AIP for GAMBIA (section ENR-1.7) valid from 23 JAN 2025

ENR 1 General Rules and Procedures

ENR 1.7 ALTIMETER SETTING PROCEDURES

GENERAL

1.1

The altimeter setting procedures in use generally conform to those contained in ICAO Doc 8168-OPS/611, Vol. I, Part 6 and are given in full below.

1.2

The Transition Altitude (TA) is 2500FT and the Transition Level (TL) is FL40 for Banjul International Airport and are given on instrument approach charts.

1.3

QNH reports and temperature information for use in determining adequate terrain clearance are provided by Air Traffic Control Banjul. QNH values are given in whole millibars.

BASIC PROCEDURES

2.1

General

2.1.1

The transition layer for the Banjul Control Zone is fixed with the Transition Altitude being at 2500 FT and the Transition Level being at FL 40, both being permanently separated.

Vertical positioning of aircraft when at or below the Transition Altitude is expressed in terms of :

ALT, when at or below the Transition Altitude or when descending through the transition layer; and

FL, when at or above the Transition Level or when ascending through the transition layer.

2.1.2

FL zero is located at the atmospheric pressure level of 1013.2 hPa (29.92 IN). Consecutive flight levels are separated by a pressure interval corresponding to 500 feet (152.4 meters) which is the standard atmosphere.

Note:

Examples indicating the relationship between flight level and altimeter indications are given in the following table, the metric equivalents being approximate.

2.2

Take off and Climb

2.2.1

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:

ALT, until reaching the Transition Altitude; and

FL, when above the Transition Altitude.

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.

2.3.2

When complying with the cruising levels in Appendix C of ICAO Annex 2, an aircraft shall be flown at FLs corresponding to the magnetic tracks as shown in the following table.

Tables of Cruising Levels (Magnetic Tracks)
From 000° to 179°						From 180° to 359°
IFR Flights			VFR Flights			IFR Flights			VFR Flights
FL	Altitude		FL	Altitude		FL	Altitude		FL	Altitude
FL	Meters	Feet	FL	Meters	Feet	FL	Meters	Feet	FL	Meters	Feet
				450	1 500					750	2 500
30	900	3 000		1 050	3 500	40	1 200	4 000		1 350	4 500
50	1 500	5 000		1 700	5 500
70	2 150	7 000				60	1 850	6 000
90	2 750	9 000	Class A Airspace			80	2 450	8 000	Class A Airspace
110	3 350	11 000	No VFR flights			100	3 050	10 000	No VFR flights
130	3 950	13 000	above 5500 ALT feet			120	3 650	12 000	above 4500 ALT feet
150	4 550	15 000				140	4 250	14 000
170	5 200	17 000				160	4 900	16 000
190	5 800	19 000				180	5 500	18 000
210	6 400	21 000				200	6 100	20 000
230	7 000	23 000				220	6 700	22 000

Tables of Cruising Levels (Magnetic Tracks)
From 000° to 179°						From 180° to 359°
IFR Flights			VFR Flights			IFR Flights			VFR Flights
FL	Altitude		FL	Altitude		FL	Altitude		FL	Altitude
FL	Meters	Feet	FL	Meters	Feet	FL	Meters	Feet	FL	Meters	Feet
250	7 600	25 000				240	7 300	24 000
270	8 250	27 000				260	7 900	26 000
290	8 850	29 000				280	8 550	28 000
330	10 050	33 000				310	9 450	31 000
370	11 300	37 000				350	10 650	35 000
410	12 500	41 000				390	11 900	39 000
450	13 700	45 000				430	13 100	43 000
490	14 950	49 000				470	14 350	47 000
etc.	etc.	etc.				510	15 550	51 000
						etc.	etc.	etc.

2.4

Approach and Landing

2.4.1

A QNH altimeter setting is made available in routine approach and landing instructions.

2.4.2

QFE altimeter settings are available on request.

2.4.3

Vertical positioning of aircraft during approach is controlled by reference to:

FL, until reaching the Transition Level; and

ALT, when below the Transition Level.

2.5

Missed Approach

2.5.1

The relevant portions of paragraphs 2.1.1, 2.2 and 2.4 of these subsections shall be applied in the event of a missed approach.

DESCRIPTION OF ALTIMETER SETTING REGION

NIL

EN-ROUTE PROCEDURES - FLIGHT LEVELS

En-route flights penetrating the Banjul CTR are not allowed within the transition layer between 2500 FT and FL40 unless specifically instructed by ATC.

PROCEDURES APPLICABLE TO OPERATORS (INCLUDING PILOTS

5.1

Flight Planning

5.1.1

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

in terms of Flight Levels if the flight is to be conducted in the vicinity of the aerodrome and when at or above the Transition Altitude;

in terms of altitude if the flight is to be con-ducted in the vicinity of the aerodrome and when at or below the Transition Altitude.

5.1.2

The level selected should ensure :

adequate terrain clearance for the entire route;

satisfy ATC requirements;

and be compatible with the table of cruising levels as shown on page ENR 1.7-1.

Pre-flight Operational Test

5.1.3

With the aircraft at a known elevation on the aerodrome and the altimeter subscale set to the appropriate pressure value, ensure that the difference (if any) between the published elevation (plus the height of the altimeter above this) and the value indicated is within the permissible range for that instrument.