ATS.TR.140 Provision of altimeter setting information

(a)The appropriate air traffic services units shall at all times have available for transmission to aircraft in flight, on request, the information required to determine the lowest flight level which will ensure adequate terrain clearance on routes or on segment of routes for which this information is required.

(b)Flight information centres and area control centres shall have available for transmission to aircraft, on request, an appropriate number of QNH reports or forecast pressures for the flight information regions and control areas for which they are responsible, and for those adjacent.

(c)The flight crew shall be provided with the transition level in due time prior to reaching it during descent.

(d)Except when it is known that the aircraft has already received the information in a directed transmission, an QNH altimeter setting shall be included in:

(1)the descent clearance, when first cleared to an altitude below the transition level;

(2)approach clearances or clearances to enter the traffic circuit;

(3)taxi clearances for departing aircraft.

(e)An QFE altimeter setting as described in point ATS.TR.125(b) shall be provided to aircraft on request or on a regular basis in accordance with local arrangements.

(f)The appropriate air traffic services units shall round down the altimeter settings provided to aircraft to the nearest lower whole hectopascal.