In Spring, A Pilot's Fancy Turns To, Well, You Know...

March 2021

Last October, we published an Avemco PIREP entitled “READ THIS BEFORE YOUR NEXT FLIGHT that had several suggestions for how to make sure you were ready to climb back into the cockpit after COVID put a crimp in your flying. Those tips are still valid for anyone who is raring to go after having had their flying curtailed or cut off entirely over this past winter. But before you blast off on the first nice spring day, let’s talk about your airplane. After all, even a simple airplane is a complex piece of machinery, so some things need to be considered before you yell, “Clear prop!” for the first time.



Let’s start with the thing that makes your engine start. Make sure your battery is fully charged and in good condition. The first start after a long winter’s nap can put a heavy demand on your battery. And it may take some additional cranking to wake up your engine.


If possible, remove your battery from the plane and use a slow-trickle charger. Slow charging has more chance of recovering a discharged battery. Just as important, rapid charging can cause damage by delaminating the cell plates.



If you hangar your plane there may not be a lot of condensation in the tanks, but any water is bad, and condensation can form any time the temperature is below the dew point. Sump the tanks a few times to be sure. And rock the plane back and forth between sumps. If you have a bladder tank and the bottom has rippled, you’ll need to take some extra measures to make sure all the water is removed. Some tests have shown that more than a quart of water could be trapped in those ripples.


If you use 100LL, the fuel should still be good for at least a year without forming gum. Autogas, on the other hand, is usually good for about six months of inactivity. And if it contains ethanol, as much of the auto fuel does these days, it could be more problematic.



We’re not going to address a pickled engine, here. We will assume that if you used storage oil and desiccant plugs last fall, you know what to do. But many - perhaps most – pilots don’t pickle their engine over the winter. Hopefully, you changed your oil before the winter. Regardless, even though oil that has sat in your crankcase doesn’t wear out, it does become contaminated with small particles of dirt, metal, and unburned fuel and acid that form while the plane is sitting. Over time, the acid can play havoc with your cam, lifters, and other surfaces. When you first start your engine, this rust will act as a rubbing compound. That’s why it’s so important to change your oil before winter inactivity. Coating your engine with fresh clean oil is the most important thing you can do before putting the plane away for the winter.


That’s also why a gentle first-startup is so important in the spring. Let your engine idle at low RPM until the temp is well into the green arc. Then make sure the temp reaches 180°F when you fly to boil off any water.



Walk Around

The first walk around of the season is even more important than usual because more stuff could

have happened as the plane sat for so long. Birds, animals, and insects all love an airplane that has been sitting. Have a good look under the cowling, in the pitot tube, and at the static vents.


If you see any evidence of insect debris in the pitot and static vents, it’s not enough just to wipe it off. Some insects breed in the pipe runs. Best to have your A&P check the whole line for obstructions.


Your tires have almost certainly lost air or at least had their air condensed over a winter of doing nothing but sitting in the cold. And what about the brakes? Don’t just give them a cursory glance. Make sure the brakes haven’t seized up over the winter.


Grease and Lube

If the plane has been outside all winter, check all control surfaces for movement. Water can creep into the wheel bearings so carefully inspect and re-pack them if necessary. If you have a variable pitch prop, make sure it has a full oil supply by repeatedly cycling the pitch during your run-up.


Last and Most important: Go Have Some Fun

That’s what flying is all about. And that’s why it’s crucial to make sure that your mechanical steed is in just as good condition as you are. The less that can go wrong, the less you have to worry about and more you can turn your attention to the pure joy of flying.


We’d love to know what you think of this PIREP and whether you have some post-hibernation tips for our readers? Please email us at [email protected] and let us know.


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