AOPA

Ask the A&Ps

A Leisure , Education and How To podcast

About the show

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.

Newest episodes

Shock cooling is a myth

Nov 2, 2026 51 min

Engines fail when they're new, not old. Plus, leaning with carb heat, questions to ask as a renter, and Cirrus cylinder cracking. 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: Kevin is looking to rent an airplane from a private owner and he's looking for opportunities on Facebook. When he goes to see the airplane and meet the owner, Kevin is wondering what he should ask. Paul suggests staring with the logbooks and looking for the annual inspection sign off with a note that the ADs have been complied with. Colleen says to start with the books and then go through a thorough pre-flight. If the owner balks at repairs that you consider essential, she suggests walking. The hosts debate the importance of how many people fly the airplane, but settle on the fact that what really matters is a standard squawk sheet. Alan is concerned about the new Cirrus service bulletin that describes cylinder cracks on Continental engines. He asked the shop to inspect per the service bulletin and the shop found a crack where the SB describes. Paul said all you can do at this point is to inspect it frequently, ideally every time the cowling is off. The manifold pressure pull and other pilot actions won't impact this. It's a design defect that has nothing to do with pliot actions.Ike flies an O-200 and he thinks it runs better lean with full carb heat on while in cruise. He's wondering if the unfiltered air is bad for the engine. The hosts say so long as he's only doing it in cruise, it's no problem. Colleen does this with one of her airplanes and her oil analysis doesn't show any additional silica in her oil. Mike suggests he try partial carb heat to get the same effect.Lawrence and his son fly the family's new airplane. He wants to instruct, and his son wants to fly for a career. They've flown 400 hours or so, and the engine is around 2,000 hours since TBO. They do a lot of their own maintenance un...

You need to tackle your mechanic

Oct 15, 2026 1 hr 1 min

What happens when you shut off the mags in flight? Mike, Paul, and Colleen answer this question, plus Cirrus cylinder woes, lapping technique, and more. 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: Jeff is questioning the part of his checklist that calls for turning off the mags just before shutting down. He remembers doing this accidentially in flight training and his instructor becoming somewhat panicked. The hosts explain that turning off the mags before shutting down is safe and determines if the P-lead is intact. Accidentally turning them off in flight is a different story. Unburned fuel in the exhaust will ignite rapidly and probably ruin the exhaust if you were to immediately turn them back on. If this happens, Paul recommends leaning the mixture completely, counting a few seconds, turning the mags back to both and then slowly brining up the mixture again. By doing this you'll hopefully allow the collected fuel to dissipate. Brian asks about Cirrus cylinder problems after a recently failure caused his partner to execute an emergency landing. The hosts explain that Continental has been having issues with cylinders on certain big bore Continentals. There's an AD that requires the cylinder exhaust ports to be filed, and while they've seen many cracks where the AD had supposedly complied with, Mike said the issue is that most mechanics aren't filing away enough material. However, Paul has also seen cases where the AD was properly complied with and the cylinder still cracked, and even new cylinders that aren't covered by the AD are cracking. He recommends doing a careful visual inspection for cracking near the exhaust port anytime the cowling is off. Yuriy wonders how much exhaust valve sidestepping is too much. Mike said he's had big sidestepping in many of his valves with no adverse effects. They recommend continuing to borsescope a few times a year to ensure the val...

They will find you

Oct 1, 2026 57 min

The right oil temp, inop and new equipment, and oily turbos are on tap for this episode. 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: Grace’s engine runs rough above about 2,000 rpm. She currently has a single probe monitor, and is waiting to install a more comprehensive engine monitor. She’s worried about running too cold, given that her oil temp is relatively low, even in the Pennsylvania summer. It’s not too low in her 180-horsepower Sundowner, Paul said. She’s unsure what’s too cool and how to check to see if there’s too much moisture in the oil, which would indicate it’s not running hot enough to burn off the moisture. Mike said that an oil analysis is the best way to tell, and so far hers have been consistently good. Boris is looking deep into the regs and is wondering about equipment failures. He has a friend with a Piper Seminole and the manifold pressure gauge was inop. The gauge isn’t listed in the type certificate, minimum equipment list, etc. The current Part 23 doesn’t specifically require a manifold pressure gauge with a controllable pitch propeller. However, 91.113(d) says that the equipment must be operational as originally certified, and Part 23 at the time required a manifold pressure gauge for an engine with a controllable pitch propeller. Mark is wondering how turbos impact oil. Mike had written that the ratio of displacement to oil capacity is an indicator of how long you can go between changes. An IO-550 with a small sump calls for more frequent oil changes, for example. The other thing Mark has heard is that an airplane with a turbo should have more frequent oil changes, and he’s wondering if that’s true. The turbocharger doesn’t make the oil dirty, Mike says. If the oil cooler is working properly it also shouldn’t make the oil run hotter. Paul also said not to worry because it doesn’t seem to make a difference. Mike said he’s seen r...

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All episodes

Shock cooling is a myth

Nov 2, 2026 51 min

You need to tackle your mechanic

Oct 15, 2026 1 hr 1 min

They will find you

Oct 1, 2026 57 min

Be careful what you ask for

Sep 16, 2026 1 hr 3 min

A caller wants to know what they don't teach you in A&P school. Plus AD compliance, a scary engine failure, and putting the lean in lean of peak. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join KC wonders why ADs appear on some logbook entries as having been complied with with a terminating action, and in future entries the AD reappears. He discovered this was a common occurrence when he was looking through logbooks as he and a partner were purchasing an airplane. Mike said you can't tell from an AD compliance summary whether something has been permanently complied with. That is found in the logbook through some sort of permanent change, like a kit or STC. If some other IA signs off the AD compliance again it could be because the IA simply missed that the AD was permanently complied with. Paul said he always assumes an airplane he sees for the first time has errors in AD records compliance and he verifies everything himself. Paul said this often happens because the part was changed somewhere in the airplane's history to make it no longer permanently complied with. Jeff is looking to fine-tune his lean of peak performance. He flies an RV-10 with an IO-540. He has a small window in lean of peak where he is running a bit rough, but if he runs more rich the CHTs will climb into the 360-degree range. Mike said Jeff is trying to run too cool. A Lycoming typically runs 20 degrees hotter than a Continental, so he said flying at 400 degrees CHT is perfect and nothing to worry about. Keeping it cooler won't necessarily matter. Mark is going to A&P school on the side for additional enjoyment and greater involvement in his airplane maintenance. He is at a Part 147 school, and he feels like the education is good, but he's wondering what else he needs to know about GA maintenance. Paul explains that school is a great intro to the various topics, but it's not long enough to be detailed in all facets of av...

Live from AirVenture 2026, Session 2

Sep 1, 2026 37 min

Join Mike, Paul, and Colleen for a second live session from EAA AirVenture in Oshkosh 2026 as they are try to answer the audience's most pressing maintenance questions. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join

Live from AirVenture 2026

Aug 15, 2026 31 min

Join Mike, Paul, and Colleen as they take questions live from the audience at the AOPA tent at EAA AirVenture 2026.

