Early on during flight training, we learn that wings will not develop lift if they have frost on them. Frost contamination disrupts the airflow over the wing, increases drag, and alters the airplane’s flight characteristics.
Let’s review two examples that illustrate the effect of airflow disruption.
Insect and bug contamination of the laminar flow wing’s smooth leading edge caused another airflow disruption, also increasing the airplane’s stall speed. Wiping the leading edge clean after every flight resolved the issue.
If a few bugs or a strip of sandpaper can affect wing aerodynamics and stall characteristics to such a degree, imagine what an entire wing covered in frost might do—and what it might not.
So, how do you prevent or remove frost contamination?
If possible, warming the airplane up in a hangar is ideal. If that’s not an option, place the airplane in a sunny location and wait for the frost to melt.
Some pilots polish the frost smooth with a broom or a rope or strip of carpet moved back and forth with a seesaw motion with the help of another person. Note, this procedure is prohibited by FAR Part 91 Subpart F for large airplanes. Although the regulation does not specifically address small airplanes, I do not recommend it. Wing covers are a better and common alternative to prevent frost from accumulating on the wings. To remove frost, you can use a deicing fluid called TKS.
TKS fluid is approved by the FAA and all airframe manufacturers. It is available at most FBOs in wintry climates. However, it is expensive. If you’re flying a lot in the wintertime, TKS fluid is a good investment and it can be purchased for less through aviation supply companies.
Be careful what you use on the airplane’s windshield and windows. Ammonia and other household chemicals or household deicing agents will create a permanent haze in the plastic. Also, the FAA prohibits use of automobile windshield washer fluid.