Synopsis

The EUROCONTROL Safety Improvement Sub Group (SISG) is aware that when providing traffic information some air traffic controllers routinely use “relative vertical position” (e.g. “1000ft above/below”) as the ‘level’ reference for other aircraft rather than referring to the other aircraft’s actual or expected level (i.e. its flight level, or altitude/height in metres or feet) as described in ICAO PANS ATM. This practice has been adopted because pilots receiving PANS ATM compliant traffic information sometimes misinterpret the ‘level’ information as an instruction to climb/descend to the stated level rather than assimilate it as traffic information about another aircraft. This problem can be exacerbated on a busy frequency and the use of different languages, accents and dialects often compounds any difficulty.

ICAO Requirements & Guidance

ICAO PANS ATM 12.3.1.1 describes how the word ‘level’ should be used in the context of ATC Phraseology, namely:

“Circumstances: DESCRIPTION OF LEVELS (SUBSEQUENTLY REFERRED TO AS “(LEVEL)”)

Phraseologies: a) FLIGHT LEVEL (number); b) (number) METRES; or c) (number) FEET.”