Re: Snow on wings

From:         peter neville gurnell <pgurnell@direct.ca>
Organization: Canada Internet Direct, Inc.
Date:         02 Jun 96 23:01:51 
References:   1
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whodgins@axess.com (W. Hodgins) wrote:
>
> Some time ago I was a passenger on a DC-9 flight out of Toronto in
> January as I recall. Looking out the window, I noticed a fair amount
> of snow on the wings...it was not removed and the aircraft took off
> with snow blowing off the wings as speed increased.
> I used to fly light aircraft in the early 70's and if I recall
> correctly we were supposed to ensure that nothing, not even frost,
> should be allowed to accumulate on the wings.
> What is the criteria for large jets...is an accumulation of light snow
> normally acceptable ?

The Canadian Air Regulations 540.2 (2) state

"No person shall takeoff or attempt to takeoff in an aircraft if any
frost, iece or snow is adhering to any critical surface of the aircraft."

They do not define "adhering", however, in ground icing conditions a
pre-flight external inspection of the ice detection strips (two black
stripes painted on wings) and the critical surfaces (wings, control
surfaces, horizontal and vertical stabilizers or any other stabilizing
surface of an aircraft) must be carried out by a qualified person
(flight crew member or qualified ground personnel) to determine if they
are free of contamination.  This inspection is to be carried out as
close as possible but not exceeding 5 minutes prior to takeoff.

Can an aircraft take off with snow on the wings?  Yes.  Is an aircraft
allowed to take off with snow on the wings? No.

It was the actions of a flight crew of one of Air Canada's Connector
Airlines, Air Ontario in an F-28 that crashed shortly takeoff (Dryden,
Ontario, 1989) due to wing surface contamination that brought this whole world of regulations
down upon us.

Cheers, Peter