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If you plan to fly on a cold morning and there is frost on the plane, what needs to be done?

Do you have to remove the frost from the windows? wings? tail? fuselage?
How should you remove a thick layer of frost?
Can you rub the frost until it's smooth and take off?

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    $\begingroup$ ...on small planes, beyond a certain point (what I can knock out in 15-20 minutes with a spray bottle of de-ice solution) I usually roll my eyes, curse the weather, and go across the field to the coffee shop to wait until it gets warmer :-) $\endgroup$
    – voretaq7
    Dec 21 '13 at 2:39
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    $\begingroup$ Related: How NOT to handle frost on a plane! $\endgroup$
    – voretaq7
    Jan 10 '14 at 16:27
  • $\begingroup$ Polishing frost is a perfectly acceptable practice (regardless of FAR's). I remove frost from windows, broom the wings and tail surfaces - check the undersides. Polish the fuselage if your feeling energetic. Take-off at a higher airspeed than normal. $\endgroup$
    – fbynite
    Jan 11 '14 at 2:35
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    $\begingroup$ Large aircraft operators are prohibited under FAR 91 Subpart F from polishing frost smooth - they must remove all of it prior to takeoff. While light GA aircraft don't fall under this rule, it makes sense to comply with it. Our wings are just as susceptible to the reduction in lift and increase in drag caused by ice and frost. ref $\endgroup$
    – bovine
    Jan 16 '14 at 4:08
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You should definitely not attempt flight if there is frost on the windows that would affect visibility, or on any of the wings or flight control surfaces. Frost accumulation on such surfaces can reduce the lift generated by your wings, possibly causing a crash on takeoff.

According to the NTSB, frost the size of a grain of salt, distributed as sparsely as one per square centimeter over a wing's upper surface, can destroy enough lift to prevent a plane from taking off.

The cheapest solution is to try to re-position the plane on the ramp so that the sunlight has a chance to melt it away.

You can also temporarily move the plane into a heated hangar until it melts, or ask the FBO to do so for you. If the forecast is predicting a chance of such conditions the night before, you can usually call the FBO on the night before and ask them to move your plane into their hangar just for the night, in advance of your morning flight.

If you're really anxious to go, you can ask the FBO to apply a heated deicing solution to your plane, but be prepared to pay for it (it's priced by the gallon and the amount needed will depend on the size and amount of frost of your plane). Not all FBOs will have deicing capabilities, particularly if the region does not commonly experience such conditions.

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    $\begingroup$ I bring a small spray bottle of TKS fluid with me, including a few towels. Spray it on, wait a minute, then wipe off the snow/frost with a towel. You can clean up a 4-seater plane in 20 minutes or so. Do NOT use hot water, as that may re-freeze in a BAD place as later. I use TKS anti-ice fluid made by Davies - can get it in gallon jugs. $\endgroup$
    – Jason
    Dec 20 '13 at 18:33
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I don't know if you're in the US, but if so then by regulation you must remove it from all critical areas before flight, per 14 CFR 91.527:

§91.527 Operating in icing conditions.

(a) No pilot may take off an airplane that has frost, ice, or snow adhering to any propeller, windshield, stabilizing or control surface; to a powerplant installation; or to an airspeed, altimeter, rate of climb, or flight attitude instrument system or wing, except that takeoffs may be made with frost under the wing in the area of the fuel tanks if authorized by the FAA.

In practice, that really means removing it all, and I guess that other countries have similar rquirements. The NTSB has a detailed guide on ground icing where they say that it must be removed "by any means necessary" before flight. For light aircraft, the usual recommendation is to hangar the aircraft and let the frost melt off. But you need to ensure any moisture is completely removed before flying, otherwise it may re-freeze.

Larger transport aircraft (or any aircraft, in principle) are usually de-iced, which is a common sight at airports in winter. The FAA has an extremely detailed document if you're curious.

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    $\begingroup$ Just for the record, 91.527 is part of 14 CFR 91 Subpart F, which only applies to "Large and Turbine-Powered Multiengine Airplanes and Fractional Ownership Program Aircraft". While this doesn't apply to most light airplanes, it is a very good practice to follow to ensure a safe flight! $\endgroup$
    – Lnafziger
    Jan 16 '14 at 4:07
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Polishing the frost until smooth used to be a legally permitted way of handling the problem. The regs have changed, because a very small amount of frost, polished or not, can seriously affect your aircraft's performance. It must be removed! POLISHING THE FROST IS NO LONGER PERMITTED.

However, if the frost is not on control surfaces, say on the top of the fuselage, it is ok to fly with it on. (Unless of course you are flying a Piaggio or some other plane where the shape of the fuselage creates lift...)

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    $\begingroup$ Could you link to the reg? $\endgroup$
    – CGCampbell
    Dec 6 '14 at 18:07
  • $\begingroup$ See the answer above by Pondlife. $\endgroup$
    – Skip Miller
    Dec 6 '14 at 19:19
  • $\begingroup$ Pondlife's answer only applies to certain aircraft (though he doesn't note this, see Lnafziger's comment). Do you have a reference for other aircraft, such as a C172 operated under §91? $\endgroup$
    – J Walters
    Dec 23 '16 at 17:38
  • $\begingroup$ Sorry, I have been away for a while. far $\endgroup$
    – Skip Miller
    Jan 28 '17 at 21:39
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Of all the challenges in aviation, ice is probably the scariest, no matter the size of the airplane. It can ruin your day REAL fast if you don't deal with it properly. Bigger aircraft usually have better systems / support personnel to deal with it, but it still needs to be dealt with on smaller aircraft. If you're still on the ground, remove it completely. From every surface. Use deice fluid to get rid of it (or a heated hangar), and if the accumulation is such that it keeps returning quickly, anti-ice solution can work. But this level of icing should definitely factor into your No-Go decision.

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