Frost on wings?

[Cutlass1287]

According to my CFI, we can safely fly if we polish and frost or ice on the wings to make it smooth.

According to the FAA and the ASF, it needs to be removed completely.

Whats the deal?

 

[mayday1]

uh... you want to remove any ice, frost, etc. from the wings before you fly. Just because you polish a rough, frosty surface that doesn't make it safe... ice or frost will change the camber of the wing, add weight, etc. Ice is one of pilot's most dreaded elements.. don't take any chances... just my $.02.

 

[moxiepilot]

I agree with you and not your CFI, the reason as follows:

I think where your CFI got the "polish the frost" theory was from reading a Jeppeson manual. While not completely inaccurate with their information, they do have mistakes. Therefore when discussing topics with lets say an FAA examiner, only FAA books should be referenced. Not ASA not Jepp, only FAA.

Bearing this in mind, Aviation Weather, AC 00-6A (1975 he he) states:

pp102 - 103 - "Always remove ice or frost from airfoils before attempting takeoff." There is no mentioning of polishing anything in any FAA publication I can find. I would like to hear if someone can find an FAA publication with that information. Because I remember having heard the same thing somewhere once.

 

[mayday1]

Your CFI might be thinking of statements such as "frost creates a rough surface on the wing which can result in early separation of airflow from the wing surface.." thereby concluding that polishing it smooth is an acceptable remedy. Bottom line, don't fly with any frost, ice, or other $hit on your wings.

 

[minitour]

I would like to hear if someone can find an FAA publication with that information. Because I remember having heard the same thing somewhere once.

Sure thing.

14 CFR 135.227
(a) No pilot may take off an aircraft that has frost, ice, or snow adhering to any rotor blade, propeller, windshield, wing, stabilizing or control surface, to a powerplant installation, or to an airspeed, altimeter, rate of climb, or flight attitude instrument system, except under the following conditions:

(1) Takeoffs may be made with frost adhering to the wings, or stabilizing or control surfaces, if the frost has been polished to make it smooth.

BUT.

I agree with you. Remove it. I've seen the data and I've gotten ice on a 172 (unintentionally). It's not fun flying full power at 90kts with 0 flaps on final. Just remove it.

-mini

 

[Singlecoil]

I used to fly 207's and 402's in western Alaska. You do indeed polish it smooth with a big ol' push broom (be careful around the vortex generators on the 402). Then add about 5 knots to your rotation speed and be on your way. The rest will sublimate off before you land.

 

[SkyWestCRJPilot]

When I flew Part 135 we could polish the frost. Under SkyWest's Part 121 rules we have to be completely clear of ice or anything, except frost under the wing created from cold fuel in the tanks.

 

[moxiepilot]

thanks mini - i knew i read it somewhere but couldn't think of the resource. my reg reading has been more focused on endorsements lately the cfi initial sure blows sometimes.

 

[NYCPilot]

In the winter time, the early morning flights always had frost coating the top of the 172's wings and elevator. This was mostly due to the planes sitting in the shaded area of the ramp. We brushed off as much as possible with a broom while preheating the engine and just used a little more speed on rotation/climbout. The remainder of it sublimated pretty quickly after that.

 

[minitour]

thanks mini - i knew i read it somewhere but couldn't think of the resource. my reg reading has been more focused on endorsements lately the cfi initial sure blows sometimes.

Not a problem. Good luck with the CFI. I'm torn between the initial CFI (which was my -II) and the Instrument as to which was more rewarding checkride. Both require a ton of work.

Keep readin' up on the endorsements. If you know 'em cold and aerodynamics, your oral should be a snap. I've been studying for the ATP/DX written lately so 135 regs are on my mind a lot.

Let me know how the CFI goes!

-mini

 

[MauleSkinner]

91.527 allows you to polish frost as well...on your large or turbine powered multiengine 172

Check out the NTSB Advisory that came out in the aftermath of the Challenger crash in Montrose last winter at http://www.ntsb.gov/Pressrel/2004/041229.htm

Fly safe!

David

 

[snowbear]

Your CFI sounds well intentioned, but attempting to fly with anything on the wings or lifting body of an aircraft has killed far to many folks.

Some seem to advocate that you become a test pilot by polishing the surface then "adding a few knots to your rotation speed". Call any manufacturer in the world and ask them how much speed you add for ice and they will laugh you off the phone line. They did not test for, nor do they advocate taking off with anything other than a clean wing. Some will specifically allow ice on the fuel tanks (lower wing surface only) but this is generally on very powerful airplanes, the let is never for a lifting surface and is talked about at length in the aircraft operating maunual. Ice is deceptively heavy. If you polish the surface do you have any idea what the residual ice weighs? Are you sure you got it off the hinges and moving surfaces? How about the top of a T tailed airplane? Can you even see whats up there? Even if polished to a mirror like shine the ice surface will have thousands of tiny imperfections in it that has the capability to hamper or destroy lift. You may leave ground effect at your own peril.

Look to Canada, or any of the Northern European countries. All have a "clean wing" regulation. They have great experience with winter weather conditions and they all realized a long time ago that ice on wings is bad.

Please take the time to clean your airplane. The life you save may be your own.

 

[Almerick07]

Find a new CFI....when you polish that frost do you know exactly how much it weighs or how much surface area it adds, until you know those you cant know how much to increase your rotation speed by. If this is standard operating procedure for this guy who knows what else he does...intentionally or not.

 

[flydrummer]

I haven't started my training yet but something like that seems to be a common sense thing. Even though the FAR's allow you to polish the ice why would you want to take even the slightest of chances? If it were me I think I'd have to re-evaluate my CFI before doing any more training with him.

 

[English]

Polishing the ice....great! Now I have more duties I can assign to my copilot, along with polishing the wings, nacelles, etc.

J/K G!

 

[Almerick07]

It is safe only if immediately after polishing the wings you polish your shoes too.

 

[pilothouston123]

Old rule... Polish frost smooth
New rule... No frost on wings

hmmmm makes sence to me... rather be on the ground cleaning ice off wings than in the air wishing i would have cleand off wings

 

[MauleSkinner]

rather be on the ground cleaning ice off wings than in the air wishing i would have cleand off wings

You obviously haven't been to some of the places I have

 

[9GClub]

Empennage: CHECK
Wheel chocks: REMOVE
Wing frost: POLISH SMOOTH
Fuel selector: SCREW IT
ELT: ON/TRANSMIT

 

[Singlecoil]

Well, half of the posters on here would have been fired at some of the places I have worked. The ops manual says "polished smooth" and so do the regs. You run in and say you can't fly today because you can't remove the frost (no hangar, no de-ice available). You are fired.

This technique is SOP for flying in western Alaska.

The original question was about a general aviation trainer, not a friggin' CL-65. Polish it and go fly.