ENR 1.7 Altimeter Setting Procedures

03-DEC-2020

AIP Belgium and Luxembourg ENR 1.7-1 03-DEC-2020

1 GENERAL

The altimeter setting procedures in use generally conform to Part III of ICAO Doc 8168, Volume I.

1.1 Transition Altitude A common transition altitude of 4500FT is applicable in Brussels FIR.

1.2 Transition Layer (MIL only) The transition layer is the airspace between the transition altitude and the transition level. To ensure minimum standard radar separation between uncontrolled flights at or below 4500FT and controlled flights above the transition altitude, a transition layer of minimum 1000ft and maximum 1499FT will be taken into account to determine the transition level. Within the transition layer no minimum vertical radar separation with uncontrolled flights is provided.

1.3 Transition Level (MIL only) The transition level is the lowest flight level available for use above the transition altitude. The following parameters are used to calculate the transition level: • Transition altitude (TA): 4500FT; • Transition layer (Tlay): 1000FT; • Standard QNH: 1013.2HPA; • FT / HPA: 26.7; • Transition level (TRL); • Regional QNH (Reg QNH). TRL = [TA + Tlay + ((1013.2 - Reg QNH) x 26.7)] / 100 and rounded up to the first VFR or IFR flight level (whichever comes first). The calculation has to be correct to 0.0001 before rounding up to FL. This formula results in the value of the transition level in relation to the regional QNH taking into account a transition layer of minimum 1000ft and maximum 1499FT. This formula is primarily intended for precise calculations to be used in systems. A quick reference table is published below.

Regional QNH Transition Level 921 - 938 80 939 - 957 75 958 - 975 70 976 - 994 65 995 - 1013 60 1014 - 1031 55 1032 - 1050 50 1051 - 1069 45 1070 40

Corresponding Flight Level for a specific QNH value QNH 950 - 954.9 955 - 974.9 975 - 989.9 990 - 1009.9 1010 - 1024.9 1025 - 1044.9 1045 - 1055 ALT 500 25 20 15 10 5 0 -5 1000 30 25 20 15 10 5 0 1500 35 30 25 20 15 10 5 2000 40 35 30 25 20 15 10 2500 45 40 35 30 25 20 15 3000 50 45 40 35 30 25 20 3500 55 50 45 40 35 30 25 4000 60 55 50 45 40 35 30 4500 65 60 55 50 45 40 35 5000 70 65 60 55 50 45 40 5500 75 70 65 60 55 50 45

ENR 1.7-2 AIP Belgium and Luxembourg 03-DEC-2020

Corresponding Flight Level for a specific QNH value QNH 950 - 954.9 955 - 974.9 975 - 989.9 990 - 1009.9 1010 - 1024.9 1025 - 1044.9 1045 - 1055 ALT 6000 80 75 70 65 60 55 50 6500 85 80 75 70 65 60 55 7000 90 85 80 75 70 65 60 7500 95 90 85 80 75 70 65 8000 100 95 90 85 80 75 70 8500 105 100 95 90 85 80 75 9000 110 105 100 95 90 85 80 9500 115 110 105 100 95 90 85 10000 120 115 110 105 100 95 90

Note: An aerodrome QNH setting is a setting of which the source is located at or less than 5NM from the landing threshold.

2 PROCEDURES

2.1 Take-off and Climb A QNH altimeter setting is made available to aircraft in taxi clearance prior to take-off. Vertical positioning of aircraft during climb is expressed in terms of altitude until reaching the transition altitude above which vertical positioning is expressed in terms of flight level.

2.2 Approach and Landing

2.2.1 General A QNH altimeter setting and the transition level are made available in approach clearance and in clearance to enter the traffic circuit. Vertical positioning of aircraft during approach is controlled by reference to flight levels until reaching the transition level below which vertical positioning is controlled by reference to altitude. When flying outside controlled airspace at or below 4500FT AMSL, the altimeter should be set to the QNH of the aerodrome of destination as soon as entering the controlled airspace associated with it (TMA or CTR as the case may be). A QFE altimeter setting is only given on request and shall only be used for terrain clearance during final approach. The reference datum of the QFE altimeter setting is either: a. the threshold elevation: • for instrument runways (SRA or NDB approaches), if the threshold elevation is 7FT or more below the aerodrome elevation; • for precision approach runways (ILS); b. the aerodrome elevation.

2.2.2 Missed Approach Procedure for Military Pilots In the event of a missed approach, pilots shall use the QNH unless otherwise instructed by the control tower. If the missed approach procedure requires a climb above the transition altitude, pilots shall follow the relevant altimeter setting procedures given in § 1.3 above.

Note 1: Military pilots shall comply with the civilian instructions when flying within airspace controlled by civil authorities.

Note 2: An aerodrome QNH setting is a setting of which the source is located at or less than 5NM from the landing threshold.

2.3 En-route The cruising level at which a flight or a portion of a flight is to be conducted shall be expressed in terms of flight level when operated above the transition altitude. When flying in a controlled airspace associated with an aerodrome (TMA or CTR) at or below the transition altitude, the aerodrome QNH value given by the relevant control unit shall be used for the altimeter setting. When flying outside controlled airspace at or below 4500FT AMSL, the altimeter shall be set to the regional QNH given on pilot's request by Brussels FIC, Steenokkerzeel ATCC or by any ATC unit. The regional QNH is the lowest of the QNH values for the following stations: EBAW, EBBE, EBBR, EBCI, EBCV, EBFS, EBBL, EBFN, EBLG, ELLX, EBOS, EBSH and EBSP. VFR flights conducted at or below 3000FT AGL do not have to maintain a semi-circular cruising level and consequently are not compelled to use any particular altimeter setting. However, they are advised:

AIP Belgium and Luxembourg ENR 1.7-3 02-JAN-2020

• to take into consideration, for terrain and obstacle clearance purpose, either the regional QNH or the QNH value relevant to the area overflown (EBBR, ELLX, EBOS and EBSP) obtainable from Brussels FIC or Steenokkerzeel ATCC; • to take note that high speed low level military flights, having a flight visibility less than 5KM, are mandatory conducted under IFR and are therefore maintaining semi-circular IFR cruising altitudes based on the regional QNH.

3 TABLE OF CRUISING LEVELS

Magnetic track From 000 degrees to 179 degrees From 180 degrees to 359 degrees IFR flights VFR flights IFR flights VFR flights ALT ALT ALT ALT FL FL FL FL M FT M FT M FT M FT 10 300 1000 - - - 20 600 2000 - - - 30 900 3000 35 1050 3500 40 1200 4000 45 1350 4500 50 1500 5000 55 1700 5500 60 65 70 75 2300 7500 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 430 450 470 490 510 etc. etc.

ENR 1.7-4 AIP Belgium and Luxembourg 02-JAN-2020

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