require recertification.
Levels 1–3 do not satisfy the ICAO requirement for international operations. Pilots at Level 3 must complete training to reach Level 4 before being authorized for international flights.