By Lisa Turner, EAA Lifetime 509911
This piece originally ran in Lisa’s Airworthy column in the May 2023 issue of EAA Sport Aviation magazine.
“What a long winter this was,” Kate said as they drove through the gate onto the access road behind the hangars. “Finally, the snow is melting. Look at that!”
Rick looked up at the roofing. Water was streaming down onto the ramp as the mid-morning sun heated the metal.
“It’s supposed to hit 60 degrees today,” he said, as if it had never happened before.
They pulled up to the hangar and opened the track doors. The old doors squealed in protest.
“I love that sound,” Kate said. “I can’t wait to get in the air.”
“I did a bad thing,” Rick said, looking ruefully at Kate.
“What bad thing?”
“I didn’t put the airplane away properly last year,” he said. “No oil change, no preservative, no covers, no fresh fuel, nothing. I just parked it in the corner of the hangar.”
“Uh-oh.”
When they looked at the airplane, they knew they wouldn’t be flying soon. One tire was flat, nesting material oozed from the cowling and the exhaust, and droppings covered the windshield.
“You did take the battery out, right?” Kate asked.
She didn’t need an answer when she looked at Rick’s expression.
* * *
If you live in northern climes, love to fly, and enjoy winter, you may be the hardy soul with an airplane on skis. But, if you’re like the rest of us, you probably put your aircraft into storage for the winter. Or did you?
While there is plenty of advice on how to store your airplane, there isn’t much information about what to do if you never followed the procedures for storage. The assumption is that you did follow procedures. In that case, you simply reverse the steps. What if there are no steps to reverse?
If this happened to you, don’t beat yourself up over it. You already know an airplane’s systems longevity will go up with proper storage. Pulling it out and flying after not following storage procedures can deliver an assortment of problems. Many pilots have done exactly this without incident. But the chances of something failing are high without the checks I am about to talk about.
What you need to look at and inspect will vary according to the storage conditions for your airplane. If you put it into a heated space, like a garage or a hangar, it will fare much better than if you left it outside. The other differentiator will be the building tightness. Most hangars will not keep mice and insects out of your airplane.
Here are the top traps and some suggestions for handling them.
Trap 1. You didn’t prepare the engine for storage. This would have been done according to the aircraft service and maintenance manuals.
What to do. Pull out the aircraft engine service and/or maintenance manual for the engine you have. Read what it says about putting it into storage and taking it out of storage. See what it says about simply not flying in a while. Engine manufacturers typically give the owner a thorough and detailed procedure for storage, and the length of time they consider okay for doing nothing. For example, Continental says, “Temporary storage is considered 30-90 days, and indefinite storage is considered to be 90 days or more ….”
The time your airplane sits idle makes a difference. If it’s been over 90 days, detailed inspections, especially for corrosion, will be most important. You will want to find out (from the engine manufacturer) what procedures to use prior to starting.
Have a radial engine? A survey of vintage aircraft restoration shops confirmed what we know — that corrosion is what really does the damage. When they start an engine that’s been sitting without any preservation, they use an oil additive the day before start (plugs out, cylinder spray-down). Get informed advice if you’re in this situation.
Have a two-stroke engine? See Trap 4.
Trap 2. You didn’t remove and trickle-charge the battery.
What to do. Good aircraft batteries are expensive. During storage, the battery should come out of the airplane, be inspected, and then hooked up to a trickle charger. The latest smart chargers are the best, and they are inexpensive compared to new batteries.
Depending on how long the airplane sat, the battery may be just fine. But don’t assume it is, even if the airplane started. Borrow a load tester and check it.
Lead-acid batteries can be tested with a hygrometer. Lead-acid batteries are economical, but they do not suffer long stretches of storage well. Storage without a maintenance trickle charge can degrade the battery and its longevity in a few short months.
Ni-Cad, Ni-MH, Li-ion, Li-poly, and other sealed batteries are durable and reliable as long as you follow manufacturer instructions for storage and charging.
