flight level (FL)

EASA defines “flight level (FL)” in one regulation. The wording below is reproduced verbatim from the EASA Easy Access Rules, with a link to the paragraph it comes from.

‘flight level (FL)’ means a surface of constant atmospheric pressure which is related to a specific pressure datum, 1013,2 hectopascals (hPa), and is separated from other such surfaces by specific pressure intervals;

Article 2 · Standardised European Rules of the Air (SERA) · Regulation (EU) No 923/2012 · Easy Access Rules, 26 Aug 2025 revision · Read Article 2

Also in the aviation glossary

Flight level (FL) FAA PHAK: A measure of altitude (in hundreds of feet) used by aircraft flying above 18,000 feet with the altimeter set at 29.92 "Hg.

Defined in the same article

accuracy
advisory airspace
advisory route
aerial work
aerobatic flight
aerodrome
aerodrome control service
aerodrome control tower

Ask Metis where flight level (FL) applies to you →

Metis opens with Avioverse in October 2026 · request early access.