ATS.TR.125 Expression of vertical position of aircraft

(a)For flights in areas where a transition altitude is established, the vertical position of the aircraft shall, except as provided for in point (b), be expressed in terms of altitudes at or below the transition altitude and in terms of flight levels at or above the transition level. While passing through the transition layer, the vertical position shall be expressed in terms of flight levels when climbing and in terms of altitudes when descending.

(b)When an aircraft which has been given clearance to land, or when at AFIS aerodromes an aircraft which has been informed that the runway is available for landing, is completing its approach using atmospheric pressure at aerodrome elevation (QFE), the vertical position of the aircraft shall be expressed in terms of height above aerodrome elevation during that portion of its flight for which QFE may be used, except that it shall be expressed in terms of height above runway threshold elevation:

(1)for instrument runways if the threshold is 2 m (7 ft) or more below the aerodrome elevation;

(2)for precision approach runways.