Guest Editorial: Winterizing Your Aircraft

Picture: Courtesy & Copyright Tara Terry

Winterizing Your Aircraft -Tips From A Pro


Picture: Courtesy & Copyright: Tara Terry

Written by Eric Ellison — With the return of the colder weather, airplanes tend to get less utilization. It’s important to think about how much you intend to fly between November and March, and winterize your airplane accordingly. A little prep can greatly extend the useful life and help keep maintenance costs down.

Starting with the outside of the aircraft, a thorough soap and water wash and full wax will help prevent the build up of corrosive pollutants from the atmosphere. The wax will help prevent paint oxidation from UV exposure and also mitigate the growth of moss, which is a common problem in the Northwest.

To protect the interior plastics from UV damage, a reflective sun shield or external window cover is a good choice. If an external window cover is chosen, it must be installed tight so that it cannot work against the plastic windows. If installed too loosely, dirt can accumulate under the cover and act as an abrasive.

If possible, make sure the aircraft is parked with the nose within 90 degrees to the prevailing wind and install control locks. Wind on the nose will not deflect the flight controls like wind from behind the aircraft. Control systems can be easily damaged if control surfaces are allowed unrestricted motion with wind on the tail.

Moss and mildew can be a problem on the interior of the aircraft as well as the exterior, so measures should be taken to keep the interior as dry as possible. If the airplane is to be stored outside, like most float-planes, the interior should be checked for signs of window leakage. Make the check after a rain and feel the side panels and floor covering for wetness.


Picture: Courtesy & Copyright Tara Terry

In Cessna’s, it’s not uncommon for a side window to leak and for the water to run forward along the floor, making it appear to be a windshield problem. Sealing up any window leaks before the rainy season could make a significant difference.

Remove as much of the interior as you can and store it in a dry place. Just taking out the seats and the floor covering is a good step if the airplane will be sitting outside. If the aircraft is near a power source, consider using a boat style dehumidifier such as the “Electric Air-Dryr 1000” available from Fisheries Supply. This product has no moving parts, so it’s a no-spark device.

If the airplane will sit without running for 2 weeks or more, it’s a good idea to disconnect or remove the battery. Many aircraft will have some small parasitic load that can drain a battery over time. Even the small current created by a parasitic load can accelerate corrosion in the air-frame. If power is available at your moorage, a small battery tender will keep the battery healthy during periods of inactivity. If no power is available, consider taking the battery home and keeping it on a tender until needed again.

100LL is a relatively stable fuel, and doesn’t absorb water like the ethanol in car gas. The tanks should be topped off so there is no room for condensation to form at the top of the tank. On deHavilland Beavers, it’s a good idea to completely drain the tip tanks and leave the sump drains open to drain any water that might make its way in.

The engine should be run at least an hour at operating temperature every two weeks. If the interval must be longer, measures should be taken. An oil change before any period of inactivity is a good idea, as used engine oil contains corrosive acids. If the engine won’t be run for several months, have your mechanic drain the oil and add a preservative oil, such as Aeroshell 2F.

Do not move the propeller during a period of engine inactivity, as it will wipe the oil coating off the internal components of the engine. Cylinder dehydrating, or “Protek” plugs contain a silica gel that will help protect the cylinders. They start blue and turn pink as they absorb moisture. A bag of silica gel can be placed in the intake and exhaust and taped over as well. Just make sure there is a streamer attached, so they’re not missed during De-preservation!

Eric Ellison is the Director of Maintenance at Kenmore Air. He is an A&P IA and a Private Pilot. Eric’s education includes a Bachelor’s degree from ERAU in Prescott, Arizona and an MBA from Presidio. Originally from Anchorage, Alaska, Eric has worked at Kenmore Air since 2002. With 25 aircraft in operation, Kenmore Air is among the best-known and most respected seaplane operations in the world. Check them out via

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