February 15, 2026

“Is this like pulling a mattress tag off?”

54 minutes

What exactly should we be looking for in our cylinders? Plus torque tales, making TBO, and overzealous manufacturers.

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Full show notes below:

Jared asks what he should be looking for with his borescope. He’s seen bad valves and what that looks like, but he’s also hoping to see what bad scoring and other things. Colleen stresses to focus on what goes wrong with a cylinder, and being able to identify those attributes. Things like broken rings, piston pins, detonation signature, etc are identifiable, and can be examined. Paul said rust is always something to look for, but most cylinders have some. Knowing how much and why it’s there is what matters. Mike said rust would cause him to consider the camshaft on an airplane in a pre-buy situation, for example.

Chad has a new Cessna turbo 206. He wants to be sure to get to TBO and then some. Paul said the one thing he needs to do is fly as often as possible. He is flying 400 hours a year, which the hosts love. He asks if he

can fly a maximum continuous power, and the hosts agree that he can, so long as his cylinder head temperatures are within spec. The book tells Chad to lean to peak turbine inlet temperature, and not to run lean of peak. He wants to know if this is a real threat or a hollow one. Once again, the hosts agree that it’s a hollow threat, and that he should operate lean of peak if he can. They also discuss the myth of turbo cooldowns. Mike said George Braly instrumented a turbo and found that it actually got hotter as it sat on the ramp “cooling down.”

Serrhel is sick of the Continental maintenance schedule. He has a Cirrus that is under warranty, and he’s required to do the maintenance as scheduled. At 300 hours an injector cleaning was required, and only a few

months later, the injectors had to be cleaned again during the annual. Cirrus and Continental required it, even after some pushback. Paul said manufacturers don’t buy into the probability of maintenance induced failures or in the concept of reliability centered maintenance. The discuss the reasons why manufacturers think this way, and Mike said a conversation with a factory representative taught him that they basically don’t trust GA pilots and owners to maintain aircraft at a high level.

Patrick is throwing down a challenge to Paul. He said Paul always stresses that when tightening case through-bolts, you torque simultaneously with torque wrenches on both sides at the same time. Old Continental videos say the same, but the video shows the technicians only torquing on one side at a time. Despite the guidance, Paul said it doesn’t make sense to put a torque wrench on both sides at the same time. Mike said if you put a torque wrench on both sides, one side will be torqued dry and hit the pre-load spec too early. Mike and Paul then get into a debate about how the logbook entry should be made when if you decide not to follow Continental’s advice. Patrick further mentions that the Continental service manual doesn’t say it should be simultaneously.

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