View Full Version : Temperature inversions

28th Jun 2002, 06:39
Would anyone who operates into and out of areas which experience temperature inversions, such as the Middle East, care to comment on what operating procedures or recommendations they or their airline follow for dealing with this type of phenomenon.

Would also be interested to hear any stories of encounters you may have had resulting from temperature inversions such as climb performance degradation after take off.


28th Jun 2002, 06:55
Though my company doesnt have specific procedures when dealing with temp inversion but personally what i would do is to calculated my takeoff climb limit based on the reported higher temp rather than the surface temp. it would result in a more limiting weight but so be it. either we wait for the temp to come down or offload some cargo to make the acft lighter.


28th Jun 2002, 07:18
Operated in the Middle East, and like you found the aircraft nearly stops climbing when entering the low level temp inversion just after takeoff.
The policy introduced was to use no derates on the engines on takeoff into a known or suspected inversion.

28th Jun 2002, 10:56
We add the reported temperature inversion to the actual temperature for all takeoff calculations. This results in severe payload restrictions and tech stops on certain sectors, I guess that its just as well that we arent in this business to make money :)

The highest temperature inversion that I have seen reported was +16C at RUH.


Noise Unit
4th Jul 2002, 22:56
In the Gulf region, how often do you encounter these conditions?

Are there any other parts of the world where you regularly see temperature inversions?

Questions, questions?:confused:

5th Jul 2002, 04:08
During the summer, we can expect to see Temperature Inversions on a daily basis, hence our rather extreme solution to the problem!


Capt. Crosswind
5th Jul 2002, 09:31
Out of Dubai & Bahrain we used to not derate under any circumstances & make an educated guess at the temp in the inversion. F/E would note the EPR for this temp & go to this EPR (or near it) as soon as the inversion was encountered,then fine tune for actual temp. Inversion usually kicked in around 400 -600 feet.
It seemed that the later at night the stronger the inversion,which figures. Sharpest I remember was about +15 degrees out of Bahrain at 0400 local. Technique where you did not have 100 miles of clearway in the event of EFOT/O would be another matter.

Semaphore Sam
6th Jul 2002, 00:00
Mutt & I work for the same carrier. If, for example, the current temp is 42C, reported or forecast inversion is +8C, we enter the charts at 50C for actual/derate values (max weights & thrust). Very restrictive, but very safe. Happens often in summer, in JED, RUH, & DMM. Our carrier accepts the penalties without question.