Ask the A&Ps Podcast By AOPA cover art

Ask the A&Ps

Ask the A&Ps

By: AOPA
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Experts Mike Busch, Paul New, and Colleen Sterling answer your toughest aviation maintenance questions. Submit questions to podcasts@aopa.org. New episodes are released the first and fifteenth of every month.
Episodes
  • "That installation is fraught with peril"

    "That installation is fraught with peril"
    Apr 1 2026
    How much should a mechanic tell a client during an annual? Mike, Paul, and Colleen handle this question and more. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join Full notes below: Justin flies a Twin Bonanza and cylinder 5 on his left engine takes as much as a minute to fire up and start running. It comes online fastest if he goes very lean quickly after starting. He's pulled the valve cover and springs off, and it's not a sticky valve, and he's reamed the valve guides. Mike wonders if it could be a primer problem. Justin disconnected the primer line, ran the boost pump, and checked for leakage and couldn't find any. Paul suggests taking the line off, capping off the injector, and then trying it. Jorg is trying to make sense of his data. He has a K35 in Austria and he has GAMI injectors and an engine monitor on his IO-470. He has a low CHT on the number 6 cylinder, and it's the first one to go on the lean side, and it shuts down first if they go very lean. An induction leak test seemed fine, and his GAMI spread is less than a gallon an hour. The valve was also lapped. Mike said a low probability culprit could be if the bleed air holes in the injector nozzle were plugged, since they don't seem to have an impact at wide open throttle, but would at a reduced throttle. Mark saw a Youtube video and is now wondering if there's danger lurking in the alternator. The video mentioned how an alternator elastomer coupler failure could lead to a catastrophic engine failure. Paul said the installation is critical because of some critical components. Mike thinks the video relies on old information. He said Continental used to employ a spring, which would come apart and throw large chunks of metal into the engine. The coupler is meant in part to protect the engine if the alternator seized, but sometimes the coupler would fail and cause its own failure. The newer versions have an elastic or rubber piece instead of a steel spring, which shouldn't cause an engine failure. Chaz is an A&P/IA and he wants the team to weigh in on the debate as to whether the inspector should give pilots a full list of squawks or only the airworthiness issues. He personally thinks he should give the whole list so the owner knows where he stands. The hosts agree that the full list is preferable. The mechanic is giving a full slate of options, and not a required list. Airworthiness items can be listed separately or be flagged.
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    54 mins
  • "I'm an old mechanic and really like the idea of priming and painting"

    "I'm an old mechanic and really like the idea of priming and painting"
    Mar 15 2026
    Quick corrosion, long-lasting engines, and mobility mods are on tap for this episode. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join Full episode notes below: Patrick is looking for the right fit on a potential aircraft purchase. He had a shoulder replacement and lost some mobility in his right shoulder. He’s wondering if he could get an accommodation on things like flap controls. Paul suggests he look for an older Cessna with the progressive flap switch, not the one with pre-selected detents. The hosts thing that up/down progressive switch would be a minor alteration and just a few wires. The pre-select flap lever is probably a major alteration and a lot of work because there’s a lot going on behind the panel. Jeff has a Maule M7 on floats and is battling corrosion. Recently he did a salt water landing, sat for about 3 hours in the water, flew home, and his left main gear didn’t rotate as he landed. He saw that the main forks had a bloom of corrosion that froze the wheel. He washed everything in fresh water, and then next day saw a bloom on the other gear as well. He is wondering if he had a stray current given how quickly it developed. Mike thinks it’s unlikely because if the battery if off it’s completely isolated from the rest of the system, meaning their shouldn’t be a way for the battery to provide electrical current anywhere on the airframe. Lindsay recently purchased a Piper Lance and wants to make sure she keeps the engine going as long as she can. They go over the basics and make sure she is boroscoping the cylinders, fly it regularly, etc. Mark is wondering how soon is too soon to put in cowl plugs after flying. He has a Cessna 206 and he’s wondering if he can put in the cowl plugs right away. The concern is about the plugs, not the engine, Paul said. The hosts all agree that he's fine to seal the cowl off as soon as he likes.
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    49 mins
  • "That's an oft-reported myth"

    "That's an oft-reported myth"
    Mar 1 2026
    Is going past TBO more expensive? Plus fuel vents and turbocharger temps. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join Full episode notes below: Mike wonders if running past TBO actually costs more. He has a Mooney and has heard that overhauls far beyond TBO can cost more as a result of having to replace more parts. That is an oft-reported myth, Mike says. The only things that can cause an up charge on most field overhauls are having to replace the case or the crankshaft. Otherwise it’s a fixed price. Paul says the top engine generally goes into the trash. On the crankshaft, they usually just have to polish it or grind it. There’s no repairing a crankshaft. If it’s bad, it was bad because it had some other type of problem. You can go thousands of hours on crankshafts. Mike said Lycoming had a white paper on their website that said crankshafts are generally good for 14,000 hours. Cracks on the case can be welded. Mark has an early 182 and he’s having issues with the fuel caps properly venting. He has noticed that once you fill the tanks with cold fuel, there doesn’t appear to be an outflow vent. Paul said there’s a small weep hole that allows the expanded fuel to vent. But Mark’s tanks still aren’t venting. He pulled it out but didn’t seem to find a weep hole. He said it looks original and has an early Cessna part number. If the fuel is pouring out it needs to be replaced because the check valve is bad. The wing will balloon and can cause structural damage without a weep hole. He said when he removes the cap a big woosh of air will come out, indicating the fuel isn’t venting out as it expands. Jim is wondering how TIT and EGT intersect. He flies a turbo Saratoga and has been experimenting lean of peak and rich of peak. He’s noticed a significant difference between EGT and TIT. If the TIT is farther away from the engine, he’s wondering why it’s hotter than EGT. He’s also wondering how hot he can let the turbocharger get. Mike said TIT is hotter because the EGT probe is only seeing gas flow for less than a third of the time, and only when the exhaust valve is open. The EGT probe actually measures a “probe” temperature that averages the temps over time. When the gas gets to the TIT probe it’s a constant heat from all cylinders all the time. Redline on his TIT is 1,650 degrees, which Mike said is a continuous operation limit. Paul asked what the exhaust system is made of because that matters. He suggests not exceeding the red line. In cruise, the lower you can keep the TITs, the longer the system will last. Mike limits his TIT to 1,600.
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    50 mins
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I enjoy the varied questions and the discussions regarding the issues. I have learned a lot.

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Excellent information since I am just a brand new power plant and soon to be airframe mechanic there’s so much to learn what is not being taught at schools and some very good information has been gained from your show thank you.

I look forward to your next podcast.

Highly appreciate your show!

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Wonderful podcast. Learned so much in just the first few episodes! Highly recommend it to anyone!

Wonderful podcast. Learned so much in just the first few episodes!

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I binged through the whole series. I am a gearhead and the family fixit guy. I love car shows, and this aviation themed podcast definitely has appealed to me. Even if you don't normally indulge in aviation activities, I suggest giving this podcast a listen. I think it will have cross appeal for many with other interests. please

Binged and listened to the whole series

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