View Full Version : Icing of upper wing surface.

20th Apr 2003, 05:35
Do any of you clever boys & girls know where I might find guidance/ info. on upper wing surface icing?
I believe Boeing do have recommendations re tanking to ski destinations. The idea being that you don't want to descend with fuel cooled in the cruise in contact with the upper wing and thus greatly increasing the chances of icing.
I'd prefer Airbus data, they don't have such guidance but would be grateful for anything!
Many thanks:p

Bally Heck
20th Apr 2003, 07:30
For the 757 you should plan to land with not more than 9 tonnes to avoid upper surface icing.

Ski destinations are probably less of a problem than humid destinations as you will probably be de-iced anyway and the relative humidity will be low. Humid destinations will cause condensation to freeze on the upper surfaces with more than 9 tonnes.

My company gives no guidance on 767s. Probably because it is unlikely you would plan to land with something like 24 tonnes.

21st Apr 2003, 03:07
13.5T on the A330 (our SOPs) with the solution to transfer the outer tank with the colder fuel to the inner with the warmer fuel and the fact that the outer tank fuel will no longer be in contact with the upper skin.

Frank M
21st Apr 2003, 06:26
The SOP's in my company state for certain destinations (THR, AUH, DXB, BAH, CAI etc) that we should plan to land with less than 12 tons of fuel. I've actually had some icing in Dubai after a 6 hour flight with about 15 tons on board (this was before this 12 ton instruction; the value back then was 17 tons). This was a rather strange situation as the temperature was 22 degrees at the time, unfortunately the dewpoint was the same.....

Hope this helps.

P.S. I just saw I forgot to mention type : 767-300...

23rd Apr 2003, 13:51
Boeing has proposed to FAA and ATA (ALPA briefed) on their desire to allow departure with ice on the upper surface of the wings. Apparently SWA was the big gun in pushing for this. I don't know what specific proposals are but am confident of my source on this one.

30th Apr 2003, 00:01
I agree with that NOPERF.

Generally, the annoying patches of ice are no greater that 10 square feet on the wing root of the 737 NGs. There should be some reasonable limit for upper wing condensation frost caused by super cooled fuel. These ice patches generally manifest themselves several feet behind the leading edge, and I would be very surprised if engineering studies showed they represent a significant hazard.

I hope Boeing can modify the "Clean Wing Concept" with the FAA to introduce some common sense. The "Clean Wing Concept" was an overreaction to the Air Florida crash.