Section 1, Chapter 1 - Altimeter Setting Procedures

Question 1

What are the altimeter setting procedures and transition levels in the Belfast TMA?

Answer 1

Key points of the altimeter setting procedures in the Belfast TMA:

• Transition Altitude: 6000 feet above mean sea level (a.m.s.l.) based on Aldergrove QNH.
• Lowest MSL/MCL: FL70, regardless of the Transition Level, due to human factors.
• QNE Usage: When extreme pressures prevent setting QNH/QFE on the altimeter subscale.
• Departure Clearances: Aldergrove ATC will not issue departure clearances below the Transition Altitude of 6000 feet within the TMA.
• ATS Route Traffic: Must adjust to an altitude before entering the Belfast TMA if below the Transition Altitude.

Table for Determining Transition Level and Minimum Stack Level:

hPa / Transition Level / Minimum Stack Level
* 1060-1050 / FL60 / FL70
* 1049-1032 / FL65 / FL70
* 1031-1014 / FL70 / FL70
* 1013-995 / FL75 / FL80
* 994-977 / FL80 / FL80
* 976-959 / FL85 / FL90
* 958-940 / FL90 / FL90

Question 2

What are the QFE threshold differentials for the runways in the Belfast TMA?

Answer 2

The QFE threshold differentials for the runways in the Belfast TMA are:

• Runway 25: Zero differential
• Runway 07: +2.3 hPa
• Runway 17: +2.3 hPa
• Runway 35: +0.4 hPa

Question 3

Which Altimeter Setting Region (ASR) does Belfast International Airport lie within?

Answer 3

Belfast International Airport lies within the Belfast Altimeter Setting Region (ASR).

Question 4

What are the altimeter setting requirements for locally based light aircraft and transit aircraft within the Aldergrove Control Zone/TMA and FIR?

Answer 4

The altimeter setting requirements are:

• Within the Aldergrove Control Zone/TMA: All aircraft must fly on the Aldergrove QNH/QFE as appropriate.
• Within the FIR: Aircraft may fly on the Aldergrove QNH or Belfast Regional pressure setting at the pilot’s discretion. The Belfast Regional pressure setting is only provided upon request.