A380 wingtop Ice formation.
 

Flew intp Manchester on an EK A 380 and as we descended, noticed this Ice formin on both wings, in the same places. The Main square is clear, but there was also another section on the leading edge.

Any ideas what causes it ?

http://i518.photobucket.com/albums/u...28_1537171.jpg

http://i518.photobucket.com/albums/u...28_1535241.jpg

Speaking as a complete non-expert, it must be something cold inside the wing and my guess would be fuel, which can get pretty chilly at 37,000' (this was the problem with BA38).

We had just come down steadily from 40,000', having been there for a lot of the flight.

On the tail mounted camera, you could see the identical pattern on the starboard wing too. Peculiar.

It'll be where there is a different material under the skin thereby making the outer skin slightly less or more of a heatsink than the surrounding area.

I am not exactly sure where in the wings there are composites, but perhaps a composite section with a metal section underneath or vice versa ?