We're in the twenty-first century here folks

Aug 1, 2026 45 min

Which oil is best, where is the oil going, running lean of peak with a carb, and how to fly a turbo 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: Chris' American Champion Super Decathlon has an oil consumption issue. While his engine was apart after a prop strike the cylinders were honed, and he broke it in properly. He has since replaced cylinders, broke it again, and is still only getting three hours per quart. He said oil is coming out of the fuel servo, which everyone has told him is normal, but the hosts quickly disagree. Mike suggests borescoping the back side of the intake valves and looking to see if one is oily. If it is, chances are the intake valve isn't seating properly and is being sucked back up and burned. Chris is trying to run lean of peak with a carbureted engine. He has an O-360 and he wants to make sure he's not doing anything wrong. His technique is to lean to the point of roughness and enrichen only enough to smooth things out. Mike said that's a solid technique and that most four-cylinder carbureted Lycomings run well lean of peak because they have a good balanced mixture distribution. Mike said not to worry about how lean he is. If the temperatures are within limits and the engine is running smoothly, you are good. James has a Piper Turbo Lance and he wants to make sure he is running it properly. His manual has a five-minute limitation on takeoff power, and he's wondering where that comes from. Paul said the older Cessna 210s have a five-minute limit at 2,700 rpm, and they discovered that the limit was all about noise, and not about the health of the engine. They told James to check section 2 of his POH, limitations, which would require the procedure regardless of the reason. Mason uses Aeroshell 100 plus Cam Guard. He's heard that straight weight oil remains on engine parts longer during periods of mis-use....

Your mechanic feels worse than you do

Jul 15, 2026 48 min

A fidgety fuel problem, octane ratings, and water in the oil are on tap for this episode. 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: Gareth has a turbo Arrow and he's been fighting a problem with fluctuation fuel flow. Sometimes the engine quits on the ground or runs rough in the air. They've checked the fuel spider, fixed intake leaks, overhauled the fuel pump, an exhaust leak, and much more. Paul is convinced that air is entering the system or there is a vapor issue. He suggests checking the heat shields near hot parts of the engine, etc. Mike suggests that it could be related to upper deck pressure, which controls the aneroid in the fuel pump. Matt wonders if fuel octane impacts timing. He has a Cessna 150 and is running autogas, and he's wondering if his ignition timing should be changed to accommodate a difference in octane. Paul said the airplane was certified with 80 octane, so it's fine to keep the timing as it is. Scott is wondering about an alternative to safety wire. A company called Bergen makes a safety wire alternative and he's wondering if it's legal to use on FAA certified airplanes. Mike said even if the company doesn't say it's FAA certified that it would almost certainly be a minor alteration, and therefore at the discretion of the installing mechanic. Paul uses them in certain applications and likes them. Scott has a IO-540 on a Socata Trinidad and was about to overhaul his engine, but found Mike's maintenance philosophy. He's now at 2,300 hours and counting. Everything looks good except that water occasionally shows up in his oil analysis, and he's struck out finding help through his mechanic. The water is a byproduct of the combustion process. When you shut down the crankcase is full of steam, and that steam then condenses into water. You can help keep that water down by taking off the oil cap after shutting down, or by hooking up an engine dehum...

It's in your head

Jul 1, 2026 52 min

Very cold cylinders, sort of warm cylinders, turbochargers, and pressurized mags 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: Bill has a Cessna 182S with the Lycoming IO-540 and he has a temperature issue with his number 2 cylinder. Climbing out at full rich he would back up the mixture a bit at 1,000 or 2,000 feet and the CHT would climb to about 405. By going full rich again he can keep it below 400 degrees. Mike said the problem is totally in Bill's head. A CHT of 405 is a perfectly respectable temperature for a Lycoming. The redline on the cylinder is 500 degrees, so there's no need to worry about 405. Mike recommends keeping Lycoming cylinders below about 420 degrees. Daniel has a Columbia 400 with a TSIO-550. He's been thinking about how car turbochargers don't have enough exhaust gas pressure to start working until a few thousand RPM and he's wondering if airplane turbos are the same. Paul said the waste gate closes immediately upon startup, so all the exhaust runs through the turbocharger from the beginning. Bob is wondering about corrosion on pressurized magnetos. Mike has previously explained that they are prone to corrosion because of water entering the system. Bob wonders if because the water entering the system can only be in the form of water vapor and because the vapor is coming from clouds, which are low in the contaminate that cause corrosion, if Mike might be overstating the problem. Mike doesn't disagree with Bob's theory, but in practice the issue is real and prevalent. Adam flies lean of peak in his Columbia and his CHTs can be as low as around 240 degrees and he's wondering if he's flying too cool and what he should do about it. Paul asks how far lean of peak he's flying. Adam thinks it's about 40 degrees, but at a fuel flow of 12.5 gallons per hour at an RPM of 2400. The hosts agree he's flying very lean. The...

I always try to buy high and sell low

Jun 15, 2026 49 min

Carbon monoxide, kickbacks, avionics upgrades, and leaning radials are on tap. 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: Bill has a Cessna 210 and in climb he gets 50-100 ppm on his CO gauge. When he levels and goes lean of peak it goes back to normal. He's also noticed that if he puts the heat on he also doesn't have a high reading on his gauge. It's not from a hole in the firewall, Paul says. The most common places it can come in are from the header tanks where they come in through the belly, the steering boots on the nose gear, the down-lock boots on the main gear down-locks, the pilot's cabin door (look for light in the lower left corner of the door for light while in flight). The level goes down when he turns on the heat because he's pressurizing the cabin, which keeps the CO draft out. And he doesn't get it at LOP because he doesn't have nearly as much un-combusted fuel in this state, the driver of CO. Bob has a Cessna 182 and it has a North Point (nee P-Ponk) engine with an MT prop and experienced a kickback during start. He's wondering how to move forward. His mechanic recommended removing one of the impulse couplings (he has two). The kickback would occur if one of them didn't activate properly, Paul said. If the ignition fires early during the start process, the impulse coupling delays the spark until top dead center. If it fails, it doesn't delay it, and the kickback occurs. When the kickback happens, the nylon gears in the mags are stressed, the spring in the starter adapter can break. The hosts recommend changing that and inspecting the impulse coupling. The hosts gristle when Bob mentioned the MT prop. It's so much lighter than aluminum, and they result in many more kickbacks. Kyle is wondering about the leaning philosophy on the R-985 engine on the Beaver he flies. The manual cautions against leaning below 5,000 feet, and he's wondering what the hosts t...

Too much data is a bad thing

Jun 1, 2026 50 min

Worn intake valves, pitted camshafts, shock cooling, and AD compliance are on the docket. 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: Norm wonders whether condition-based maintenance and inspections failed him. He is co-owners in an airplane with a Lycoming IO-360, and after a few years they found a crack in the crankcase. The engine was torn down and found to have some rust on the cylinder walls, scoring on the crankshaft, and a worn and pitted lifter. They had been borescoping, doing oil analysis, looking at the filter, and never found any concerns. The hosts say the approach worked perfectly. The point of condition-based maintenance is to fix safety related problems, and they argue that all Norm's issues were financial issues. Mike argues that the lifter wear could have been found with by measuring the valve opening, but that it wouldn't have necessarily resulted in a teardown. The oil analysis wouldn't have found anything because the metal chunks were too large, and although a magnet over the filter material may have helped, he's not sure that would have resulted in a teardown either. The lesson is that the airplane was safe, despite the condition concerns. Jay has an RV with an experimental IO-540 that he loves. A look at the cylinder data found that one of his intake valves was eroding. As the shop dug into the engine they found a few other issues, including pitting on the camshaft. An IRAN is going to cost him maybe $20,000 or $30,000 less than an overhaul, so he's wondering if it's ok to save the money or should he just overhaul the engine while it's off. The hosts tell him to save his money. The only reason they would overhaul now is to increase the market value if he were planning on selling. Otherwise there's little benefit. Ronan wonders how to interpret the data on his friend's Piper Arrow as regards shock cooling. They often get the alerts on the Garmin e...

