Changing the Oil

I changed the oil in the Beech Sierra on a hot, humid morning in July … and found it’s a great way to enjoy personal aviation.

FAR 43 Appendix A paragraph (c) tells us what “preventive maintenance” persons not licensed as mechanics (and not so supervised) can legally do to airplanes — but it doesn’t tell you such minor tasks can be fun. Even someone as mechanically ungifted as I can safely and enjoyably do the “little things” like change the oil. It’s easy:

  1. ASSEMBLE YOUR TOOLS. Depending on the airplane type, you may need to remove the cowling (allowable under Part 43 so long as the design doesn’t require you remove a propeller or disconnect any flight controls). A screwdriver will usually do it. You’ll need something to catch the oil as you drain it — I found a pair of gallon milk jugs work great. Label your containers as “used oil” (it is *not* waste oil, which signifies non-recyclable, hazardous material requiring special disposal). Plus, afterward they’re easy to carry when you take used oil to the recycler’s. You’ll need a length of hose to carry the oil from the drain pan to your receptacles, and a wrench to loosen the drain plug if your engine is not equipped with a “quick drain“. You’ll probably want an old blanket or a come-along to cushion yourself from the hangar floor or the ramp. A pair of thick gloves helps, too, because the engine should be hot when you change the oil. Of course you’ll need replacement oil and a funnel to get it in the filler, not all over the top of the engine. And don’t forget rags or paper towelslots of paper towels, because changing the oil can get messy.
  2. WARM UP THE OIL. Go fly for a few minutes, or schedule time after a planned flight to change the oil. In my case, it had been well above 90 degrees for days (not getting below the mid-70s at night), so I cheated and changed the oil in the “cool” of the morning without warming the engine first. The cooler the oil, the less likely you are to get every last drop. The hotter the oil, the faster and more complete the process will be.
  3. POSITION YOUR FIRST MILK JUG (or equivalent) with the hose stuck in its end, and open the drain pan. The Sierra, like most airplanes, has a “quick drain” on the bottom of the oil sump, allowing me to simply “push and twist,” and it locks in an open position. I stuck the “other” end of the hose over the end of the quick drain before opening it up, avoiding a nasty, environmentally unfriendly oil spill on the ramp.
  4. THE OIL FILTER. Use the screwdriver to carefully punch a hole in the filter’s top (or if installed horizontally, its “up” end as installed) to help oil drain out of the filter and into the sump before you remove the filter later on. If the filter is horizontally installed, be sure to cover the hole before turning the filter. Another method better suited to horizontal installations includes placing a channel that runs between the filter and gasket down to your used oil receptacle. As you loosen the filter, residual oil will run down the channel to the receptacle … instead of all over your engine! This method works quite well, but it’s also more difficult to describe (ask your mechanic).

    Note: If you’re planning to cut open the filter later to inspect it for metal contamination (a sign of trouble in the engine), be careful not to create shards of metal that might “look” like oil contamination.

    ***Caution: Oil will deteriorate rubber lines and engine mounts. Use caution to ensure that no oil makes contact with a rubber part.

  5. NOW, PIDDLE AROUND the airplane a while as the oil drains. Clean something. Take a good look at the engine compartment, or the landing gear, or the control surfaces. Even if you don’t have a good idea of what you’re looking at, familiarization will help you spot anomalies next time — and you can ask your mechanic about those. Sit in the pilot’s seat and practice your emergency checklists or read the Pilot’s Operating Handbook. Watch the traffic come and go. Changing the oil can be a much more social enterprise than you might think. I saw an ultralight buzz by in the diffuse, hazy dawn; talked to the pilot of a turbocharged Bonanza (I’ve got a “thing” for the B36TC) who flew in to visit some friends; watched a corporate twin Cessna touch down, delivering construction engineers for a brief business meeting before taking off again; and said “Hi” to the local instructor and his student as they prepped the FBO’s Skyhawk for practice toward an instrument rating … all in the brief while the oil was draining.
  6. COLLECT A SAMPLE. Somewhere in mid-flow I pulled the hose out of the milk jug momentarily, filling a small sample jar to be sent away for oil analysis. Then I continued draining into the second milk jug.
  7. WHEN THE OIL FLOW STOPS, replace the filter as necessary (the Sierra does not have an external oil filter). Dip a finger into the clean oil and rub a very small amount on the filter gasket before screwing it on, then close up the oil sump and wipe clean the drain plug — you’ll want to check that it stays clean after you add oil, to know it’s completely closed. Do *NOT* over-tighten the drain plug; you don’t want to strip it out … that would be very bad.

    ***Important: For many installations, your oil filter should be secured with safety wire. This is easiest with a special tool and a little special knowledge. The first time you do this, you should solicit the aid of a mechanic … and ask them where to get the tool.

  8. ADD OIL to the level recommended by the manufacturer, or from your own experience. Extra oil will be blown out your exhaust — further polluting the environment while wasting your money.
  9. CLOSE THINGS UP and double-check that everything’s clean and secure, then get all your oil-changing gear away from the engine, and secure.
  10. TEST-RUN THE ENGINE. Pay special attention to the oil pressure and temperature gauges. Run the engine for a minute or two (since it was warm before you started, it shouldn’t take long to register “in the green.“)
  11. CHECK YOUR WORK. Shut the engine down and crawl back under the cowling. Check the drain plug or quick drain for leaks. You cleaned it before the test-run; it should still be clean now. Re-secure the plug or drain if it showed any drops of oil, being careful to catch any spill while you tighten the plug.
  12. LOG YOUR WORK. Make an entry in the airplane’s engine logbook indicating the date, the fact that you changed the oil (and filter), and the type of oil and filter used. End the entry with the statement that you’ve “returned the airplane to service” and sign your name.
  13. YOU’RE DONE. Pick everything up and take your oil to be properly recycled.

BOTTOM LINE: My fortunes have changed, and I had to get out of my partnership in the Sierra — scarcely two months after I got in. But that quiet, hazy morning will be one of my favorite memories of airplane ownership. Know your regs — specifically, FAR 43 Appendix A [scroll down to paragraph (c) “preventive maintenance” — anything else must be performed by or adequately supervised by an appropriately licensed mechanic]. You don’t have to be a licensed mechanic to save money and have fun taking care of an airplane!