A transition level shall normally be specified for each airport by the state in which the airport is located. Where two or more closely spaced aerodromes are located so that coordinated procedures and a common transition altitude are required, a common transition level shall also be used at those aerodromes. The transition level may be located 300m (1000ft) above the transition altitude.
Note: Transition level is normally passed to aircraft in the approach and landing clearances.
Passing Through the Transition Layer
While passing through the transition layer, vertical position shall be expressed in terms of:
• flight levels when climbing; and
• altitude when descending.
System of Flight Levels
Semicircular Cruising Level System (ICAO)
Cruising Levels Applicable in RVSM Airspace