Takeoff at snow covered runway

[levashov]

Hi guys,

we all know that takeoff at snow covered runways are dangerous, as well as sometimes prohibited. Our local athorities still cleared pilots for t/o if the runway covered with the dry snow iless then 50 mm (1.9 inches) high.

Ive heard the story from one russian pilot of how he was taking off on a such runway, he said that at about 80 knots the acceleration is becoming very slow, and at Vr he was pulling his yoke much harder to lift off (and its kinda dangerous because after that you have accesive nose up position). The cause of this is probably the braking force causing by snow. But why accesive nose down C.G.?

If anybody here can provide me with ditailed information of how it physically works?
a) How do snow, or slush, or wet snow acting on: acceleration, braking action,

b) if anybody know advisory circulars,
c) NTSB invistigations concerning accidents and incidents because of this,
d) any recommendations from Boeing, Airbus, Bombardier, or
e) any articles about technics of how to liftoff in such conditions and avaoid of abrupt nose ups - i would be very thankful.

I just want to know precisely of this problem.

Thank you!