Check compartment venting system tubes and attachments, and look for and clean any corrosion you find on and around the battery.
Trap 3. You didn’t seal up the airplane against creatures and dirt.
What to do. Consider the storage conditions. If mice, insects, and other freeloaders can get through the door (mice can squeeze through a quarter-inch opening), then assume they have taken up residence in your airplane.
Use a powerful flashlight for your inspections, and if your airplane is fabric-covered, a suction cup to check for chewed-through lacing in panels. A borescope is handy, too.
Even if your aircraft is inside a hangar, dust and debris will find it. I’m not saying you should cover it when it’s inside, but if the length of time is substantial, a cover will protect the finish from dust and dirt layers, as well as droppings from any nesting birds in the rafters. It seems as if they pick exactly the spot right over your airplane or your workbench.
Give your airplane a bath. Not only will it look better, it will be much easier to identify any problems. Have you noticed when you hand-wash something you find the tiny problems that escape you on walk-arounds?
Trap 4. You didn’t drain the automotive fuel from your light-sport, experimental amateur-built, or ultralight aircraft.
What to do. Over many months of sitting, autogas congeals. If left alone long enough, the fuel evaporates, leaving gum and lacquer. Pull out the engine manuals to determine how best to get things cleaned up and running again. It may involve a carburetor inspection/overhaul. The manufacturer will have the best advice. Follow the instructions for flushing the fuel tanks, if necessary.
Find out from your engine manufacturer if it’s okay to put a gasoline preservative in your automotive fuel. If permitted, it will extend the life of your fuel. You also want to fuel up with the highest quality autogas you can find. I choose high-octane, 100 percent ethanol-free.
If your engine also runs on 100LL — like many Rotax engines — consider switching as winter storage time approaches. A nice feature of aviation fuel is its durability over time. In the spring you can switch back to auto fuel.
Inspect all lines and change fuel filters. If the autogas has left a gummy mess, it will be critical to get everything cleaned up and free flowing again. Remember that fuel problems are high on the list of reasons engines quit.
Trap 5. You didn’t inspect the components that degrade with age.
What to do. Do you have a checklist for inspecting materials? These items could be rubber or plastic fuel lines, hydraulic lines, hoses, and cables. Over the winter, you may see an acceleration of wear on materials. Don’t assume they are in the same condition as they were when you put the airplane in the corner. The second law of thermodynamics says that entropy always increases with time. In other words, things go downhill.
Use a checklist to inspect the parts and pieces of systems, as you would do on an annual or a condition inspection. You’ll want to do this step even if you looked at everything before you put the airplane away properly. Assume that gremlins have visited your airplane while it was in storage.
If you’re flying year-round, lucky you! But you may find that time gaps creep in for travel or other reasons, and suddenly you realize you haven’t flown in months. So even though you don’t have to winterize your airplane, you should still do extra inspections if it’s been a while since you’ve flown. Make notes in your service paperwork for manufacturer recommendations on extended inactivity.
I have a practice of servicing all of my yard equipment in the fall. The tuneups and oil changes mean everything starts when I want them to in the spring. But airplanes are not lawn equipment. When you’re getting in the air, you need to have maximum reliability. If your airplane sits for a while, get the checklist out and go through everything in detail. When you need to put it away for over 90 days, pull out the manuals and store it per the book. A quick job? No. Peace of mind? Yes.
Lisa Turner, EAA Lifetime 509911, is a manufacturing engineer, A&P mechanic, EAA technical counselor and flight advisor, and former designated airworthiness representative. She built and flew a Pulsar XP and Kolb Mark III, and is researching her next homebuilt project. Lisa’s third book, Dream Take Flight, details her Pulsar flying adventures and life lessons. Write Lisa at Lisa@DreamTakeFlight.com and learn more at DreamTakeFlight.com.