PPRuNe Forums - Polish the Ice?

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- - Polish the Ice? (https://www.pprune.org/tech-log/314181-polish-ice.html)

Quote:

While it is true that many new(er) types will not tolerate frost on the wings (polished or not), many older types (DC-3, as an example) can be flown quite safely with well-polished frost.
As for frost on the underside of wings on jet aircraft, B707's (again, as an example) had no restrictions whatsoever in this regard, so a few youngsters who, having never flown older types, will more than likely be unaware.

What about the big......Aaaaah Lockheed?

Quote:

What about the big......Aaaaah Lockheed?

The big Lockheed three-holer must be de-iced...however, frost on the underside of the wing (as you might find when the aircraft is landed in a humid climate after a long flight), no problem whatsoever.
None, zip, nada.

The polishing of Frost.

Here we go again getting back into history, and a modern generation that seem to have missed something on the way up.

The procedure was "To remove FROST from the surfaces" It did not say ICE. Various parts of the world are prone to heavy frost, and may not have freezing rain or large snowfalls.

On the older big pistons, DC-3, DC-4, DC-6 etc. and various English and other airplanes there was a procedure to remove "FROST" from the surfaces by passing a length of dry fire hose from front to back, or coarse rope, and with a see-saw motion it would polish the "FROST" off. Been there done that etc. back in the '50's and '60's.

Those old wing sections were nowhere near as critical as the new ones with rivits and bits sticking up or stuck on the top surface. Big propellers passing large amounts of air over those surfaces made for lift as well, not so today with your jets.

When you have a wing such as the CRJ that has a peformance penalty for any sealant that may be missing from behind the leading edge section where it is fixed to the wing, and no dents allowed in that leading edge section, or "bondo" repairs, you have a problem airfoil, otherwise known, and proven to be, critical.

We have come a long way with our knowledge, unfortualty as seems to be too frequent in this business at some great cost in lives and machines, but we do need to remember that we have not yet reached perfection although we are trying hard.

We have new rules, "if it has frost ice or snow on it, don't fly it".

The younger generation could do well to read some of the history that came with the experience that has got them where they are today, and they may then understand a bit better without the ridicule that seems so often to come in some Pprune threads. It is not all in school books and "on line". It is experience!!

Speedbird 48.

Absolutely right, Speedbird 48.

FAA NPRM now released to remove references to "polished frost".

Quote:

SUMMARY:
The FAA is proposing to remove provisions in its regulations that allow for operations with “polished frost” (i.e., frost polished to make it smooth) on the wings of airplanes operated under parts 125, 135, and certain airplanes operated under part 91. The rule would increase safety by not allowing operations with polished frost, which the FAA has determined increases the risk of unsafe flight

Would "it is about time, FAA", be too harsh!!

GF

There is an additional problem

Ice builds up on ice which is already there faster than on clean surfaces. If you polish frost, you may actually be able to fly, BUT there is now a layer of ice where the anti-icing can't get at it, and where ice can now build up when on a properly de-iced surface, it wouldn't.

Do your de-icing properly, and watch your holdover times! Accept no substitute.

OORW