ENR 1.7 ALTIMETER SETTING PROCEDURES

1. Introduction

The altimeter setting procedures in use generally conform to those contained in ICAO Doc 8168 Volume I, Part 6, and are given in full below.

Transition altitudes are given on the instrument approach charts and are described in paragraph 2.1.2 below.

QNH reports and temperature information for use in determining adequate terrain clearance are provided from the air traffic services. QNH values are given in hectopascals.

2. Basic altimeter setting procedures

2.1 General

2.1.1 The transition altitude for Sir Seewoosagur Ramgoolam International Airport is 4000 feet i.e the height of the highest terrain plus 1200 feet.

2.1.2 The transition level for Sir Seewoosagur Ramgoolam International Airport is varied in accordance with the following table:

QNH Transition Level
980 HPA and above 60
945 HPA to 979.9 HPA 70
2.1.3 The minimum safe altitudes for Sir Seewoosagur Ramgoolam International Airport are as follows:

Minimum Safe Altitude within a radius of 25 NM centered on DVOR/DME “PLS” Sector in magnetic degrees homing on DVOR/DME “PLS”
3100 ft 195° to 285°
2600 ft 285° to 059°
3800 ft 059° to 195°
2.1.4 Vertical positioning of aircraft when at or below the transition altitude is expressed in terms of altitude, whereas such positioning at or above the transition level is expressed in terms of flight levels. While passing through the transition layer, vertical positioning is expressed in terms of altitude when descending and in terms of flight levels when ascending.

2.1.5 Flight level zero is located at the atmospheric pressure level of 1 013.2 HPA (29.92 in). Consecutive flight levels are separated by a pressure interval corresponding to 500 ft (152.4 m) in the standard atmosphere.

Note :- Examples of the relationship between flight levels and altimeter indications are given in the following table, the metric equivalents being approximate:

Flight level number Altimeter indication
Feet Metres
10 1000 300
15 1500 450
20 2000 600
50 5000 1500
100 10000 3050
150 15000 4550
200 20000 6100
2.2 Take-off and climb

2.2.1 A QNH altimeter setting is made available to aircraft in taxi clearances prior to take-off.

2.2.2 Vertical positioning of aircraft during climb is expressed in terms of altitudes until reaching the transition altitude above which vertical positioning is expressed in terms of flight levels.

2.3 Vertical separation - en- route

2.3.1 Vertical separation during en-route flight shall be expressed in terms of flight levels at all times "during an IFR flight and at night".

2.3.2 IFR flights, and VFR flights above 900 m (3 000 ft), when in level cruising flight, shall be flown at such flight levels, corresponding to the magnetic tracks shown in the following table, so as to provide the required terrain clearance:

000°-179° 180°-359°
IFR VFR IFR VFR
Flight level number 10 20
30 35 40 45
50 55 60 65
70 75 80 85
90 95 100 105
... etc. ... etc.
270 280
290 310
330 350
etc. etc.
Note:- Some of the lower levels in the above table may not be usable due to terrain clearance requirements.
2.4 Approach and landing

2.4.1 A QNH altimeter setting is made available in approach clearance and in clearance to enter the traffic circuit.

2.4.2 QFE altimeter settings are available on request.

2.4.3 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 altitudes.

2.5 Missed approach

2.5.1 The relevant portions of 2.1.4, 2.2 and 2.4 shall be applied to the event of a missed approach.

3. Procedures applicable to operators (including pilots)

3.1 Flight planning

The levels at which a flight is to be conducted shall be specified in a flight plan in terms of:

a) flight levels if the flight is to be conducted at or above the transition level, and

b) altitudes if the flight is to be conducted in the vicinity of an aerodrome and at or below the transition altitude.

Note 1. - Short flights in the vicinity of an aerodrome may often be conducted only at altitudes below the transition altitudes.

Note 2. - Flight levels are specified in a plan by number and not in terms of feet or metres as is the case with altitudes.