TBO is not a reason to do anything to an engine

May 15, 2026 57 min

Rising temperatures, unnecessary overhauls, unusual rigging, and ancient cloth in the wheel well are featured. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join

If you lose a cylinder in your Cessna 150 you are down on a road somewhere

May 1, 2026 50 min

Sticky valves, sleepy valves, and valves destined for the trash are on tap 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: Mac is trying to get a cylinder to wake up on his Piper Lance. The engine ran rough, and a magneto clearing procedure didn't help. The number 5 cylinder was dropping off according to the engine monitor. It's also next to the turbocharging exhaust. His A&P thought maybe the injector line being next to the pipe might be causing a problem. It only happens after landing, not while flying. Paul thinks it would be a more widespread issue if the plumbing engineering were the issue. The aux fuel pump stops it from happening. Mike suggests a mixture that's too lean could cause this. They suggest checking the idle mixture rise on shutdown. The rpm should rise 25-50 when pulling the mixture at idle. If it doesn't rise as much it's too lean, and if it rises too much it's too rich. They also suggest running a GAMI lean test to determine if the cylinder is a lean outlier. Conor has a Cessna 150. On the way back from Oshkosh last year he experienced a stuck valve. There was discoloration from being hot when the cylinder was pulled. He leans aggressively. He's wondering if he's leaning too aggressively and is getting the engine too hot. He leans to roughness and enrichens only until it gets smooth. The hosts think the engine has to be in detonation for it to get too hot. The piston tops are fine under borescope, so the hosts think it's fine. Andrew wants to knock the rust off his A&P certificate. The hosts suggest the new Savvy Aviation IA recurrent course. It's a free 8-hour course to help refresh his memory. Beyond that, Paul suggests a 172 course, which is the airplane he plans on buying. There really isn't a hands-on refresher course, according to Colleen. She suggests he could hire an A&P and work alongside him or her to brush up. He could...

Am I doing anything evil?

Apr 15, 2026 57 min

Avoiding maintenance can be a good thing when what's recommended is unnecessary. 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: Dominick is questioning his mechanic's advice on prop overhauls. He has a Cessna 310 and his left rpm is too low on approach when the control is full forward. It's not an issue on the ground or on takeoff. His mechanic recommends overhauling the propeller, and since he's doing one he should do both. He swapped governors and that didn't change anything. He sent the prop back for IRAN and they didn't find anything significant. Paul suggests it's the low pitch stops. This is a classic twin owner trap, Mike says. The two engines are never the same. Everyone agrees that he can leave it as is. Vas has an RV-10 and the Lycoming IO-540 has been acting up. During some flight training in the airplane, he noticed oil consumption went up, metal was in the filter, and he ended up overhauling the engine. He's wondering if he should have just pulled a cylinder instead. He was flying 140 hours a year, and he's wondering why he would get corrosion. Higher oil consumption isn't a corrosion problem, but the cam and lifter spalding do indicate it. These were unrelated problems, according to Mike. Paul thinks it's possible the damage was already in place when there was a previous IRAN. They settle on it being a lifter hardening issue, meaning poorly manufactured parts. Jim has a Mooney M20K and an instructor showed him a leaning procedure while in cruise at 9,000 feet. They set the manifold pressure to 30 inches, the RPM at 2300, and then pulled the fuel back to 11 gph. That's how he's been leaning ever since. CHTs are in the 360/370-degree range. He trails the cowl flaps to try and cool the CHTs if it's a hot summer day. If the TIT gets too high he'll enrichen it just a touch. Paul said if he adds more fuel and the TIT goes down, he's running rich of peak. Peter...

That installation is fraught with peril

Apr 1, 2026 53 min

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 i...

"I'm an old mechanic and really like the idea of priming and painting"

Mar 15, 2026 49 min

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.

That's an oft-reported myth

Mar 1, 2026 49 min

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...

Is this like pulling a mattress tag off?

Feb 15, 2026 54 min

What exactly should we be looking for in our cylinders? Plus torque tales, making TBO, and overzealous manufacturers. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join 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...

The owner can't do maintenance because the owner doesn't have arms

Feb 4, 2026 50 min

The definitive guide to owner maintenance, slipping starter adapters, and close CHT tolerances. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join

You're going to give him nightmares

Jan 15, 2026 56 min

Creative leaning techniques, rusty cylinders, and odd manifold pressure indications are on tap this time. Send your questions to podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join

He has a piston with a smiley face on it that's not very happy

Jan 1, 2026 42 min

Old engines, rusty airplanes, and a strange valve incident are the puzzlers for Mike, Paul, and Colleen this episode. Send your questions to 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: John has a Beech Musketeer who had an unusual situation with his valve. The valve seat separated from the cylinder barrel and dropped down, striking the piston crown. He's wondering if he did anything to cause this, despite never exceeding 425 degrees CHT. The hosts agree that it was probably a manufacturing error, even though the cylinder had a few hundred hours on it. Mike said the only way this can happen is with a manufacturing problem or a high heat event. Larry has an early SR22 with 3,300 hours on the engine. It's not in need of an overhaul now, but Larry has read those early SR22 cases are more robust, and he's wondering when the time comes if he should overhaul or do a factory reman. The hosts aren't aware of any particular issues that make cases from that generation better, but they do offer some sound advice on the reman versus overhaul question. Mike said that if the engine has been treating him well that Larry should overhaul it. And if it's been a lemon, send it off and get a new one from the factory. Larry is a little worried about resale, since people are skiddish with high-time engines. Mike suggests that an airplane with run-out engines is the best investment because it's been fully depreciated. Any additional time is essentially free. Terry has been looking for a 182 and he saw one in California with corrosion. He wonders how much corrosion is too much. Paul said that according to Terry's photos, he wouldn't think twice about buying the airplane. The general rule is that you can take off only 10 percent of a structure and not worry about it. The skin on top of the wing where the corrosion can be seen is only 25 thousandth of an inch, which means you could only take of...

Just be sure you lube it with something

Dec 15, 2025 44 min

Pre-emptive engine overhauls, upgrading an old electrical system, spark plug anti-seize, and old wood wing concerns are on tap for this episode. Send your questions to 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: Lance inherited some furniture that had lived in the Midwest for 200 years, and began splitting after only a few years after he moved to Salt Lake City. He's wondering if the same concern would hold with wood wings, like those on the Bellanca Viking. The hosts say not to worry. The wood spars are lathered with a varnish that helps keep out moisture, Sitka spruce is resistant to splitting, and Mike said in his experience with Vikings in the 1970s, shops didn't report issues with airplanes that had lived in different parts of the country. Jim has an Arrow and he wants to guard against the long down times we're seeing at overhaul shops. To do so he wonders if she would pick the right time and pre-emptively overhaul his engine, or at least change out the cylinders. Mike, Paul, and Colleen fully lecture poor Jim on the perils of so-called top overhauls, and instead advise him to do nothing more than stock a cylinder in case the time comes and he needs it. Darren is thinking of putting an all-new panel into his Tri-Pacer, and he's wondering if he should upgrade his generator to an alternator when he does it. Paul said he's not worried about the generator when it comes to his avionics, but given that Darren flies at night, Paul thinks an alternator is probably a good idea. Steve is wondering about spark plug anti-seize compounds. He uses the Tempest and Champion products, but found Lycoming's service instructions that prohibits their use. It calls for a copper-based compound, or motor oil. The hosts think the guidance might be a result of getting the carbon-based anti-seize on the insulator, which would cause arcing. They all agree that motor oil would be a bad c...

