on flying with polished ice on your wing
 

Hello all.

FAA today published a SAFO on icing for Part 91, 125 and 135 operators.

Basically it is about possiblity of taking off with polished frosting on the wings or control surfaces (currently still allowed:eek: ).

To see more of it, here is the link.

Since I have worked at several OEMs on closely related problems I can safely say that this is the biggest no-no, from ANY point of view. Sadly from what we've seen in the last 10 years there exist a bunch of people (mostly bizjet crowd) willing to take off with accumulated ice (mostly overnight) or without anti-icing on.

Please take care and do have it (a-i) on before take-off anyway since the price can be too big.

The drop in lift is so large and the airflow is so screwed up with only few traces of ice that you really need to be very, very lucky in order to take off like this and survive.

By the way - polished icing - I mean really...:= := :=

Never, never consider flying with polished ice. That is why there is a hefty a-i system installed.

Cheers

Attempting to get airbourne with any contamination on the flying surfaces on an aircraft, you become a "test pilot". Aviation and aerodynamics are a highly developed science. Don't pioneer.

Yes indeed. Those guys get blow-able hatches and wear parachutes. :ok:

I wonder what these guys would say about that if they were still around.

Not polished ice but...
 

I've seen in FAR 91 type flying the practice of accepting loose snow on the wing, believe it will always blow off on take off. May be true in cases of dry snow, I'm not so sure that when it gets a bit wet, or sticky, this will happen. So I've found that blowing gently on the snow on the wing, or just flicking it with a finger, seems to be the sensible test. If it readily repositions itself well away or completely off the wing, seems sensible to take off. If it at all just moves over a bit, and stops, then it filts definition of adhering.

The wording of the FAR addresses snow "adhering" to the wing. Has there been any clarification on exactly what adhering has meant?

Before anyone jumps in admonishing me for not using common sense, I only pose the question because I KNOW pilots different opinions on what adhering is meant to imply.

If there's a section of wet snow on part of your wing under that dry snow, which your quick "flick test" didn't (and probably can't) find, there may be two consequences:

1. you'll stall, crash and die
2. your obituary will blame you for the crash

No doubt a disticnt possibility, and for sure been done already. The horizontal stab can't even be reached in many cases to confirm it's condition. The reasoning has been the wings appear clear, so the tail must be too... Worked last time...

I only bring this up because a "tactile" hands on inspection by the crew can be anything from a detailed sweep of the entire surfaces using ladders etc, to a quick flick with the fingers. Seen it.

Jesus Christ, I can't believe I'm reading some of this stuff. If there is any doubt, THERE IS NO DOUBT, GET THE THING COMPLETELY DE-ICED. If you can't get it de-iced, DON'T GO. Get it now???? What frightens me is one day I might be a passenger with one of these pr***s up front.. I need a drink.

Twenty years ago a Chief Pilot of mine killed himself one night doing this. Ironically after warning us young’ns not to do it.

Yea, the snow will probably blow off. And in his case it did. Just not symmetrically. He died when the airplane violently rolled after rotation.

The only time this "adhering" argument has any reason to even exist is in very, very light snow in very, very cold temperatures when wind is keeping anything from accumulating. In other words, when the airplane is clean.

...and who knows what you will find under the snow.

I've done a bit of gliding and one of the planes at our club was iffy if the wings were wet. The "stall speed wings wet" was only a few k below the normal winching speed. The field bus carried several car wiper blades and some cloths to save your life with.

Ok, I guess my general point was meant for those in FAR 91 and other categories that are not obliged to turn on the anti icing "on".

Apparently guys in England (Birmingham, Challenger accident) did not do it. And they are not alone in not doing it.

It is not about flying in "known icing conditions" - it is about leaving you a/c small as a GA or as big as GV, Global or Challenger out on a tarmac overnight.

The icing on the cake can be so smooth you don't feel it.

If the OEM gave you already a hefty blow torch in form of the anti icing (believe me, I've seen burned ribs on Challengers!) you better use it.

Res ipsa loquitur

It is really just a matter of using common sense and knowing your aircraft. Sometimes you can't get every last millimeter of frost off your critical surfaces. If you are in an F-28 or baby DC-9, you never screw around with contamination. If you are on a Twin Otter lightly loaded, with other considerations taken into account, you may decide to go. I did.

The Twin Otter has been known to pitch down viciously with flaps extended past 10 and ice on the tail.

Glad that it worked out for you that time.

That is correct.....for inflight icing on the leading edge of the horizontal stabilizer. But it is difficult to apply deice fluid for this situation prior to landing. However I have yet to hear about a bit of frost doing this on takeoff. Once again, knowledge about your aircraft.
Always good to remove what you can but scraping with a broom will leave some frost residue and there could be a little bit on the vertical tail. Should I cancel the flight? Unfortunately no deice fluid is available in most arctic locations. Or the Antarctic as well from what I remember. People make posts like every location where aircraft fly is a major airport.
There is a reason why the FAA allows polished frost. Because, for example, in places like much of Alaska and similar locations you are in a small plane in the middle of nowhere where there are no de-ice facilities. There is a whole other world out there from operation on a 742. Of course you get the idiots who take things to the extreme and crash leaving government agencies no choice but to mandate a clean wing concept or no contamination on the critical surfaces. A good idea, but then there is the real world.
I expect it will work out for me next time as well.

With regard to de-icing - does a requirement to remote hold; taxy time over 20 minutes to departure point; last minute departure delay (late CTOT change/MDI/weather) etc etc have any bearing on your decision to depart after having de-iced on the gate? Do Company SOPs require you to cancel the departure and return to the gate to de-ice once again?

Seen it happen many, many times.


I still don't understand why pilots insist on putting their a/c and occupants at risk after all these years.

If it's got anything more than a light frost on the upper surface GET IT DE-ICED!
It's a helluvalot cheaper than the alternative smoking hole.

The only time I've seen "polished ice" is in the case of very light frost wiped with a cloth until it was basically gone or smooth. Essentially, the new guidance prohibits this action, and light frost will require a de-ice. Deicing is the only sure fire way to go legally, and safely too.

Turin

Agree, fully, with your statement!

I do not understand some pilots still being capable to take a brief look at the wing after the a/c has spent a night on a freezing tarmac (seen that in YUL, January, that day was -23C + 40 km/h wind?!?!?!).

He was one lucky bastard to fly away like that!:ooh:

Is it so hard and expensive to pay a visit to a de-icing facility for a shower plus TO TURN ON THE ANTI ICING TO MAX??

We all know it will burn a little bit more fuel (especially at take off) but it is still better then trying to test the new aerodynamic profile of the wing, right? :}

Cheers,

After an interesting low level excursion in a ravine off the end of a runway while building airspeed (yes -- I had scraped all the frost between the rivet lines) I took to carrying a couple extra containers of windshield washer fluid along with a windshield sponge/squeegee.

No way would I dream of flying without a clean wing.

Exceptions can be made for frost over/under wing tanks where approved by manufacturer.

'currently still alowed'.....actually on Boeing aeroplanes it's NOT allowed to have any kind of deposits on wing surface,flight controls,leading edge....
Only thing allowed it's frost on the fuselage-light frost,you have to be able to see the markings,and ice on the underside of the wing ,due to cold fuel-this is also limited in length..but again the upperside of the wing must be clear.It is suggested that ,if any doubt,you should check by hand the evental presence of clear ice.