4. Tables of cruising levels

The cruising levels to be observed when so required are as follows:

a) in areas where, on the basis of regional air navigation agreement and in accordance with conditions specified therein, a vertical separation minimum (VSM) of 300 m ( 1000 ft ) is applied between FL 290 and FL 410 inclusive:*

TRACK*

From 000 to 179 degrees From 180 degrees to 359 degrees
IFR Flights VFR Flights IFR Flights VFR Flights
Altitude Altitude Altitude Altitude
FL Metres Feet FL Metres Feet FL Metres Feet FL Meters Feet
-90

- - - 0

- - -
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 1850 6000 65 2000 6500
70 2150 7000 75 2300 7500 80 2450 8000 85 2600 8500
90 2750 9000 95 2900 9500 100 3050 10000 105 3200 10500
110 3350 11000 115 3500 11500 120 3650 12000 125 3800 12500
130 3950 13000 135 4100 13500 140 4250 14000 145 4400 14500
150 4550 15000 155 4700 15500 160 4900 16000 165 5050 16500
170 5200 17000 175 5350 17500 180 5500 18000 185 5650 18500
190 5800 19000 195 5950 19500 200 6100 20000 205 6250 20500
210 6400 21000 215 6550 21500 220 6700 22000 225 6850 22500
230 7000 23000 235 7150 23500 240 7300 24000 245 7450 24500
250 7600 25000 255 7750 25500 260 7900 26000 265 8100 26500
270 8250 27000 275 8400 27500 280 8550 28000 285 8700 28500
290 8850 29000 300 9150 30000
310 9450 31000 320 9750 32000
330 10050 33000 340 10350 34000
350 10650 35000 360 10950 36000


370 11300 37000


380 11600 38000


390 11900 39000


400 12200 40000


410 12500 41000


430 13100 43000


450 13700 45000


470 14350 47000


490 14950 49000


510 15550 51000


etc. etc. etc.


etc. etc. etc.


* Except when, on the basis of regional air navigation agreements, a modified table of cruising levels based on a normal vertical separation minimum of 300 m ( 1000 ft ) is prescribed for use, under specified conditions, by aircraft operating above FL 410 within designated portions of the airspace.

** Magnetic track, or in polar areas at latitudes higher than 70 degrees and within such extensions to those areas as may be prescribed by the appropriate ATS authorities, grid tracks as determined by a network of lines parallel to the Greenwich Meridian superimposed on a polar stereographic chart in which the direction towards the North Pole is employed as Grid North.

b) in other areas:

TRACK*

From 000 to 179 degrees From 180 degrees to 359 degrees
IFR Flights VFR Flights IFR Flights VFR Flights
Altitude Altitude Altitude Altitude
FL Metres Feet FL Metres Feet FL Metres Feet FL Metres Feet
-90 - - - 0 - - -
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 1850 6000 65 2000 6500
70 2150 7000 75 2300 7500 80 2450 8000 85 2600 8500
90 2750 9000 95 2900 9500 100 3050 10000 105 3200 10500
110 3350 11000 115 3500 11500 120 3650 12000 125 3800 12500
130 3950 13000 135 4100 13500 140 4250 14000 145 4400 14500
150 4550 15000 155 4700 15500 160 4900 16000 165 5050 16500
170 5200 17000 175 5350 17500 180 5500 18000 185 5650 18500
190 5800 19000 195 5950 19500 200 6100 20000 205 6250 20500
210 6400 21000 215 6550 21500 220 6700 22000 225 6850 22500
230 7000 23000 235 7150 23500 240 7300 24000 245 7450 24500
250 7600 25000 255 7750 25500 260 7900 26000 265 8100 26500
270 8250 27000 275 8400 27500 280 8550 28000 285 8700 28500
290 8850 29000 300 9150 30000 310 9450 31000 320 9750 32000
330 10050 33000 340 10350 34000 350 10650 35000 360 10950 36000
370 11300 37000 380 11600 38000 390 11900 39000 400 12200 40000
410 12500 41000 420 12800 42000 430 13100 43000 440 13400 44000
450 13700 45000 460 14000 46000 470 14350 47000 480 14650 48000
490 14950 49000 500 15250 50000 510 15550 51000 520 15850 52000
etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc.
* Magnetic track, or in polar areas at latitudes higher than 70 degrees and within such extensions to those areas as may be prescribed by the appropriate ATS authorities, grid tracks as determined by a network of lines parallel to the Greenwich Meridian superimposed on a polar stereographic chart in which the direction towards the North Pole is employed as the Grid North.