If you go to 76 percent, the wings will fall off

Dec 1, 2025 51 min

A creative modification, lean of peak with turbocharging, electronic ignition, and oil leaks are on tap. 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: Tom has a turbocharged Mooney and he's wondering how to manage it while lean of peak. The hosts say the first goal is to get on the lean side quickly, and then fine tune once there. They argue you can hear and feel when you're lean of peak, which is how you can expedite it. Then check the CHTs and the T**s to make sure they are below limits. That's it. Paul said in that way turbos have an advantage because it doesn't at what altitude you lean, the numbers should be similar. He tends to lean based solely on fuel flow. Ray is considering going to dual electronic magnetos, but he's concerned about redundancy and the safety of the associated battery. The hosts talk at length about the benefits of dual e-mags, and think that redundancy is better with e-mags than traditional magnetos, so even though you're going away from two independent systems, it's still an improvement. Mike said the TSO for the battery containment is extremely high, and not to worry about thermal runaway. The company must also think so because apparently the experimental version is largely the same, minus the same battery containment. Eric is a new A&P and he's trying to become better informed on the difference between major and minor overhaul. He helped a friend create an external charging port for a battery minder on the belly through an inspection port. The hosts are wowed by the work, and want to do it themselves, and all agree it's a minor alteration. It doesn't stick out into the airflow any more than a GPS antenna, which is a minor alteration. Mike recommends reading FAR Part 1.1, which gives the definition of a major alteration. If it doesn't meet that definition, it's minor. But of course Eric is a scientist by day and doesn't love the ambiguity of...

It's one of the few accidents where you get to choose where it happens

Nov 15, 2025 52 min

Mike, Paul, and Colleen dig deep for some detailed troubleshooting on digital fuel indicators, oil temperature, gear problems, and more this episode. Send your questions to podcast@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join Full notes below: Will's fuel indicators are giving off infrequent red Xs on his Garmin G1000, and it started happening right after maintenance. Paul is suspect that a mechanic caused it, especially because you have to take the wings off to get at the sensors. But he's pleased at Will's level of troubleshooting, which includes info about what happens when the tanks is full, half full, and while turning on the ground. Based on the information, Paul is sure it's a sensor issue. On computer-based fuel indications, a mismatch between multiple sensors can often result in the EFD showing red Xs, he says. It turns out Will's mechanic was able to fix the problem by checking the connectors in the same inspection panel he had opened for the annual. Brad has a Cessna 182 that he keeps in a dry climate but is now flying to the Texas Gulf Coast a few times a month, where it sits for three days. He's wondering how to hold back corrosion. Paul suggests he wash the airplane when he gets home each time, and make sure the inside is fogged with Corrosion-X. Mike said not to worry too much about the engine because his single-weight oil and CamGuard will help protect it for those three days. Carl has a Cessna 210 and twice the landing gear motor didn't stop running when he cycled the gear. Paul then spends a few minutes describing the 210 gear system in great detail, including all the safety of wallet issues. The oil temp is high (235 degrees) on one of the engines on Ben's Twin Comanche. The hosts go through a slew of troubleshooting steps, most of which Ben has already performed. The hosts settle on this being an airflow issue, and not a fuel issue. Mike said the oil temp limit is an oil longevity...

Being an aircraft owner is the hardest job in aviation

Nov 1, 2025 51 min

From maintaining aircraft records to dealing with bad advice and sub-standard parts, Mike, Paul, and Colleen say being an aircraft owner is one of the hardest jobs in aviation. Email your questions to 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: Randy wants to know if circuit breakers have a life limit. He has a Mooney with about 3,000 hours. He had one that was acting up, and was wondering if he should intentionally exercise or change them on some interval. Paul said he recommends to all his clients that they exercise their breakers every few years, since they do tend to corrode. Just tripping it breaks oxidation off the contacts, he said. If you check the resistance before and after the resistance often goes down. Colleen said she replaces a few breakers during each annual. Gary owns a Lake Amphibian with a IO-360 and he runs with fine wire plugs. At the last annual he found four of his Champion plugs had infinite resistance. They otherwise seemed to function normally. He’s wondering what the implications are? Paul said he has boxes old boxes of new Champion plugs that he can’t force himself to throw away, but he refuses to give them away either because he doesn’t trust them. The hosts said they’ve seen many problems with Champion fire wire plugs and the insulators. So they’ve stopped using them and suggest others do as well. They all endorse the massive electrode Champions are just fine, however. Chris helps clients establish aircraft logbooks after they buy their first airplane. Paul said: You should keep as much of the maintenance records as possible for value. Old invoices he puts in a bag and sets them aside. He keeps weight and balance history and it’s nice to have a 337 record. Only the current equipment list is necessary. He’ll recommend customers organize their own logbooks and not pay him to do it. Colleen also keeps a separate spreadsheet for time in servi...

That's an urban legend

Oct 15, 2025 49 min

What's in our oil, how to keep cool (and warm), and lean of peak 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: Mark flies a 182 and he read on a forum that the reason we've had so much spalling of lifters is because they took zinc out of the oil. Mike said this rumor has been going around for years, but doesn't make sense considering zinc was never in aviation oil. It's in STP, which is used as a thread lube. He cautioned not to put that in the engine because it's not ashless. The problem with lifters has been poor manufacturing, Paul said. Bob has an RV-10 and he's been trying to run lean of peak with wide open throttle. His technique has been to reduce rpm to get to 55 or 60% power and then lean. But doing so puts him at around 2,000 rpm. He's worried that running it too low might result in problems. Mike gives Bob a better technique. He said the mixture controls power while lean of peak, although running at a lower rpm is generally better since the combustion event takes longer. By running a lower rpm you're giving the engine more time to burn through the available fuel/air mixture. The low rpm prohibition that Bob is worried about in other airplanes is usually the result of propeller resonance issues, they say. Jeremy wants to know when to plug in the pre-heater. Other pilots have told him he needs to plug it in 10 to 12 hours before flying, but he's checked the temperatures with his engine monitor and found they rise about 35 degrees above ambient in two hours. Paul cautions that the oil won't be that warm, only the metal at the CHT probe, but because Jeremy is running multi-weight oil it doesn't matter. Mike said his rule of thumb is generally to preheat when it gets below 32 degrees F, and that when the rocker covers no longer feel cold to the touch that you're done. In Jeremy's case they agree that two hours seems fine. Johan...

More time to fly, less time to turn wrenches

Oct 1, 2025 49 min

In this episode, Mike, Paul, and Colleen discuss unnecessary maintenance, lean of peak, and flaming exhausts! 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: Mitchell has a Cessna 185 and he's wondering if it's smart to change out the rotocoils on his engine at some pre-determined point in order to avoid uneven heat patterns on his exhaust valves. Paul, despite having done this, advises him to borescope, and only change when he sees an uneven heat pattern. Since Mitchell already borescopes often, Paul thinks he'll catch a faulty rotocoil quickly. Mike suggests that Mitchell could hit the coil with a mallet and if it doesn't turn to change it. Regardless of the test or monitoring method Mitchell chooses, they agree it's unnecessary to change the springs pre-emptively. Doug has some questions about lean of peak. Specifically, he's wondering why his EGT spread is so large when his GAMI spread is only .2 gallons an hour. The hosts remind him that EGT only matters as a way to identify peak. Otherwise the relative and absolute numbers are meaningless. The big gap in EGT and CHT numbers often comes down to cooling inefficiencies, according to Mike. If the numbers indicated that the cylinders were making differential power, Doug would feel the engine roughness. So the hosts think he's doing just fine. Adam wants to know if he can use an automotive alternator in his Cessna 172 under the new VARMA policy. The policy allows for part substitutions when no aviation parts are commercially available. Since 172 alternators are available, he must use one of those. The hosts then discuss what makes an aviation alternator different from an automotive version since Cessna and Piper use GM and Ford alternators. Paul and Colleen focus on the brushes, which are different, and ours turn the opposite direction, which would require a different pully. Although they agree an owner could brin...

