De-icing

[matblack]

They had some stormy weather in Scandinavia yesterday with thunder, lightning & hail. When I drove to the airport the rain & hail had frozen to the road making it particularly tricky. In the morning my rental car still had ice all over, as was the road.

I took an early flight from a Scandinavian airport this morning and whilst we were at the gate I noticed that the wings had some light frost on the top. The aircraft type was a B737 500. It didn't de-ice.

The air temp. at 6.30am this morning was +2 degC.

Is de-icing not so critical on this aircraft type or is frost not considered an issue in any case?

Do the scandinavian based airlines not de-ice as frequently as other carriers because they are more familiar with icing?

Obviously the frost wasn't an issue in this case (or I wouldn't be writing this) but I was just curious.

[rubik101]

If the upper wing surfaces are not 'clean', don't fly it. QED

[Bearcat]

supplementary procedures in the boeing manual reads...."t/o with light coatings of frost, upto 3mm in thickness on lower wing surfaces due to cold fuel is permissible;however; all leading edge devices;all control surfaces; tab surfaces;upper wing surfaces and balance panel cavities must be free of snow or ice"

make your own conclusions.

[bafanguy]

Putting fuel in the tanks will not take care of frost on ailerons, slats ( the most critical area ), or spoiler panels. And if there is frost on the wing areas, how much is on the horizontal stab, elevators ? All these surfaces are critical to acft control.

If one takes off with frost on critical surfaces, he can't possibily know how much is too much where aerodynamics/control/stability is concerned. There is nothing one can figure out under operational conditons to know if a "little bit" will be OK this time. At this point he is a test pilot with passengers.

In operational circumstances, the only thing one can know for sure is that no frost/ice/snow will be OK. That's why there are regulations and operational procedures addressing this condition.

It is sometimes an uphill battle to get cooperation from ground crews when necessary to clear a "little bit" of frost. It's a nasty, expensive job. They won't understand why or want to undertake the task in some cases.

They put the fourth stripe on your sleeve for a reason. Use it when you know what needs to be done. You are the one with the airplane strapped to your butt.

[Basil]

Depends what's caused the frost. If it's subzero fuel then it may only be on the tank area and refuelling with warm fuel could do the trick.
Likely scene could be a 5hr cruise with dest temp 5-10deg and humid.
Good idea to have a ballpark figure in your head re the max fuel you can arrive with and clear frost by refuelling at an airport with no de-icing facilities and, as bafanguy says, be prepared to tell ops/CP/DFO to fly it themselves if they object.

[AUTOGLIDE]

Does anyone really think a Scandinavian airline is likely not to de-ice properly? If it was the case they wouldn't have a single aircraft left. Not all de-icing is done at the gate either.

[dolly737]

Here's an interesting article:

NTSB Advisory: Alert to Pilots: Wing Upper Surface Ice Accumulation (http://www.ntsb.gov/pressrel/2004/041229.htm)