"The engine didn't explode"

Ask the A&Ps

Mike, Paul, and Colleen sludge through oil pumps that lose prime, skipping an oil filter change, and using the right oil in this Texas tea-themed episode. Email [e-mail] for a chance to get on the show.

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Full notes below:

Mike has a Cessna Bird Dog with an oil pump that isn’t cooperating. When he lets the airplane sit for a month or more, he doesn’t have oil pressure on the first start up. He’s conceived a workaround of pumping oil by hand into the engine and turning the prop backwards. Paul and Mike both describe having experienced this issue with Continentals. Mike said that Continental told him to prime the pump by removing the top spark plugs and pressurizing the case with shop air while you move the starter. Paul said they will unscrew the oil filter, fill it with oil, and then put it back on.

Cameron is trying to protect the Aeronca that’s been in his family for decades. He thinks using thinner oil sounds good because its viscosity helps after not starting for a long time, but the thicker W100 might better protect? He flies mostly in the winter, but he preheats. Mike thinks his strategy to use W100 when it’s warm and multiweight is good for colder temps. Paul likes multiviscocity so he doesn’t have to worry about temperatures.

Chuck is an A&P with another job, and he’s considering maintenance side hustles. He’s thinking of offering aircraft weighing services. He can either defuel aircraft or completely fill the tanks prior to going on the scales. Advisory circular 43-13 is unclear about which approach is better. Paul has always thought it strange that proper weighing procedures are in the POH, and not the service manual. That’s the first place to check, and the procedure that should be followed first. If there’s no procedure you go to the AC. He finds that most airplanes must be de-fueled first. Mike says to use FAR 43.13(a), which says that the mechanic must use the procedures in the maintenance manual, or acceptable practices and techniques. The AC has a note at the beginning saying that it’s only to be used if the manufacturer doesn’t have a process. But given that the procedure is in the POH, and not the maintenance manual, Mike suggests Chuck can pick and choose the way he weighs the airplane.

Jared is looking for a more permanent oil filter solution. First he wonders if he can skip changing the filter when changing the oil, in part because they were hard to get at one point. Paul said the only time it’s required to change the filter is during annual, when the IA is required to inspect it. Mike said he would like to inspect the filter as often as possible. He considers it the most important thing to do to monitor engine condition. Although people have taken their filters beyond 100 hours, there is oil analysis data showing that it’s a bad idea. The hosts then discuss reusable oil filters. Mike changed to reusable filters prior to Oshkosh, and has been initially pleased with the results. The Challenger filter comes off, the filter element comes out of the can, and the filter then washed. He was astonished by what came out of the filter because it’s easier to see what comes out after washing versus having to see what’s in the pleats of a filter.