by David J Fill II @davidfill
All of us are probably familiar with FAR Part 43 that talks about maintenance tasks an owner can perform without the direct supervision and sign-off of an A&P Mechanic. Of the 32 tasks outline in this part of the regulations oil changes are absolutely the task you as an owner should be doing whenever possible.
I can certainly understand that like many car owners, airplane owners may not have the desire to attempt something like this, the inclination to get dirty, or even the time to mess with something like an oil change. Of these 32 items the oil change gives you an opportunity to thoroughly check over what is arguably the single most important part of your aircraft.
Lets look at this from a couple of different perspectives. From a cost savings perspective an owner performed oil change can save you a ton of money. A case of Aeroshell oil runs about $75.00 and an oil filter is about $15. If you have ever changed oil on one of your vehicles you probably have everything that is needed as far as basic tools already available. The three exceptions would be safety wire pliers ($20 for a decent pair), safety wire (about $7), and an oil filter cutting tool ($50).
Not counting your time your first oil change will run you about $167 in just materials assuming your have one of the larger Lycoming or Continental engines that will use all 12 quarts of oil – if not then your oil change will cost even less. Future oil changes will run you just the cost of oil and filter. Most shops charge about this much for a case of oil never mind the filter, and one or two hours of labor depending on the shop and their rates you will likely be paying in the range of $200-$350 for a simple oil change.
Looking at an oil changes from a safety perspective it provides an opportunity for you to closely look over your engine, associated accessories, and everything else under the cowling. Most likely the engine and inside the cowling doesn’t get much more that a cursory peek under a flashlight beam through an access panel or oil fill door during a preflight inspection in between annual inspections.
I have never done an oil change on any of my airplanes where I did not find something that needed attention. It could be something as simple as engine baffling that is wearing and needs to be noted for the next annual inspection to a decent sized exhaust leak that I discovered due to the heat discoloration on one cylinder head. Neither is likely to make the airplane fall out of the sky on the next flight but by noting these items and dealing with the exhaust leak immediately I was able to solve a problem that could have turned into a much bigger problem and larger expense down the road.
Whether you fly your airplane 10 hours a year or 500 hours a year things do break and do leak sometimes for no apparent reason. Look for quick-drains leaking, discoloration or burning due to exhaust leaks, evidence of insect or bird nests, chafing wires or hoses, cracked or brittle fuel, oil, or hydraulic lines, seeping gaskets, and loose fasteners.
I would recommend that your first attempt at an oil change should be under the watchful eye of an A&P Mechanic or trusted and experienced fellow aircraft owner. Keep in mind that that fellow aircraft owner legally can’t perform the work on your aircraft – you as the owner must do the work and sign it off in the logs – but he can guide you along and provide helpful tips that may make the job a little easier.
How long an oil change takes your first time around depends a lot on your mechanical ability, your particular model of aircraft – mainly how tight the engine and accessories are crammed together which may make access to the filter a bit of a challenge, and cowl configuration. After years of experience I have the process down to about 30 minutes per engine on my airplane.
While we are on the topic of oil – I’m a huge believer in oil analysis. I use Blackstone Labs and have used them for many years although there are many other companies out there that that provide similar services. Oil analysis runs about $25 or so every oil change.
If you are going to do oil analysis you need to do it each and every time. The purpose is developing trend data to show when something is in the process of or has already gone wrong. An occasional analysis once a year or every other oil change is not the way to gather valid trend data.
Like all things in aviation there is a preferred way of catching a valid sample. The engine and oil should be warm from a 30-plus minute flight its important that the warm-up be done in flight rather than idling on the ramp. Trying to warm up an engine and burn off the moisture that is in the engine oil will not happen correctly while on the ground. Most mechanics agree that engine oil should be warm anyways when draining so this should be part of your normal routine anyways.
After your warm-up flight by time you have all your tools and materials assembled and the cowl opened up the engine will probably have cooled enough not to burn your hand when you turn the quick drain or drain plug. Start draining the oil and grab a sample of the oil a few seconds into the drain process.
I wont discuss in detail how to cut open and examine an oil filter but this is very important to see if your engine is “making metal.” There are plenty of YouTube videos out there with good instructions or have your mechanic show you the correct way and what exactly you should be looking for. This is something you absolutely must do every time. Some rushed shops may skip this part and some owners who don’t want to get dirty may shy away from this task, but it’s simply too good of a chance to spot major engine trouble to skip.
Ready for the single hardest part of an oil change? Putting it all back together – mainly the safety wiring of the filter and/or drain plug. There is a correct way to safety wire and I guarantee your first few times will look nothing like the tight, neat and professional twists of the old safety wire you cut off when you started. Practice and get it right. Losing all of your engine oil out of a missing drain plug or oil filter that rattled and vibrated off in flight is probably not on your bucket list.
When everything is completed, engine filled with the proper amount and grade of fresh oil, and put back together check one more time for forgotten tools, rags, or anything out of place. It’s helpful to have another person take a quick look whether that is a hangar neighbor or even a spouse that happens to be around. Do a good engine run-up on the ground and then shut down and check for leaks. Don’t forget to fill out an appropriate log entry in the aircraft maintenance logs detailing what work was completed along with your signature and certificate type and number.
Congrats you just saved a decent amount of money and got a chance to examine your engine and airplane more closely than most owners will ever bother to in their entire flying career. I know Id rather spend that money flying rather than hand it over to the local shop.
David Fill – @davidfill – is a Commercial Pilot, Aviation Podcaster, and Aircraft Broker based in the Washington D.C. area. He flies a King Air for a Part 91 corporate flight department and owns a light twin used for family and personal business transportation.