Oct 1, 2025 · 49 min
AT
Leisure
Ask the A&Ps
AOPA
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.
- 110 episodes
- Updated Yesterday
Episodes110
- ATSep 17, 2025 · 53 min
"You have a lot of splaining to do"
How to cycle the prop, cam spalding, and inop parts
- ATSep 1, 2025 · 56 min
"Mechanics can be ornery sometimes"
How do you fix a fix? Mike, Paul, and Colleen explore STC challenges, including parts, wrong installations, and ADS-B that isn't working. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org Full notes below: Barat has a Cirrus SR22 with an STC air conditioner. The driveshaft recently broke and he’s wondering how to fix it. Some mechanics he’s spoken to won’t use alternative parts, but others will. Mike said it’s not unlike altering the original type certificate. The question is whether your alternative to the supplemental type certificate is major or minor. Mike and Paul agree that it sounds like a minor alteration because the parts are now available from Cirrus, based on the STC that Barat had it installed previously. Kevin has an LX7 with advanced avionics. A month or so after a trip through the Southwest, he got a letter from the FAA saying his ADS-B wasn’t functioning properly. He’s wondering how to know whether or not it’s working. Mike said he thinks this problem is similar to the transponder question. Even though there’s a reg that requires that an installed transponder be on and functioning, there’s no way to know if that’s the case, other than an ATC report or during a 24-month check. The hosts suggest you could do the same with ADS-B, requesting a report from the FAA on a periodic basis. Byron has a Cessna 170 that he purchased three years ago. The airplane came with vortex generators that were installed incorrectly. Byron is wondering what he should do next in terms of holding the original installer accountable. The hosts caution him on going to the FAA because they can’t investigate halfway. Mike wonders whether the FAA would actually go after the mechanic, since it’s not a safety of flight issue. Paul thinks making an honest mistake is usually let off from the FAA with minor infractions.
- ATAug 22, 2025 · 45 min
Live from Airventure 2025
The audience questions come fast at the AOPA tent
- ATAug 1, 2025 · 1 hr 2 min
"That'd be like putting grease on the road"
Grease options, lean of peak temps, break-in, composite cracks
- ATJul 15, 2025 · 41 min
"That's one way to flat spot a tire"
Parking brakes, valve guides, and preflight gotchas
- ATJul 1, 2025 · 1 hr 1 min
"An airplane with no engine is worth nothing"
Oil issues cause problems for owners
- ATJun 15, 2025 · 1 hr 3 min
"You have to cart mogas around like a homeless person"
Fuel flow, mogas, and overhaul concerns
- ATJun 1, 2025 · 1 hr
"You have license to go zorching around"
An owner wants to fly his engine after it sat for 7 years. Plus, prop strike at the shop, lean of peak, and break-in trouble. Email podcasts@aopa.org for a chance to be on the show. Join the world's largest aviation community at aopa.org/join Full episode notes below: Rupert is having trouble breaking in his new cylinders. They have five hours and the temperatures are still trying to go above 420 degrees on departure. They’ve checked fuel flow and baffling. In a twist of irony he is causing his cylinders to run too hot because the break-in is being prolonged because he won’t run the engine hard enough. Paul said Comanche’s have notoriously have poor baffling, which can also compound the problem. They recommend running it hard for a few hours and not to worry about the temps being around 420. Craig has a Pitts that was damaged on a high-power run-up after his annual. The tail came up and hit the prop. He’s wondering if there’s something else they should inspect since the case is going to be open. His crank is subject to an AD. The associated service bulletin requires replacement if the case is opened, but the AD does not. He said the insurance has agreed to replace the crankshaft anyway. They said other than close cylinder inspections, it sounds like he’s fully covered. Larry was finding that the lean of peak indication on his Dynon would show that he was lean of peak before the cylinders were actually there. He found a short paragraph in the manual that says if he changes the horsepower percent rating, it works fine. He also describes a procedure in the Dynon that basically recreates the GAMI lean test. Mike describes how Savvy does the AI engine modeling. The amount of air or fuel going into the engine will be the limiting power factor. In rich of peak, fuel is abundant, so air is the limiting factor. In lean of peak, fuel is the limiting factor. Dave last ran his engine 7 years ago. He mixed oil and camgard, put it into a pressurized tank, and sprayed it under pressure into every place he could. He’s changed desiccant plugs, and had a dehumidifier running as well. If he has pitting he’s wondering if it’s dangerous to fly. Paul said airplanes don’t fall out of the sky because of pitting on the camshaft, and Mike added that they do fall out of the sky after taking off cylinders to look for signs of corrosion. Either the engine will make metal in the filter or it won’t, he said. If the filter is clean for the next 100 hours he dodged a bullet. Nothing that could be wrong corrosion wise is a safety of flight item. It’s a safety of wallet item. Paul said he would recommend changing the oil soon after running it. If the cylinders don’t look corroded the bottom end probably isn’t either, Mike said. Paul suggests he crank the engine with one set of plugs inoperative until he gets an oil pressure indication, and then start it normally.
