Episodios

  • "You have license to go zorching around"

    "You have license to go zorching around"
    Jun 1 2025
    An owner wants to fly his engine after it sat for 7 years. Plus, prop strike at the shop, lean of peak, and break-in trouble. Email podcasts@aopa.org for a chance to be on the show. Join the world's largest aviation community at aopa.org/join Full episode notes below: Rupert is having trouble breaking in his new cylinders. They have five hours and the temperatures are still trying to go above 420 degrees on departure. They’ve checked fuel flow and baffling. In a twist of irony he is causing his cylinders to run too hot because the break-in is being prolonged because he won’t run the engine hard enough. Paul said Comanche’s have notoriously have poor baffling, which can also compound the problem. They recommend running it hard for a few hours and not to worry about the temps being around 420. Craig has a Pitts that was damaged on a high-power run-up after his annual. The tail came up and hit the prop. He’s wondering if there’s something else they should inspect since the case is going to be open. His crank is subject to an AD. The associated service bulletin requires replacement if the case is opened, but the AD does not. He said the insurance has agreed to replace the crankshaft anyway. They said other than close cylinder inspections, it sounds like he’s fully covered. Larry was finding that the lean of peak indication on his Dynon would show that he was lean of peak before the cylinders were actually there. He found a short paragraph in the manual that says if he changes the horsepower percent rating, it works fine. He also describes a procedure in the Dynon that basically recreates the GAMI lean test. Mike describes how Savvy does the AI engine modeling. The amount of air or fuel going into the engine will be the limiting power factor. In rich of peak, fuel is abundant, so air is the limiting factor. In lean of peak, fuel is the limiting factor. Dave last ran his engine 7 years ago. He mixed oil and camgard, put it into a pressurized tank, and sprayed it under pressure into every place he could. He’s changed desiccant plugs, and had a dehumidifier running as well. If he has pitting he’s wondering if it’s dangerous to fly. Paul said airplanes don’t fall out of the sky because of pitting on the camshaft, and Mike added that they do fall out of the sky after taking off cylinders to look for signs of corrosion. Either the engine will make metal in the filter or it won’t, he said. If the filter is clean for the next 100 hours he dodged a bullet. Nothing that could be wrong corrosion wise is a safety of flight item. It’s a safety of wallet item. Paul said he would recommend changing the oil soon after running it. If the cylinders don’t look corroded the bottom end probably isn’t either, Mike said. Paul suggests he crank the engine with one set of plugs inoperative until he gets an oil pressure indication, and then start it normally.
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    1 h y 1 m
  • "Continentals burn valves and Lycomings stick valves"

    "Continentals burn valves and Lycomings stick valves"
    May 15 2025
    Valves are sticking all over as the hosts give advice on how to avoid pulling cylinders. Send your questions to podcasts@aopa.org for a chance to be on the show. Join the world's largest aviation community at aopa.org/join Full notes below: Rick has a 182 with a new Pponk engine and he’s burning lots of exhaust valves. He’s wondering what he should change operationally. Paul said to borescope more frequently to find the asymmetric burn patterns before they need to be replaced, and if they start to have asymmetric patterns to lap them immediately. He recommends borescoping every 100 hours. Mike gives some initial results of Savvy Aviation’s borescope initiative, which after 100,000 images found that 7 or 8 percent of valves showed signs of heat distress. Twenty five percent of the engines had at least one valve that was heat distressed. About 85 percent of those valves were in the early stage of distress and could be lapped. Only about 15 percent were considered late stage. Brad has an SR22 with an IO-550 that had high oil usage. They pulled a cylinder, rehoned it and put on new rings. Later he started asking questions about torquing the through bolts, and the shop told him they held a wrench on the other side, but didn’t torque both sides. He’s wondering if he should go back and retorque the bolts. Mike and Paul think he’s probably ok. Bruce is sick of sniffing gas fumes. They installed new fuel senders and a digital fuel gauge in their 172. They followed the procedure to calibrate the fuel senders, but he’s having trouble getting it correct. He’s as much as two gallons off from what it should be. Paul starts by asking what bucket Bruce is using because the utility buckets from the home stores are unreliable as calibrated containers, he said. The other issue is the wet wing construction, which can lead to dams that make it difficult to fully defuel or refuel. Bruce has even accounted for temperature. He’s within half a gallon on one side, which Paul said is usually as close as you can get it. Ed is stirring the pot. He read that in an article in the American Bonanza Society publication that operating lean of peak is bad for engines. Obviously the hosts disagree, and a discussion of the merits of rich of peak and lean of peak ensues.
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    1 h y 12 m
  • "My airplane is a flying experiment"

