Transition Altitudes

Transition Altitudes

26TH ANNUAL CONFERENCE, Nairobi, Kenya, 27-30 April 1987

WP No. 35

Transition Altitudes


At the 1986 conference SC 1 presented WP No 62 on Transition Altitudes. After discussion it was recommended that SC 1 should re-examine the subject of Transition Altitudes and develop policy recommendations where appropriate covering:

  1. The standardisation of Transition Altitudes on a region – wide basis;
  2. The use of Transition Altitudes higher than those recommended in ICAO PANS-OPS.

The PANS-OPS Para states that “the height above the aerodrome of the Transition Altitude shall be as low as possible but normally not less than 900m (3,000ft). ICAO introduced flight levels as a standard in order to avoid fatal accidents accruing due to misunderstandings and errors by using ever changing QNH settings. Therefore flight levels are used to separate aircraft from each other, and not from terrain.

A pilot wants a standard Transition Altitude at least on a regional basis if a world-wide is not obtainable. This makes it easier for him. But he has only aircraft to be concerned about, and the Transition Altitude is already printed on his maps/plates. So to him it is a matter of having them available at the right time. It is the controller who does all the work when it comes to the separation of aircraft. So he wants a low Transition Altitude which means lesser work and the chance to use flight levels as low as possible. It is much safer to work with only one pressure setting. Maybe a controller works 20 or more aircraft. With a transition altitude of 10,000 ft. Which IFALPA considers as the best compromise, the controller has to make sure that every aircraft is given the right QNH. Within one sector or area there might be several different QNH’s. When a low transition altitude is used, less work/strain is put on the controller and this means a more safe flow of traffic. The more you can cut down on R/T the more you keep the frequency open, and this is also in the interest of safety.

It is an advantage when transition altitudes correspond to each other. There will be problems if one area has a transition altitude of 10,000ft. And the next one has 3,000ft. But why have a high transition altitude if it does not suit the structure of an FIR’s airspace.

To Conclude

Standardisation of transition altitudes on a region – wide basis has taken place, and it can be in the interest of IFATCA that this continues where it is in the interest of safety. It is wrong if IFATCA comes up with a policy that states that transition altitudes shall be 10,000ft. Or higher. This will not be an improvement, but it will be a hazard to safety seen from a controller’s point of view. What is stated in ICAO PANS-OPS is sufficient for IFATCA.

It is recommended that:

It is recommended that Standardisation of transition altitudes on a region-wide basis be implemented where applicable.

Last Update: September 20, 2020  

December 1, 2019   1093   Jean-Francois Lepage    1987    

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