You have a lot of splaining to do

Sep 17, 2025 53 min

Gotchas and head-scratchers are the theme this episode, as Mike, Paul, and Colleen help an owner with a pitted camshaft, an inop instrument, a faulty vacuum line, and ops procedures. 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 had two airplanes over the past 10 years with crankshaft pitting, despite regularly flying, hangaring, and using an engine dehydrator. He's wondering if there's anything else he can do to keep the rust away. The hosts focus on the timing of the events and consider that maybe Mike was caught up in a period when Continental had manufactured some sub-standard parts. They are confident Mike did the right thing by having his mechanic use the guidance in Continental's Service Information Directive 05-1B, which describes how to inspect and then when to replace the cam if spalding is found. Trevor has a Cessna 152 and he noticed that the vacuum line near the static sump had been bumped and was disconnected. It's a simple assembly that doesn't require tools to replace, only some teflon thread. He's wondering if that would be acceptable to do under the regulations for preventative maintenance. The hosts agree that it fits the definition of preventative maintenance perfectly, but that changing out the line would trigger the requirement for a static system leak-down test, which doesn't meet the definition. So, although a pilot could probably replace the line, he/she would have to hire a mechanic to do the leak-down test anyway. Brian is the manager of a flying club with a Cherokee that has a persistent inop flag on the S-Tec 30 turn coordinator, and he wants to know if you can label only the inop flag as inop. Mike thinks that's sound logic, but Paul and Colleen are a little more skeptical. When Brian says the airplane is used for checkrides, the hosts agree that DPEs are probably not going to allow it, and to placard the entire autopilot inop....

"Mechanics can be ornery sometimes"

Sep 1, 2025 56 min

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.

Live from Airventure 2025

Aug 22, 2025 45 min

Mike, Paul, and Colleen are in the hot seat as they answer live audience questions from Airventure 2025. We'll be back with our regular show next time. Email podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org/join

That'd be like putting grease on the road

Aug 1, 2025 1 hr 2 min

How to tell the difference between greases? Mike, Paul, and Collen break it down, plus high lean of peak temps, breaking in an engine on an experimental, and composite airframe cracks. 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: Mark wants to make sure he’s clear on which grease to use for which application. The manuals call for specific greases, but there are allowances for those with equivalent specs. But Mark wonders how to determine whether another grease is equivalent. Paul said you need to find the spec sheet for the grease the manufacturer recommends, and the spec sheet for the grease you’re thinking of using to make sure they more or less match. He also mentions Hartzell’s guidance that you can move up in grease numbers, but not down. Paul also cautions Cessna owners not to grease their flap tracks. They’re not meant to be greased, although the rollers are supposed to be lubricated. Grease Options March 24 2022, David Prizio, Kitplanes: https://www.kitplanes.com/grease-options/#:~:text=If%20your%20plane%20lives%20on,05%20and%20GN%2015%2C%20respectively For a full grease cross reference chart: EMTC https://emtc.aero/wp-content/uploads/2021/01/Mappe2.GREASE-XREF-1.pdf From the LPS product application guide: https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://pdf.directindustry.com/pdf/lps-laboratories/application-guide/11942-89226.html&ved=2ahUKEwjYgbmQiIiOAxVHHTQIHS21OzQQFnoECB4QAQ&usg=AOvVaw0KD4UOmbKMMo-0_4cGPymS Todd has a 2008 Cessna 400 that he just took delivery of. The airframe around the windscreen has a few little cracks that look like spider cracks. He’s read that there’s been an issue with this area and he’s wondering how much it matters. Paul said Todd is seeing cracks in the filler, and the expansion and contraction rate of it is different than the structure, which causes the cracks. Cessna apparently said back wh...

That's one way to flat spot a tire

Jul 15, 2025 41 min

Mike, Paul, and Colleen explain why they almost never set their parking brakes. Plus, valve guide concerns and gotchas on preflight. 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: William wants to know how Mike, Paul, and Colleen do preflight inspections as A&Ps, and if they look at something that most pilots don’t. Colleen said she always checks the last thing she worked on. She suggests to look really carefully at any work that’s recently been completed. Paul mentions the nut and cotter pin on the trim tabs on Cessnas, especially after maintenance. Mike said he worries if the airplane has been moved while on the ground for things like tow limits. Paul also said to check nests, pitot covers, and fuel vent covers for bugs, dirt daubers, etc. Michael is wondering what’s wrong with his parking brake. When he first bought the airplane, the parking break worked to hold the airplane, but wouldn’t release without touching the brakes again. Now, after some work during annual, if it’s anything more than an idle, it won’t hold. Paul said he only ever sets the parking brake to get out and set the chocks. There are only two possibilities, the hosts say. IT’s either mechanically mis-rigged, where the valve isn’t cutting off the line completely, and the other is that the valve is leaking. Paul said the system is simple. You hold the brakes, and the valve pinches off the line. Joey has a Cessna 150 and he does a lot of his own maintenance. About a year ago he had a stuck exhaust valve. A local mechanic did the rope trick to free the valve. He cleaned the exhaust valve guides, although not thoroughly enough. He had planned to do it every 300 hours. He and his wife were flying a few months later, got another stuck valve, and thankfully were able to make a safe emergency landing. He tries to fly very lean, but it happens so often he’s wondering what else he can do. Paul said to defin...

An airplane with no engine is worth nothing

Jul 1, 2025 1 hr 1 min

Oil is everywhere this time, with consumption and temperatures problems for three of our owners. 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: Mark has a Twin Comanche and is loving his new electronic ignition. He has an issue where oil temperature and CHTs are slightly different on one engine than the other. His oil temperature also spiked on one climbout on a hot day, and he’s wondering what’s wrong. He’s using the variable timing. Nothing like this happened prior to the ignition install. Paul suggested that maybe some baffling changed during the install. The hosts narrow in on either airflow or oil flow as the culprit. Colleen said to think of baffling not as trying to direct airflow across the engine, but a system that creates a high pressure, pushing air through the cylinder cooling fins. Chris is wondering what’s wrong with his new engine. He has a Cessna 206 and he put in a new Continental IO-550. After some initial runs, but found that it was burning about a quart of oil per four hours. On one flight is running a bit rough. It had turned out to be a failed magneto. They added an air/oil separator, which obviously didn’t help. He did some low level, high power runs that didn’t seem to help. At 100 hours he did a ring flush on Savvy’s recommendation. The ring flush seemed beneficial. Then after 10 hours he had only burned a quart. They are now at 150 hours and they are at a quart every 4 or 5 hours, and they’ve done another ring flush and it’s burning less oil again. He’s wondering why the rings are clogging up. Mike immediately zeros in on the problem by asking how long Chris has been running straight weight oil. He admits it was 150 hours on the advice of his mechanic. AD oil helps to prevent sludge build-up. Willie is wondering if you need an A&P to do an AMOC, or alternative method of compliance with an AD. The hosts describe the process, which can be co...

