2.1.1   System of flight levels

1. Flight level zero is located at the atmospheric pressure level of 1013.2 hPa. Consecutive flight levels are separated by a pressure interval corresponding to at least 1000 feet (3050 m) in the Standard Atmosphere.
2. Flight levels are numbered according to the following table, which indicates the corresponding height in the Standard Atmosphere in feet and the approximate equivalent height in meters.

2.1.2   Transition altitude

The transition altitude specified for Budapest FIR is 9000 feet.

2.1.3   Transition level

The transition level will be determined by the appropriate ATC unit so as to give a transition layer of at least 1000 feet (305 m) vertical separation above the transition altitude.

For determination of current transition level the following table is used.

The transition level at Budapest Liszt Ferenc International Airport is transmitted normally in ATIS broadcast, or is involved in the clearances as appropriate.

2.1.4   Transition from flights to altitudes and vice versa

The vertical position of aircraft when at or below the transition altitude shall be expressed in terms of altitude, whereas such position at or above the transition level shall be expressed in terms of flight levels. While passing through the transition layer, vertical position shall be expressed in terms of flight levels in climb and in terms of altitude when descending.

2.3.1   Vertical position

2.3.2   Terrain clearance

1. QNH altimeter setting and temperature in-formation are included in routine reports for use in determining adequate terrain clearance. These data are transmitted normally in ATIS and VOLMET broadcasts and are also available on request from ATIS units.
2. Normally the QNH value determined for Budapest Liszt Ferenc International Airport is used as “regional QNH” within Budapest FIR.
3. ATC units determine the lowest usable flight levels for the whole part of the control area for which they are responsible, and use it when assigning flight levels and pass it to pilots on request.

   Note: The objectives of the air traffic control services as prescribed in Annex 11 do not include prevention of collision with terrain. The procedures prescribed above do not therefore relive the pilots' responsibility of ensuring that any clearances issued by ATC units are safe in this respect, except when an IFR flight is vectored by radar.

4. When vectoring an IFR flight, the radar controller shall ensure the adequate terrain clearance at all times until the aircraft reaches the point where the pilot will resume own navigation.