    "My airplane is a flying experiment"
    May 1 2025
    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. Adam asks if Lycoming’s recommendation to run the engine up before shut down in order to clean the valves actually does so. Mike thinks it’s just inconsiderate of those around you, and maybe not terribly helpful. Jason runs mogas on his Cessna 182. Last year he was climbing through about 8,000 feet and the engine started to stumble. He added carb heat and a few other things, but the engine seemed to come back to life on its own. His Savvy account manager said it was probably vapor lock. Mike agrees with the account manager that the airplane was exhibiting vapor lock symptoms. He thinks it’s possible that a fuel line might be close to the exhaust or something else is warming the fuel before it gets to the carb. Paul suspects it might be the fuel line to the JPI engine monitor transducer. They recommend wrapping it the fuel lines in fire sleeve to see if that improves the problem. Thad has a 1977 Cessna 182Q. He had the engine rebuilt in 2021 and since then it has been “a rockstar.” He thinks it might burn too little oil. It’s only burning about a quart every 50 hours. It makes more chromium and aluminum than the lab is happy with. He wonders if the lack of fresh oil is somehow concentrating the contaminants. It’s possible he’s not getting enough lubrication on the cylinders, Mike said. The chromium can only come from the rings and the valve stems. Usually the problems with the valve stems come combined with increased nickel because they are made of an alloy. Mike said the aluminum in his report is ok, although slightly high. Thad said they’ve borescoped the cylinders and everything looks good. There’s still cross-hatching on the cylinder walls. The hosts are intrigued, but Mike thinks it’s faulty thinking. They debate how much metal stays in suspension though the process of adding quarts. Mike suggests keeping an eye on the filter, but otherwise to keep flying.
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    1 h y 6 m
  • "They put all their maintenance records on napkins"

    "They put all their maintenance records on napkins"
    Apr 15 2025
    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 the owner/operator to perform them. Paul suggests that a lot of ADs require a maintenance action that is outside the scope of owner-performed maintenance as well. Mike is questioning Continental’s guidance that limits extended running below 2,300 rpm. He finds that his airplane runs smoothest at 2,100 rpm. Mike explains that the bulletin came about after an issue with Cape Air and their 402s. After a few in-flight engine failures, they grounded the fleet and started inspecting engines. The failures were caused by counterweight release with accelerated wear in the pins and bushings. Continental couldn’t find anything wrong with the parts, and they guessed that it was due to operation at low rpm. Cape Air was operating at high power, rich of peak. They never tracked down the real problem, and guessed this was the issue. Cape Air had gone from operating at 2,300 rpm to 2,200 rpm. Mike believes that if you are operating at high power and rich of peak, it might be worth observing the limit, but if you are operating at low power, or lean of peak, you can ignore it.
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    1 h y 2 m
  • "Keep torturing those airplanes...and students"

    "Keep torturing those airplanes...and students"
    Apr 1 2025
    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 issue, where it works when cold but not warm. Paul said he thinks of voltage as an indicator of whether the system is working and the amps as an indicator of how hard it’s working. It should be around 13.8 or 14 when working properly. Colleen said she had an electrical issue where her JPI would go offline when she would cycle the gear. Under the panel she found that there was a loose connection on the shunt, causing high resistance. Jason’s issue could be at the circuit breakers, voltage bus, voltage regulator, or any number of places. One way to easily troubleshoot is to see if he can find anything hot by running his hands along the wires. Or look for discoloration, Paul said. Steve writes in asking about oil coolers. During his recent engine overhaul the shop asked if he wanted a congealing or non-congealing oil cooler. Congealing is bad, he thought, so he elected to go with non-congealing. But he lives in Arizona and he’s found the engine runs a bit hotter with a higher oil temperature in long climbs. He’s wondering if he made a mistake. Non-congealing oil coolers have a solid line running through the middle that passes warm oil through the cooler at all times. Mike thinks it’s possible the non-congealing has less cooling capacity because it has less surface area.
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    55 m
  • "Shame on you for even thinking about it"

    "Shame on you for even thinking about it"
    Mar 15 2025
    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 with the lead in avgas. Going through his operating technique, the only suggestion they have is for Wade to lean much faster, and avoid using the lean find feature. The green arc on his manifold pressure gauge is also wrong. He was worried that he’d have to take off at partial power in order to stay in the green arc on the gauge. The hosts discuss how to reprogram the display. Matt doesn’t want to throw good money after bad. He’s wondering how long you should hang on to an airplane as it ages. He has a 1977 Cessna T210. Parts are starting to get scarce. It’s hard to find qualified mechanics. He feels like he wants a great airplane that lasts him well into the future. The hosts all agree that it’s better to hold on to the airplane he knows, and not to worry about 210 parts availability, at least when compared to other airplanes.
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    58 m
  • "If that doesn't work you've got the flame thrower option"

    "If that doesn't work you've got the flame thrower option"
    Mar 1 2025
    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 the Cessna flap system. Blythe was restoring his family’s Cessna 150 and found a bunch of mud daubers. The inspection panels allowed him to clean out some, but he assumes there are more that he couldn’t reach. Paul said the potential corrosion is a key to the solution. He said the bees don’t like to build nests on corrosion inhibitors. He also said to make sure to check up the vertical stabilizer, which is a popular spot. Mike said he’s had luck with moth balls in other machinery.
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    1 h y 5 m
  • "Your airplane is on a full-time IV drip"

    "Your airplane is on a full-time IV drip"
    Feb 15 2025
    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 coming down. Marty is trying to understand repairman certification limitations. He’s done some work on his prop, magnetos, and so on, and he wants to make sure it’s all been legal. Mike said as he understands it, you basically have unlimited authority to do what you want on your airplane. The common sense rule applies, which is to get a demo or some instruction before you do it for the first time.
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    1 h y 9 m
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