You have to cart mogas around like a homeless person

Jun 15, 2025 1 hr 3 min

A Cirrus with fluctuating fuel flow, de-injecting an engine, and fear of overhaul 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 notes below: Joe has a Maule with a 540 engine in it. The company has a mod to turn the engine to a carbureted version and he’s wondering about the legality of something like that. Paul said it happens in the 210 market. Whether it’s a good idea is another issue, the hosts say. Joe is unable to run autofuel is the injected version, which is why he’s interested in it. Colleen said she’d rather have an injected engine than run mogas. David wonders how perspective owners are so afraid of TBO. He has a 182 with an engine that’s nearly at TBO, and people who contact him are afraid of the high time. The hosts discuss strategies for buyers who may be looking at airplanes with engines at TBO. Assuming the engine is running well, a new owner can fly it on that “borrowed time” while they learn and enjoy the airplane. Alternatively, if the engine truly needs to be overhauled, the time down is obviously a concern for a new owner. Mike said he thinks it’s best to buy an airplane with a run-out engine. The price has been discounted for the cost of the engine, the seller is motivated, and worst case you have to overhaul it soon. And every hour and year that you don’t have to overhaul it is “free.” And when it does come time to do the overhaul, you get to do it to your spec. Shalom has a Cirrus that isn’t behaving. If he sets the mixture at lean of peak, the fuel flows start to fluctuate. A few minutes later, it will drop off sharply, and then back quickly. The manifold pressure and rpm stay pretty consistent. He’s changed the fuel pump and the spider. Nothing has helped. Mike said if there’s a constriction in the fuel line between the fuel control unit and the manifold, it can cause oscillating fuel flow and lower flows.

You have license to go zorching around

Jun 1, 2025 1 hr 0 min

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 spra...

"Continentals burn valves and Lycomings stick valves"

May 15, 2025 1 hr 11 min

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 s...

My airplane is a flying experiment

May 1, 2025 1 hr 6 min

It's all engines all the time this episode. Rusty ones, sticky ones, and one that doesn't burn oil. 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: Ralph had to throw away his relatively new engine. His flying club has a 1968 Cherokee 180. They overhauled their engine, and the first annual looked good. On the second annual and after only 100 hours of flying, they had a stuck valve. Digging in they found extensive corrosion. Now past a second overhaul, they want to ensure it doesn’t happen again. The hosts focus on how much (or little) the airplane flew with the new engine. 50 hours a year isn’t much, especially if they weren’t regular hours. An hour a week is great, for example, and something like 4 hours once a month is worse. They advise Ralph use camgard, fly more often, hangar it, and use an engine dehydrator. Adam has a Cirrus SR20 on leaseback to a flight school with only 500 hours on it. A student was taking off, and around 900 feet they heard a bang, and experienced partial power and a loss of oil pressure. Lycoming took the engine back for an inspection. Sticking valves caused it to throw a rod. Mike said Lycomings often stick valves, and it’s something that should be expected. The manufacturer recommends a wobble test per Lycoming Service Bulletin 388C every 400 hours in airplanes and 300 hours in a helicopter. You can go a thousand hours with the new valve guides. Mike stressed that it’s also very important to be trained to detect morning sickness, which is usually the first sign of a valve sticking problem. If a cylinder doesn’t light up with the others on a cold start, or feel rough, it indicates valve sticking and the engine should be shut down right away and examined by a mechanic. Colleen suggests having an eagle eye on the engine monitor during the first startup of the morning. Mike said leaning aggressively, especially on the ground, can also help...

They put all their maintenance records on napkins

Apr 15, 2025 1 hr 2 min

Chris is trying to make sense of his logbooks. He has a Cessna 172 RG and he and his partners had a few electrical issues recently. Some of the logbook entries went in the airframe book and some went in the engine logbook, and he’s wondering about the decision-making process involved in picking the proper logbook. Mike said there’s no requirements around which entry to put in which logbook, and in fact, there’s no requirement to have a logbook in the first place. It’s easier and retains the value of the aircraft, of course, but the need to keep a specific logbook isn’t based on regulation. The reason we use different logbooks, he said, is because if we were ever to sell the engine separately from the airplane, it would be nice to be able to include the record in the sale. If the item would move with the engine, put it in the engine logbook. Paul said his shop only puts the annual inspection in one logbook, and typically that’s in the airframe book. Brandon has a 1977 Cessna 182Q with a low-time engine. Every time he borescopes it he sees lots of lead buildup on the valve stems of the cooler cylinders. He’s wondering if there’s a way to run it hotter, or is there something he can add to the fuel. The hosts agree that it’s actually a mixture distribution issue, something normal and expected in the O-470. Paul had a 182 and he did a bunch of lean testing. When he would lean to roughness and roll it back only enough to smooth out the engine, he would have two cylinders lean of peak, two at peak, and two rich of peak. Mike suggests adding TCP to the fuel. The main downside is that it’s quite toxic, so careful handling is required. Scott is interested in pushing the boundaries of the maintenance regulations. He’s wondering if he is allowed to sign off an AD as an owner because the regs don’t specifically state it has to be a mechanic. Mike thinks it must be an A&P because they are inspections, and only A&Ps can do inspections. There are a few ADs that explicitly allow...

Keep torturing those airplanes...and students

Apr 1, 2025 54 min

John is a maintenance officer in a club, and he is wondering about tire ply ratings. The manual calls for 4 ply, but they often install 6 ply and he’s wondering if that’s ok. The hosts all agree that they have subbed in higher ply ratings when supply dictates. Paul’s rule of thumb is that he always allows a higher ply, but not lower. That’s because the ply rating relates to the weight of the aircraft. Heavier aircraft need higher ply ratings. They get into a discussion on retreads, which can cause issues. They like retreads, but caution that you must ensure they will fit in the wheel well on a retract. Paul worked on a 210 once that caught the skins when retracted. Doug instructs in Aerostars, and he has worked with a number of clients lately who want him to omit the engine-out portion of the training in order to avoid stress on the engines. There’s talk in the Aerostar community about heavy and light cases. Mike said not to worry about the case. Rather, cylinders that rapidly cool are the concern and that’s because the piston and cylinder are different metal densities and cool at different rates, which can lead to scuffing. They all agree the training is important, but pulling the power back slowly, rather than cutting the fuel, will help reduce the risk of engine damage. Paul makes the point that flight schools do this in Seminoles all day, and that he doesn’t hear of widespread issues. Failure isn’t a concern, Mike said. Scuffing is a wear issue. If it’s an issue, Paul said his pistons probably look terrible, but he’s not going to worry about it. He already borescopes regularly. And Mike said he will run an aux tank dry on a long flight. Jason has a Comanche 250 with some electrical issues. Throughout the flight the bus voltage will come down. After landing and taxiing in the voltage climbs back up, and rests around 13.8. Recently after takeoff, the low voltage alarm flashed and went to 10.8 while raising the gear. The hosts think it’s a voltage regulator is...

