HOW OFTEN SHOULD YOU CHANGE YOUR AIRPLANE'S OIL?

Recently I was talking to an engine rebuilder about oil change intervals for aircraft engines. He related an experience with a plane owner who was having him do an annual inspection on his aircraft. A problem came up when the mechanic listed an oil change as part of the inspection, even though the aircraft had been flown just 12 hours in the last 12 months.

- BEN VISSER

The owner insisted it did not need an oil change since the manufacturer recommends an oil change only every 50 hours. He completely disregarded the other part of the manufacturer's recommendation: "Every 50 hours or four months, whichever occurs first."There is no good answer for what the oil change interval should be for a super low-usage aircraft, like this one that is only flown 12 hours in a year. I would not expect this owner to change the oil every four hours. But going four years without an oil change will probably result in a ruined camshaft and other problems. The real problem here is that this is not a rare occurrence in general aviation.

The latest edition of Lycoming Service Letter 270 states that after the initial transition 50hour oil change, subsequent oil changes should be every 50 hours, but can be extended to 100 hours if unleaded fuel is used.