Definition

Cleared Flight Level (CFL). The flight level at or to which an aircraft is authorised to proceed under conditions specified by an ATC unit.

Source: EUROCONTROL EATM Glossary of Terms

Decription

The cleared flight level (CFL) is the flight level that an air traffic controller has cleared a controlled flight to maintan or climb/descend to.

Note: CFL is part of the broader term "cleared level" which encompasses "cleared altitude" and "cleared height" as well. This article focuses on the representation and use of the cleared level in automated ATM systems which are the primary tools of approach and area controlers. Therefore, the more specific term (CFL) is used instead of the broader one (cleared level).