Shame on you for even thinking about it

Mar 15, 2025 57 min

Should you trade your aging airplane in anticipation of higher repair costs on your current bird? Mike, Paul, and Colleen have a strong opinion on this. Plus, sticky valves, taking good care of turbos, and engine monitor set-up frustrations. 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: Scott has a Tecnam P2010 with a Lycoming IO-390. He’s had a few instances where cylinders dropped off, the engine ran rough, and then they quickly came back on. It was followed by morning sickness. In essence he had a sticky valve. He found that his CHT temperatures were quite low. At altitude, running the airplane at best cruise power, his CHTs are about 350 degrees. In climb if he leans he can get three cylinders over 350. Mike said he wouldn’t stress about the CHTs, but he would borescope the cylinders to verify that there isn’t too much build-up. Yuriy has a new-to-him 2010 Cirrus SR22 that’s turbonormalized and he’s looking for some tips on taking care of his turbos. He flies lean of peak at 28 inches. He is limiting turbine inlet temperatures at 1,500 degrees. Mike thinks 1,500 is excessively conservative. The red line is 1,650 degrees, and Mike tries to keep his at or below 1,600 degrees. He also doesn’t subscribe to the one inch per minute reduction of manifold pressure. Lycoming at one time published a document that said not to cool CHT more than 60 degrees a minute. Mike’s engine monitor alarm is at 30 degrees a minute, and he said it doesn’t go off very often. He also doesn’t cool the turbo on the ground before shutting down unless he had high power right before landing for some reason. Wade has a Cessna 185 with an IO-550. On his last annual he had a few burned exhaust valves. He’s trying to avoid higher maintenance bills in the future. Paul tries to make Wade feel better by telling him that burned valves have nothing to do with how he’s operating the engine and everything to do w...

If that doesn't work you've got the flame thrower option

Mar 1, 2025 1 hr 5 min

Ever wonder how the flap system in a Cessna works? This episode Mike, Paul, and Colleen take a deep dive on the system, plus engine vibrations, leaning for high altitude takeoffs and go arounds, and getting bees out of a restoration. 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: Ken is experiencing vibrations in his Cherokee at certain throttle settings. After installing an engine monitor he discovered that with the throttle at roughly 90 percent full he could induce the vibration, but then quell it by using the mixture. He could see that a cylinder was going offline at full rich, but came back online when leaned. Mike suggests that he needs to lean in the climb to compensate for the overly rich mixture, but Ken said he’s also able to stop the vibration by reducing the throttle setting but keeping the mixture full rich. The hosts still think he’s too rich. They recommend leaning in the climb and keeping the EGT constant as he climbs. Ken also noticed that the cylinder that goes offline is also an outlier on the engine monitor. They tell him to do a GAMI lean test and an induction leak test to try and isolate whether he has a problem or just a poor mixture distribution. Find the test Mike described on Youtube: https://youtu.be/_VfiPuheeGw For more on the induction leak test Paul described: https://www.savvyaviation.com/wp-content/uploads/savvy_pdf/Savvy-Flight-Test-Profile-Expanded.pdf Marcus has a first generation Cirrus and he wants to ensure he is leaning properly for high-altitude takeoffs. Paul said to put his EGT around 1,300 or 1,350 degrees, which will put him close to the Cirrus chart, but is more accurate. For high altitude go arounds, Paul knows his fuel flow at around 1,300 degrees EGT, so he just sets the fuel flow to the expected amount. Luke has been having an issue with the flaps coming down in his 182. What follows is a loooooonnng and detailed description of...

Your airplane is on a full-time IV drip

Feb 15, 2025 1 hr 8 min

Can one high oil pressure reading forever alter your engine? Mike, Paul, and Colleen answer this question, plus the quirks of the O-470, compression test redemption, and repairman certificates. 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: Everett is wondering if his oil pressure is forever altered. He has a Piper Colt with an O-235. The pressure used to be 75 psi, and on a flight the oil temp spiked and the pressured went up to 85 psi. Even after cylinder work, the temperature and pressure have remained high. Paul starts by asking if he’s sure the indications are correct. They suspect a blockage somewhere, although there’s no oil cooler on the O-235. They suggest getting a manual to check for the engine’s entire oil pathway and follow it to see if he can find a blockage. Randall wants to know if the hosts are too hard on compression tests. He asks whether they hold any value. Mike said there’s no harm in doing compression tests, but that one should never change or overhaul a cylinder with compression numbers alone. Knowing where the air is escaping does offer some value, they say. There’s not much you can discover on a compression test that you wouldn’t discover on a borescope inspection that impacts safety of flight, Paul said. Manuel asks how EGT and fuel flow relate on his Cessna 180. He’s seeing a spike in EGTs before they come down again on takeoff. The low compression O-470 will have higher EGTs, especially on takeoff. Mike said Manuel's engine monitor is configured for a carbureted engine, and thus puts a big time delay and smoothing function on the fuel flow. Without the smoothing, the fuel flow would wobble up and down often, making it hard to read. That’s why fuel flow indications rise so slowly after adding takeoff power. And bu slowly adding power, Manuel is delaying the addition of the enrichment function of the carb, which is why he’s seeing a delay for the EGTs...

You don’t know if he’s going to hit you with a wrench or a lawsuit

Feb 1, 2025 1 hr 9 min

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 doi...

There's a serious brain drain in aviation maintenance

Jan 15, 2025 1 hr 4 min

A 182 mysteriously losses power and the hosts struggle to explain why. Plus, basic engine temperature theory, confusing ADs, and why it's so hard to find good help these days. 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: Andrey was flying low and slow on autopilot for a mission when he noticed the airspeed dropping. He saw a drop in rpm, and an increase in manifold pressure. He also saw very low oil pressure. He added power, climbed, and returned to the airport. After landing, he checked the oil level and everything was fine. On a run-up check after talking to his mechanic, the engine stumbled. A new oil pressure sensor seemed to have fixed the issue, but he’s wondering if that’s really what was wrong. The hosts agree that it sounds like Andrey was having two issues because a drop in oil pressure shouldn’t impact engine performance. A big drop, or complete loss, will impact the prop governor, but not in the way Andrey experienced. After looking at the data they wonder if there was also something working through the oil pressure relief valve. Willie has a Cessna 310T and is confused about the exhaust AD. He’s getting conflicting information from mechanics and 310 experts. Mike was involved in the fight surrounding this AD, which is so confusing that the FAA had to issue an SAIB after the AD to explain it further. Yet the community is still confused, with the top Twin Cessna shops divided on when the AD should be complied with. Mike said it’s his opinion that it happen at overhaul. Others believe it’s 12 years. Andy is a maintenance manager and wants to know how to teach troubleshooting skills. Paul said in his experience techs can troubleshoot in their heads, do it via manuals and diagrams, or not do it at all. The process should not be, let’s go change this part and see what happens, he said. It should be, let’s go test something and see what we learn from the result. Relat...

Check it, log it, and then relax

Jan 1, 2025 1 hr 16 min

Can you have a prop strike without a prop? This is one of the more unusual questions the hosts have faced. They also track down a carbon monoxide leak, advise on Continental rpm settings, and help an owner who likely had a pre-ignition event. 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: Robert is an A&P who is trying to help a flight school track down a carbon monoxide leak in a Cherokee. An instructor had a carbon monoxide event, took up a monitor, and found that it was reading at least 300 ppm. The exhaust and heater shroud were replaced, but the cabin was still getting more than 10 ppm. He’s wondering if there is a maximum level allowed in aircraft. Mike said Car 3 didn’t have a maximum, but that Part 23 says 50 ppm is the allowed maximum under current regulations. Hypoxia and carbon monoxide are cumulative, and he said his current comfort is below 20 ppm. He also said leaning impacts CO levels. Peak or lean of peak EGT lowers CO. How it gets in is a bit of a mystery sometimes. He said there was a case where Mooneys with air conditioning were drawing in air from the intake on the side of the airplane. Paul said in a Cherokee it comes in via the forward wing attach point. There is supposed to be insulation to stop it from coming into this area, but over time they are taken out or lost. It’s often not from the engine compartment. It’s through the belly or downstream from the exhaust pipe. John wonders if you can have a prop strike without a prop on the engine. He bought an RV9 with the engine on, but no propeller. He loaded it into the back of a box truck. Stopping partway to check on it, he found the tie-down straps had slipped and the airplane had be banging around in the truck. He’s wondering if he should be concerned, and what he should be checking for. Paul said to put a dial indicator on it and check to make sure it’s less than .005. Some of the bolts on the Van’s prop...

