INFO Last updated on 15 JUL 2021                                                                        PDF Version - Printable

ENR 1.7    ALTIMETER SETTING PROCEDURES

INTRODUCTION

The altimeter setting procedures in use generally conform to those contained in ICAO DOC 8168-OPS/611 Vol. 1 without exception.

Transition altitude (TA) is given on instrument approach charts.

QNH and temperature information for the use in determining adequate terrain clearance are provided in MET broadcast and is available on request from ATS units. QNH values are given in whole Hpa.

BASIC ALTIMETER SETTING PROCEDURES

General

A common transition altitude 11000FT (3350M) is established for    KATUNAYAKE / Bandaranaike Intl, Airport Colombo (VCBI), MATTALA/Mattala Rajapaksa Intl. (VCRI) and  Ratmalana / Colombo Intl. Airport Ratmalana (VCCC) and KANKESANTURAI / Jaffna Intl. Airport (VCCJ).

A transition level (TL) of FL 130 is established while maintaining a minimum thickness of 1000ft of transition layer.

Vertical position of an aircraft is expressed in terms of;

 a).   Altitudes, when at or below the transition altitude or when descending through the transition layer, and

 b).   Flight Levels, when at or above the transition level or when ascending through the transition layer.

Flight level zero is located at the atmospheric pressure level of 1013.2 Hpa (29.92inc). Consecutive flight levels are separated by a pressure interval corresponding to 500ft in the standard atmosphere.

Note:  Example of the relationship between flight levels and altimeter indication is given inthe following table,

          the metric   equivalents  being approximate;      

Take-off and climb

Current QNH altimeter setting is made available to aircraft in taxi clearance before take-off if it differs from the previous broadcast in ATIS.

Vertical position of aircraft during climb is given reference to;

a)     Altitudes, until reaching the transition altitude; and      

b)    Flight Level, when above the transition altitude

 2.3  

Vertical separation - Enroute

Vertical separation enroute is assessed in terms of;

a).   Altitudes, when at and below the transition altitude; and 

b.   Flight Levels, when above the transition altitude.

All en-route flights should be conducted in accordance with the Semi-circular system of cruising levels corresponding to the magnetic tracks and shown in the Table of Cruising Levels (Click to view)as will provide the required terrain clearances.   

Approach and landing

Current QNH altimeter setting is made available in approach clearance and in the landing clearance if it differs from the previous QNH broadcast in the ATIS.

A QFE altimeter setting will be made available on request but reports to ATC should be made on the QNH value.

Vertical positioning of aircraft during approach is controlled by reference to flight levels until reaching the transition level below which positioning is controlled by reference to altitudes.

Missed Approach

The relevant portions of paragraphs 2.1.2, 2.2 and 2.4 shall be applied in the event of missed approach.

DESCRIPTION OF ALTIMETER SETTING REGION

There is a single altimeter pressure setting which covers the entire Colombo FIR.

PROCEDURES APPLICABLE TO OPERATORS, INCLUDING PILOTS.

Flight Planning

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

a)  in terms of flight level(s) if the flight is to be conducted at or above the transition level; and

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

The flight level(s) selected for a flight plan;

a)   ensure adequate terrain clearance at points along the route to be flown.

 b).  satisfy air traffic services requirements; and

 c).  be compatible with the application of the semi-circular cruising levels rule.

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

      ii).   Flight levels are specified in the flight plan by number, and not in the term of feetor meters

             as in case of altitudes.selected for a flightplan;    

                                                                             (END of Sub Section ENR 1.7)                                  >>>>Back to Top