"The airplane looks like it's having brain surgery"

Ask the A&Ps

Mike, Paul, and Colleen debate the difference between a bribe and incentive pricing, discuss how much carbon in the oil filter is too much, counsel an owner how to keep his alternator belt on, and reveal what's in their go-bags. Email [e-mail] for a chance to get on the show.

Full notes below:

Jim is finding a significant amount of carbon in his oil filter after oil changes on his Cessna 182. He wants to know if the carbon is a problem. Mike said the carbon itself isn’t a problem, but it’s indicative of something else that is worth tracking down. He said the oil is getting overheated, carbonizing it. It’s most likely from excessive blowby. They recommend compression checks and borescoping to see if he can find the culprit cylinder.

John flies a Mooney with an electronic ignition system, and he thinks the airplane is slower since the system was installed. Mike thinks it’s possible it wasn’t timed properly. They see it often because the electronic ignition system is timed differently than a traditional magneto. If the EGTs are up and CHTs are down, that's further confirmation.

Jim is frustrated with the alternator drive belt on his 182. It comes off the pulleys about once every 10 hours. Paul said it’s very common. Counterbalances on the crankshaft are a potential problem, but a last resort. Grooves in the pulley could also be the culprit, as could excessive play on the shaft on the drive pulley. Paul also suggests trying a solid belt instead of Jim's current segmented version.

David is trying to make a kit of tools and spare parts to take while on cross-countries, and he is looking for recommendations. Paul said he has two criteria. First is something you’re willing to change. The second is to take any special tools or parts that most shops don’t carry. Mike said he takes common-failure items for the specific airplane. On his 310 he carries a vacuum pump, for example. Colleen said she always carries duct tape and tie raps, a screwdriver in order to take the cowl off, and a first-aid kit.

Dustin has a controversial question about a recent interaction with a shop. During the buying process of an engine overhaul, an owner found out a supplier offered the shop $2,000 to the shop if the owner went with them. The owner found out thanks to the shop's honest disclosures, but questioned if this is an ethical practice. Mike thinks this is no different than a wholesale/retail markup. Paul said he understands why this feels different, but he thinks it’s legit. Mike recommends asking your shop what they are making on your part, and if you’re not happy with the amount to negotiate it.