There's a reason they call these amateur built

Dec 15, 2024 59 min

How to identify CamGuard in an oil analysis, erratic idles, how to check the oil, and what the wrong prop does to an engine are on tap for the latest episode. 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: Tan has a 1968 Piper Arrow 180. He has an erratic idle as the engine warms. Mike and Paul said it sounds like maybe sticky valves. He and his mechanic haven’t done the wobble test. It almost can’t be a spark plug, Mike said. Colleen said it could be an ignition harness. Paul suggest he could do an in-flight mag check to help verify. Even though it should start with morning sickness, Paul said it’s not unlikely that it’s a sticky valve. Fuel could also be an issue, as they’ve cleaned the injectors, which Mike, Paul, and Colleen think they induces more problems than it solves. Dicky is concerned about his last oil analysis report. Some of his wear metals are much higher since he’s been using CamGuard, and he’s wondering whether that’s normal. High calcium and high phosphorus are CamGuard’s signatures on an oil analysis, according to Mike. One thing Mike noticed that Dicky didn’t ask about was high silica, indicating dirt in the engine. High silica usually brings high wear metals because the dirt acts to scrub the cylinders. Dicky said he had a problem with his air filter box, and had replaced a part. Enock is trying to settle a flight school debate. He checked the oil and the instructor asked if he screwed the dipstick back in when checking it, or if he just tapped the stick to the top of the tube. Everyone he asked at the school had a different answer. Paul said he screws it back in to check. Colleen agrees. Mike said all the readings should be taken with a grain of salt. He recommends running about two-thirds full. Many type certificate data sheets have a minimum level. And the only somewhat accurate reading is the first one of the day when the oil has time to fully drain ba...

Don't open up the fuel system if you don't have to

Dec 1, 2024 1 hr 3 min

Clogged injectors, how to care for an engine while training, avoiding costly altimeter checks, and engine design considerations are on tap for this episode. Email podcasts@aopa.org for a chance to be on the show. Join AOPA to become a member of the world's largest aviation community at aopa.org/join Full notes below: Marko’s engine had a strong revving sound on takeoff. He saw that he had an EGT above 1,800 degrees and one that was below baseline. A run-up after landing made it seem like it one cylinder wasn’t firing. A borescope inspection revealed nothing unusual. A subsequent check of the injectors found that there was debris in one. His mechanic suggested it was a blocked injector. He’s wondering what would cause that. It turns out this event was soon after the annual when the injectors were cleaned. The hosts agree that the maintenance is clearly what caused the clogged injector. Mike said this is such a delicate operation that he thinks it’s almost as if the fuel system should only be cleaned under sterile conditions. Colleen said she used to clean hers, but now doesn’t because she knows the risks. Paul colorfully describes the problem of cross-contamination. Dylan teaches in a carbureted Seminole and he wants to treat the engines well, and is looking for best practices. He mentions shock cooling, which the hosts quickly debunk. The school’s engines are over TBO and they’ve never had to replace a cylinder. Obviously whatever the school is doing is working. He’s also wondering about failing the engines. Lycoming recommends failing the engine with mixture, but many people like to shut off the fuel. Mike said he wouldn’t worry about shutting the engine down from the fuel selector, and that it shouldn’t introduce air or other issues. Mike worked in the auto industry for many years, and he works on his own airplanes as much as possible. He’s wondering why aircraft engines don’t have ventilated crankcases. Mike said crankcase ventilation is primarily for environme...

The engine didn't explode

Nov 15, 2024 1 hr 2 min

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 podcasts@aopa.org for a chance to get on the show. Join the world's largest aviation community at aopa.org 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 maintenanc...

When they go bad the engine is toast

Nov 1, 2024 1 hr 2 min

Lean of peak is causing odd vibrations in a Commander, and the hosts discuss proper troubleshooting. Plus carb heat on the ground, dehydrators, and parts no longer manufactured. Email podcasts@aopa.org for a chance to get on the show. Full notes below. Chip said his mechanic is concerned about lean of peak because we don’t know the actual temperature at the valve, as the temperature is taken downstream. Colleen makes the point that EGT temperatures are fine because it’s well below the valve limit temperature. Mike said valves burn only when they don’t seat properly. They shed their heat through physical contact with the seat at the cylinder head. They also shed it through the valve stem. Detonation once flying lean of peak isn’t a concern. It’s getting to that point that’s the biggest risk. Paul suggests that once you know the fuel flow at your desired power setting you can lean straight to that fuel flow and not worry about EGT or CHT until it’s set and stable. Chip is also concerned about a vibration in the floor of his Rockwell Commander. Mike suggests he do some testing to help isolate the issue. If it goes away at certain rpms, then it suggests that it’s an engine-based issue. At a constant rpm but with changing pitch, it suggests a potential airflow or airframe source. Frank is questioning the logic of the Luscombe handbook. It says to put the carb heat on for takeoff. It’s also placarded that way on the panel. The hosts can’t figure out why this would be required. The hosts suggest he ignore the handbook and operate as he would in other airplanes, in part because the engine would be breathing unfiltered air while on the ground. Bill has a Cessna 180 on floats with an O-470-50 engine. For the last few months he hasn’t been flying as much and he wants to preserve the longevity of the engine. He is looking for details on engine dehydrators and whether they actually work. Colleen looked through some research and found that those who had done some side-by-side...

It goes through cylinders like flapjacks

Oct 15, 2024 1 hr 0 min

Rough idle, electronic ignition basics, airplanes to avoid (or not), and the difference between detonation and pre-ignition are on tap for this episode. Email us at 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: Stephen wants to get the engine on his Cessna 206 purring. At idle the engine stumbles down to 600 rpm. It never quits, but doesn’t run smoothly either. Mike asks if they’ve done an rpm rise test at 600 rpm. Paul explains it’s part of the installation process of a new engine. You set the engine at a set rpm, then pull the mixture back slowly to get a 25 rpm rise. More than 25 rpm means it’s running rich. Less than 25 rpm means it’s running lean. Engines don’t come out of a crate ready to go. They need to be set up properly. Mike also said that landing with full mixture rich is an issue as well. He said there are only two times you should have full mixture. One is when starting cold, and the other is when applying 100 percent power (at lower density altitudes). Mark is interested in electronic ignition for his 210, particularly the Surefly. Paul loves the Surefly on his airplane. He doesn’t love the advanced variable timing. He thinks a bit aggressive. But it is selectable, so you can turn it off if you like. Mike said he would try it with the variable timing on, and only turn it off if the CHTs are too high. Colleen said her husband has done the dual Surefly on his Legacy. He has higher CHTs, but not unacceptably high. The fuel burn is also lower, but the biggest benefit is easier starting. Erick is looking for any angle to justify buying his first love, a Cessna 337. He would prefer a turbocharged Skymaster. He’s wondering if there’s any hope for the future of these engines being affordable. You must go and buy a turbocharged Skymaster, Mike said. The engines that Mike has previously been worried about are on the pressurized Skymaster. The turbocharged engines are rated at...

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Shock cooling is a myth

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Podcast details

Created by: AOPA
Status: Active
Latest episode: Nov 2, 2026
Episodes: 116
Release period: Every two weeks
Avg. episode length: 55 min
Explicit: No
Language: English

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