ENR 1.7  ALTIMETER SETTING PROCEDURES

1.  Introduction

1.1 The following altimeter setting procedures describe the method for providing adequate vertical separation between aircraft and adequate terrain clearance during all phases of flight.
1.2  QNH and QFE values are given in whole hectopascal or inch of mercury, but they will be provided in tenths on request for landing.

2.  Basic altimeter setting procedures

2.1  General
2.1.1 The transition altitude for Bangkok FIR is 11000 ft.
2.1.2 The transition level for Bangkok FIR is flight level 130 (FL130).
2.1.3 The transition layer is located between the transition altitude and the transition level.
2.1.4 The vertical position of aircraft operating at or below the transition altitude shall be expressed in terms of altitudes, which are determined from an altimeter set to sea level pressure (QNH).

Note: This does not preclude a pilot using a QFE setting for terrain clearance purposes during the final approach to the runway.

2.1.5 The vertical position at or above the transition level shall be expressed in terms of flight levels, which are surfaces of constant atmospheric pressure based on an altimeter setting of 1013.2 hPa or 29.92 inHg
2.1.6 While passing through the transition layer, vertical position shall be expressed in terms of:
2.1.6.1 flight levels when climbing; and
2.1.6.2 altitudes when descending.
2.1.7 Cruising within the transition layer is not permitted unless specifically cleared by the ATS unit providing control services for that portion of airspace.
2.1.8 While operating in the transition layer, vertical position shall be expressed in terms of flight levels or altitudes as advised by ATC.
2.1.9 Flight level zero is located at the atmospheric pressure level of 1013.2 hPa (29.92 inHg). Consecutive flight levels are separated by a pressure interval corresponding to 500 ft (152.4 m) in the International Standard Atmosphere.
2.1.10 For all flights operating at or below the transition altitude, altimeter shall be set to the appropriate QNH derived from an available source.
2.2   QNH for aircraft operating at or below the transition altitude
2.2.1 Pilot who operating an aircraft at or below the transition altitude shall set an altimeter to the currently reported QNH of the nearest station along the route of flight, except as provide in 2.2.2 and 2.2.3.
2.2.2 Pilot who operating an aircraft operating in a terminal control area or a terminal control zone shall set an altimeter to the currently reported QNH of the major aerodrome of that airspace, which will be given by ATC.
2.2.3 When there is no appropriate available station, pilot shall set an altimeter to the elevation of the departure aerodrome until the appropriate QNH can be obtained.

Note: Pressure-altitude-derived level information displayed to the controller and level received from a pilot by radiotelephony might be vary due to different pressure setting.ATC shall comply with criteria as stated in ICAO doc 4444 paragraph 8.5.5 Level information based on the use of pressure-altitude information.

2.3  Take-off and climb
2.3.1 Altimeter setting is made available to aircraft in the routine takeoff and climb instructions.
2.3.2 Vertical displacement of aircraft during climb is controlled by reference to altitude until passing the transition altitude above which vertical displacement is controlled by reference to flight level.

Note: The word “controlled” is used in a composite sense in that a pilot will wish to fly his aircraft on predetermined flight levels or altitudes and ATS will wish to advise a pilot the availability of flight levels or altitudes: both are concerned with vertical position of aircraft.

2.4  Vertical Separation - en-route
2.4.1 Aircraft en-route in the Bangkok FIR (irrespective of whether IFR or VFR) shall be flown at flight levels or altitudes where appropriate.
2.4.2 When complying with the table of cruising levels in Civil Aviation Board (CAB) Regulation on Rules of the air, or for VFR flight above 900 metres (3 000 feet), aircraft shall be flown at levels corresponding to the tracks shown in the following table:
TRACK
From 000 degrees to 179 degreesFrom 180 degrees to 359 degrees
IFR FlightsVFR FlightsIFR FlightsVFR Flights
LevelLevelLevelLevel
FLFeetMetersFLFeetMetersFLFeetMetersFLFeetMeters
 1000300--- 2000600---
 3000900 35001050 40001200 45001350
 50001500 55001700 60001850 65002000
 70002150 75002300 80002450 85002600
 90002750 95002900 100003050 105003200
110110003350115115003500120120003650125125003800
130130003950135135004100140140004250145145004400
150150004550155155004700160160004900165165005050
170170005200175175005350180180005500185185005650
190190005800195195005950200200006100205205006250
210210006400215215006550220220006700225225006850
230230007000235235007150240240007300245245007450
250250007600255255007750260260007900265265008100
270270008250275275008400280280008550285285008700
290290008850   300300009150   
310310009450   320320009750   
3303300010050   3403400010350   
3503500010650   3603600010950   
3703700011300   3803800011600   
3903900011900   4004000012200   
4104100012500   4304300013100   
4504500013700   4704700014350   
4904900014950   5105100015550   
etc.etc.    etc.etc.etc.   
2.5  Approach and landing
2.5.1 A QNH altimeter setting is made available in the routine approach and landing instructions.
2.5.2 A QFE altimeter setting is made available on request in approach and landing clearance but reports to ATC are to be made in altitude.
2.5.3 Vertical displacement of aircraft during approach is effected by reference to flight level until passing the transition level below which vertical displacement is controlled by reference to altitude, except as provided in 2.5.4.
2.5.4 After approach clearance has been issued and the descent to land is commenced, the vertical position of an aircraft above the transition level may be by reference to altitude (QNH) provided that level flight above the transition altitude is not indicated or anticipated.
2.6  Missed Approach
2.6.1 The relevant portions of paragraph 2.3, 2.4 and 2.5 shall be applied in case of a missed approach.

3.  Procedure applicable to operators and pilots

3.1  Flight Planning
3.1.1 The levels at which a flight is to be conducted shall be specified in a flight plan:
3.1.1.1 in terms of flight levels, if the flight is to be conducted at or above the transition level; and
3.1.1.2 in terms of altitudes, if the flight is to be conducted in the vicinity of an aerodrome and at or below the transition altitude.

Note 1: Short flight in the vicinity of an aerodrome may often be conducted only at altitudes below the transition altitude.

Note 2: Flight levels are specified in the flight plan by number, and not in terms of feet in the case of altitudes.