Winter Maintenance

By Vic Syracuse, EAA Lifetime 180848

Many of you know my primary purpose in aviation is to keep the fun factor alive, especially from a safety and maintenance perspective, which can go hand in hand. A couple of years ago I wrote a column about off-season maintenance. I’ve been thinking that it needs to be at least a biennial column, at least from some of the things I am seeing on various aircraft.

I’ve seen many of our customers’ trips get canceled or interrupted by items that could have been caught with a little more focus on proactive maintenance. By the time you read this column, most of you in the Northern Hemisphere will be seeing fewer flying days, so perhaps I can inspire you to poke around in a few areas on your aircraft. It might just make your upcoming flying season more enjoyable.

Let’s start with oil changes. It could be that the current state of the economy is impacting the annual flying hours. Whatever the reason, I am seeing more and more customers returning to the shop for their condition inspection without having changed the oil or filter in the last year. Often, I hear the excuse that it was flown for only 25 hours.

First, both of those — not changing the oil in more than a year and infrequent flying — are bad for the health of the engine, especially with Lycoming engines. Most of the oil manufacturers recommend replacing the oil every four months regardless of the flight hours. If you have an oil filter, the recommended maximum flight hours is 50, regardless of the calendar time.

The oil has lots of combustion byproducts in it, which are corrosive. Just leaving the oil sitting in the engine compartment is a bad idea. Plus, the oil tends to drain off things, like the camshaft, which then gets abused during the next startup due to the lack of lubrication.

There are additives that can help diminish some of this wear, such as CamGuard and AVBLEND, but the best preventive is regular use. By regular use, I mean flying and bringing the oil temperature up to operating temp for at least 20-30 minutes.

Ground running the engine is horrible. Don’t do it! I’ve seen the components in the accessory case of Lycoming engines, such as magnetos, extremely rusted from engines that were only ground run over an extended period.

Changing the oil every four months at a minimum is cheap insurance. If you do it yourself, it can still be done for less than $100 in most places, which includes the oil, filter, and additive for most four-cylinder engines. Yes, $100 is still a lot of money, but current engine prices and overhauls are real eye-openers, too!

As many of you know, one of my hot buttons is intake gaskets and hoses. Those components of the engine are often overlooked and are the cause of many issues, from high cylinder head temperatures (CHTs) to hard starting. Recently, we had an RV-10 in the shop whose owner was complaining about high CHTs.

Most of the time we find that the owners only think they have high CHTs due to too many internet opinions they’ve researched. In this case, when I asked about the “high number,” I was told 460 degrees Fahrenheit on climb-out to 2,000 feet AGL. Yep, that is hot, and way too hot for an RV-10. Something was wrong, and clearly something had changed.

The customer stated that the higher temps started immediately after a complete panel upgrade. My initial thoughts were that it could be a configuration issue, or that something had been changed in the cooling when the new sensors were all installed. Nothing was discovered that could have impacted the cooling. However, I learned that the panel upgrade had taken almost eight months. I immediately looked at the intake gaskets and O-rings on the cold air induction tubes, and they were most definitely the culprits. They had dried out and were brittle and leaking. Changing all of them reduced the temps in climb-out by 60 degrees.

Most owners who perform their own maintenance seem intimidated by replacing the intake hoses, gaskets, and O-rings. It’s not that hard and usually takes only about 15-30 minutes per cylinder. I’ve highlighted them in my book and made a video or two about them to help owners. Those of you who have carbureted engines will notice harder starting issues as the gaskets and hoses begin to leak, as it is harder for the engine to suck the fuel up from the carb to the cylinder.

Other maintenance areas we see having a negative impact on the fun factor are the tires, brakes, and nose wheel break-out force. Yes, I know it can be a pain to remove the wheelpants, but I am also shocked at how many aircraft come to our shop with bald tires and brake pads worn down to the rivets.

One customer even mentioned this past week that his brakes were horrible. Yep, they were worn down past the rivet heads. I doubt there was much braking power at all, and no doubt it could have been risky if a quick stop was needed. We have deer running across the runway quite often. Even taxiing in a stiff crosswind can be challenging at times in non-steerable nose wheel aircraft like the RVs.

Spark plugs are another area that could use some more TLC from owners. Lead fouling, especially of the lower plugs, still tends to be a problem. The major cause of lead fouling stems from improper ground operations.

My recommendation is that immediately after the engine starts, your next move should be to the mixture control. The ground idle should be around 1000 rpm, and the exhaust gas temperatures should be around 1,000 degrees Fahrenheit. This should ensure that the lead in the fuel is properly vaporized. Otherwise, the lead tends to form little globules in the spark plugs that eventually short out the plug, causing misfires. These are usually discovered during the run-up right before you depart on your trip. This is also one of the reasons that I recommend checking the ignitions prior to shutting down. That way, if something is wrong, you can get it fixed before the next trip.

For those of you who install one magneto and one electronic ignition, I recommend installing the electronic ignition such that all the spark plugs for it are in the bottom location of the cylinders. The hotter spark from the electronic ignition seems to do a better job of preventing spark plug fouling. I also recommend replacing the electronic ignition spark plugs every 100 hours for those using the automotive-type spark plugs. The aviation spark plugs should be cleaned and gapped every 50 to 100 hours.

Don’t forget to check the air filter. For those of you who are using the K&N reusable filters, clean them at least every 100 hours, or sooner depending on the environment. In the southeast United States, every spring for about three weeks we have pollen so thick from the pine trees that some days it looks like green snowstorms. I clean the filter when that subsides.

The last item for off-season maintenance has to do with the external lights. For those of you who are flying during the winter season with shorter days, there’s a good chance you might fly after sunset. Be sure to check the position lights and landing lights. It’s really annoying to have enjoyed a nice sunset flight only to find the landing light doesn’t work when you come back to land.

It’s also about the time that you realize how much darker it is on the ground than it was at 2,000 feet staring at the sunset. Perhaps it is an age thing, but I sure feel like I can’t get enough lumens for those night landings anymore. For those of you who are aging, perhaps getting a new set of LED landing lights installed during the off-season would keep the nighttime fun factor alive.

Vic Syracuse, EAA Lifetime 180848, is a commercial pilot, A&P/IA mechanic, designated airworthiness representative, and EAA flight advisor and technical counselor. He has built 11 aircraft and has logged more than 10,000 hours in 74 different types. Vic founded Base Leg Aviation, has authored books on maintenance and prebuy inspections, and posts videos weekly on his YouTube channel. He also volunteers as a Young Eagles pilot.

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