De -Anti icing 738
The issue I would like to discuss with you is regarding Anti-De icing
procedure.
The procedure itself is easy to understand but something caught my attention last winter.
There you are during the turn around time which may take from one to two
hours time . It starts to snow. It is moderate and heavy in some cases or it could be light / moderate freezing rain. Flaps are up.
During the waiting period the wings becomes all covered with snow and of
course some melts at the contact with the wing to freeze again.
Time is up and we have to DE ICE/ANTI ICE now. The truck comes and sprays the wing.
Ok here is the catch. Since flaps are up the LE are covering part of the wing.
If water ran underneath and froze my guess is that it won’t be removed or
probably only melted due to high temperature of the fluids used but not up to a 100%. Neither will that area be covered with a nice and even layer of ANTI ICE. I observed how big the area covered by the LE is and it is pretty big and in a very critical part of the wing.
Can anyone tell me more about this fact since I have not find any literature mentioning the matter. Should the DE ICING ANTI ICING be done with flaps down in order to uncover this area and make it subject to the same treatment as the rest of the wing?
If not properly De Iced and Anti iced once the flaps are extended for take
off, that area will be exposed to outside conditions making it vulnerable to
freeze or accumulate snow and therefore loose its performance.
Thanks