- ATMay 15, 2025 · 1 hr 11 min
"Continentals burn valves and Lycomings stick valves"
Valves are sticking all over as the hosts give advice on how to avoid pulling cylinders. Send your questions to podcasts@aopa.org for a chance to be on the show. Join the world's largest aviation community at aopa.org/join Full notes below: Rick has a 182 with a new Pponk engine and he’s burning lots of exhaust valves. He’s wondering what he should change operationally. Paul said to borescope more frequently to find the asymmetric burn patterns before they need to be replaced, and if they start to have asymmetric patterns to lap them immediately. He recommends borescoping every 100 hours. Mike gives some initial results of Savvy Aviation’s borescope initiative, which after 100,000 images found that 7 or 8 percent of valves showed signs of heat distress. Twenty five percent of the engines had at least one valve that was heat distressed. About 85 percent of those valves were in the early stage of distress and could be lapped. Only about 15 percent were considered late stage. Brad has an SR22 with an IO-550 that had high oil usage. They pulled a cylinder, rehoned it and put on new rings. Later he started asking questions about torquing the through bolts, and the shop told him they held a wrench on the other side, but didn’t torque both sides. He’s wondering if he should go back and retorque the bolts. Mike and Paul think he’s probably ok. Bruce is sick of sniffing gas fumes. They installed new fuel senders and a digital fuel gauge in their 172. They followed the procedure to calibrate the fuel senders, but he’s having trouble getting it correct. He’s as much as two gallons off from what it should be. Paul starts by asking what bucket Bruce is using because the utility buckets from the home stores are unreliable as calibrated containers, he said. The other issue is the wet wing construction, which can lead to dams that make it difficult to fully defuel or refuel. Bruce has even accounted for temperature. He’s within half a gallon on one side, which Paul said is usually as close as you can get it. Ed is stirring the pot. He read that in an article in the American Bonanza Society publication that operating lean of peak is bad for engines. Obviously the hosts disagree, and a discussion of the merits of rich of peak and lean of peak ensues.
- ATMay 1, 2025 · 1 hr 6 min
"My airplane is a flying experiment"
Engines go bang, stick, and hold on to oil this episode
- ATApr 15, 2025 · 1 hr 2 min
"They put all their maintenance records on napkins"
Picking the right aircraft logbook, Continental bulletins, lead scavenging, and ADs
- ATApr 1, 2025 · 54 min
"Keep torturing those airplanes...and students"
Shutting down engines, electrical problems, and more
- ATMar 15, 2025 · 57 min
"Shame on you for even thinking about it"
Lead deposits, turbo tips, setting engine monitors, and trading good airplanes
- ATMar 1, 2025 · 1 hr 5 min
"If that doesn't work you've got the flame thrower option"
Engine vibrations, getting the bugs out, leaning for takeoff, and flap problems
- ATFeb 15, 2025 · 1 hr 8 min
"Your airplane is on a full-time IV drip"
Oil pressure and temperature issues, compression test benefits
- ATFeb 1, 2025 · 1 hr 9 min
"You don’t know if he’s going to hit you with a wrench or a lawsuit"
Should you overhaul an engine based on oil analysis? The hosts answer this question, plus fuel pumps, valve grinding, and a pesky hot cylinder. Email podcasts@aopa.org for a chance to be on the show. Join the world's largest aviation community at aopa.org/join Full notes below: David is worried about the relatively new IO-470 in his Bonanza. His oil analysis history shows a lot of aluminum, and recently, high on all metals. The narrative said to check for crankcase fretting. Paul said he would check the torque on the through bolts for piece of mind. Mike said he’s not particularly concerned about any of the numbers on the report. He said oil analysis is only a trend monitoring system. Once you establish a baseline you look for major diversions from the report. Colleen disagrees and said they aren’t stable, but have been increasing. There’s nothing that would cause all numbers to go up unless there’s dirt or a bad sample. Paul then details how David can use his borescope to look at the cam, a few lobes, lifters, and so on. It might not give him any information, but it could give him some reassurance that things are ok. Colleen suggests inspecting the pick-up screen if he can. Mike said he would never tear down an engine based on an oil report. Maurice wants to know about the fuel pump on his Mooney M20J with a Continental IO-550. He has an altitude compensating fuel pump, and he wants to know how to use it. Mike explains that it automatically leans for you in the climb. Once he’s ready to lean in cruise, it’s time to lean manually. Jared is ready to start grinding some valves. As he gets deeper into lapping valves in place, he’s wondering what sort of threats there are. Is it maintenance to the extent of being subjected to potential maintenance induced failures? Is it better to wait until a valve needs it, or could it be done pre-emptively? Mike said he wouldn’t necessarily do it pre-emptively, but if he sees any sort of potential deposits then it can be worth doing it. Paul said they go through an inspection process afterwards, including making sure the grinding compound is cleaned up as well as possible, that the valve keeper is properly in place, and that the bolts holding the rocker shaft holds are torqued properly. Paul said it’s critical to get another set of eyes and not check yourself. The hosts haven’t heard of any failures from lapping. Chris has an O-540 in his Cherokee 6 that was recently overhauled. His number 6 cylinder spikes up to 450 degrees CHT on takeoff and he can’t figure out why. Mike looked at his data going back before the current engine and found that even the old engine had high temps on number 6. Chris finds that the cylinder also run the leanest. Paul suggests it could be an induction leak.
- ATJan 15, 2025 · 1 hr 4 min
"There's a serious brain drain in aviation maintenance"
Power loss, how to train technicians, and engine theory
- ATJan 1, 2025 · 1 hr 16 min
"Check it, log it, and then relax"
A prop strike without a prop, broken rings, carbon monoxide, and Continental rpm advice
- ATDec 15, 2024 · 59 min
"There’s a reason they call these amateur built"
How to check the oil, leaning basics, erratic idles, and oil analysis concerns