Go fly the aircraft 30-40 hours before the annual?
I personally try to adhere to the 50 hours or 4 month limit, whichever occurs first. I'm not sure there's any particularly good science behind the latter, but I try to fly enough that I'm at least 25+ hours on the oil so it doesn't feel too wasteful.
Yes. A year in the sump is enough.
Actually it’s not at all. It’s owner discretion item.
Technically, an oil CHANGE is not required, but part 43 does require inspecting screens and sump drain plugs at annual/100hr:
So you could put the old oil back in. At that point, I'd just as soon change it.
Exactly. I don’t like picking nits, but some times I can’t resist.
FWIW: the 4 month limit is based on two issues. One, any combustion by-product in the oil will breakdown into acidic elements which is why certain oil additive packages are alkaline based. Unfortunately, over time those additives are consumed or neutralized which allows the acidic particles to attack metal surfaces. The 2nd issue is internal corrosion prevention as a lack of operation can leave internal metal surfaces exposed to the atmosphere. For reference, the flyable storage recommendations are one flight hour per 30 days which also takes into account the 4-month oil change recommendation. So in some cases, the calendar oil change limit can actually be more important than the hour limit. For example, if you run unleaded fuel in your Lycoming you can extend the hour limit to 50/100 hrs but it still keeps the 4 month limit.
If I'm running an engine dehydrator, does that change the math significantly? I'm deploying in about a month so the plane will sit for maybe six months. She has fresh oil (just changed it a couple of days ago). I'm hoping that maybe dessicant spark plugs and the engine dehydrator (Black Max) will minimize engine corrosion. The only other alternative is to have someone else fly her intermittently, and that gives me the heebie-jeebies.
Not really. Perhaps look over the full recommendations below for more options?
