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 concern, not an engine damage concern.

<description>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 concern, not an engine damage concern.</description>

Fuel indication problems, high oil temps, gear motors, and corrosion

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 concern, not an engine damage concern.

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

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 service of all the airplane’s components. That makes it easy for inspection, replacement, and for ADs. Mike’s records include a big Word doc that includes all his maintenance records and a spreadsheet with the weight and balance, equipment list, and so on. Paul suggests only giving your maintenance provider a thumb drive so they can’t hold your logbooks hostage, nor do anything else you don’t approve of. Then when you’re ready to leave, you get the thumb drive and the sticker to go in the logbook when you get home. 
 
Paul read an article that advised against leaning too quickly and leading to washboarding of cylinders. Mike thinks that came from an old service bulletin. He said it needs to be taken in context. They were talking about heating the cylinder too fast. They weren’t talking about the transition from rich of peak to lean of peak, but rather a very rich mixture to a slightly less rich mixture. The piston heats faster than the cylinder barrel, and it expands faster than the cylinder. The piston could potentially cause metal to metal contact.

<description>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 service of all the airplane’s components. That makes it easy for inspection, replacement, and for ADs. Mike’s records include a big Word doc that includes all his maintenance records and a spreadsheet with the weight and balance, equipment list, and so on. Paul suggests only giving your maintenance provider a thumb drive so they can’t hold your logbooks hostage, nor do anything else you don’t approve of. Then when you’re ready to leave, you get the thumb drive and the sticker to go in the logbook when you get home. 

 

Paul read an article that advised against leaning too quickly and leading to washboarding of cylinders. Mike thinks that came from an old service bulletin. He said it needs to be taken in context. They were talking about heating the cylinder too fast. They weren’t talking about the transition from rich of peak to lean of peak, but rather a very rich mixture to a slightly less rich mixture. The piston heats faster than the cylinder barrel, and it expands faster than the cylinder. The piston could potentially cause metal to metal contact.</description>

Spark plugs, aircraft records, lean of peak, and circuit breakers

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 service of all the airplane’s components. That makes it easy for inspection, replacement, and for ADs. Mike’s records include a big Word doc that includes all his maintenance records and a spreadsheet with the weight and balance, equipment list, and so on. Paul suggests only giving your maintenance provider a thumb drive so they can’t hold your logbooks hostage, nor do anything else you don’t approve of. Then when you’re ready to leave, you get the thumb drive and the sticker to go in the logbook when you get home. 

 

Paul read an article that advised against leaning too quickly and leading to washboarding of cylinders. Mike thinks that came from an old service bulletin. He said it needs to be taken in context. They were talking about heating the cylinder too fast. They weren’t talking about the transition from rich of peak to lean of peak, but rather a very rich mixture to a slightly less rich mixture. The piston heats faster than the cylinder barrel, and it expands faster than the cylinder. The piston could potentially cause metal to metal contact.

"Being an aircraft owner is the hardest job in aviation"

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.
 
Johann has a Cessna 210 that has a hot cylinder. He's gone over the baffling, which helped, but he's wondering what else to do. Paul tells Johann to throw fuel at the problem. He sets the fuel flow a half-gallon to one gallon over the book number, advising that you'll know you've done too much if it runs rough at takeoff. With Johann's intercooler, he recommends even more. Because intercoolers bring more dense air into the engine, you have to adjust the fuel flow, although the manufacturer doesn't say how much. So it takes some trial and error. Paul also advised Johann to look at his engine mounts and considering installing an aftermarket prop. On the 210 a tight tolerance between the spinner and the cowling can greatly reduce temperatures. If the spinner is low you can raise it with new mounts or spacers under the front mounts.

<description>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.



Johann has a Cessna 210 that has a hot cylinder. He's gone over the baffling, which helped, but he's wondering what else to do. Paul tells Johann to throw fuel at the problem. He sets the fuel flow a half-gallon to one gallon over the book number, advising that you'll know you've done too much if it runs rough at takeoff. With Johann's intercooler, he recommends even more. Because intercoolers bring more dense air into the engine, you have to adjust the fuel flow, although the manufacturer doesn't say how much. So it takes some trial and error. Paul also advised Johann to look at his engine mounts and considering installing an aftermarket prop. On the 210 a tight tolerance between the spinner and the cowling can greatly reduce temperatures. If the spinner is low you can raise it with new mounts or spacers under the front mounts.</description>

Keeping cool (and warm), plus oil composition and lean of peak

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.



Johann has a Cessna 210 that has a hot cylinder. He's gone over the baffling, which helped, but he's wondering what else to do. Paul tells Johann to throw fuel at the problem. He sets the fuel flow a half-gallon to one gallon over the  book number, advising that you'll know you've done too much if it runs rough at takeoff. With Johann's intercooler, he recommends even more. Because intercoolers bring more dense air into the engine, you have to adjust the fuel flow, although the manufacturer doesn't say how much. So it takes some trial and error. Paul also advised Johann to look at his engine mounts and considering installing an aftermarket prop. On the 210 a tight tolerance between the spinner and the cowling can greatly reduce temperatures. If the spinner is low you can raise it with new mounts or spacers under the front mounts.

"That's an urban legend"

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 bring an aviation alternator to an automotive rebuild shop with aviation parts, they recommend against a straight automotive version. 
 
Mark has a Cherokee 235 and he likes to take videos of his flights in order to critique his skills. One one night flight he saw flames coming out of his exhaust, which he obviously found alarming. The hosts put his mind at ease, telling him it's a natural by-product of the combustion process, and simply represents the power his engine is making. But they dig further to find out two important points. First, Mark doesn't have a flame cone on his exhaust. If he did, the flames probably wouldn't be visible. And two, this only happens when he's lean of peak. This intrigues Mike because it's evidence of a slower combustion process that's known to happen during lean of peak. He surmises that because the process is longer, but the rpm consistent, combustion isn't complete when the valve opens, which is why Mark only sees the flame.

<description>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 bring an aviation alternator to an automotive rebuild shop with aviation parts, they recommend against a straight automotive version. 



Mark has a Cherokee 235 and he likes to take videos of his flights in order to critique his skills. One one night flight he saw flames coming out of his exhaust, which he obviously found alarming. The hosts put his mind at ease, telling him it's a natural by-product of the combustion process, and simply represents the power his engine is making. But they dig further to find out two important points. First, Mark doesn't have a flame cone on his exhaust. If he did, the flames probably wouldn't be visible. And two, this only happens when he's lean of peak. This intrigues Mike because it's evidence of a slower combustion process that's known to happen during lean of peak. He surmises that because the process is longer, but the rpm consistent, combustion isn't complete when the valve opens, which is why Mark only sees the flame.</description>

Flaming exhausts, lean of peak, and unnecessary maintenance

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 bring an aviation alternator to an automotive rebuild shop with aviation parts, they recommend against a straight automotive version. 



Mark has a Cherokee 235 and he likes to take videos of his flights in order to critique his skills. One one night flight he saw flames coming out of his exhaust, which he obviously found alarming. The hosts put his mind at ease, telling him it's a natural by-product of the combustion process, and simply represents the power his engine is making. But they dig further to find out two important points. First, Mark doesn't have a flame cone on his exhaust. If he did, the flames probably wouldn't be visible. And two, this only happens when he's lean of peak. This intrigues Mike because it's evidence of a slower combustion process that's known to happen during lean of peak. He surmises that because the process is longer, but the rpm consistent, combustion isn't complete when the valve opens, which is why Mark only sees the flame.

"More time to fly, less time to turn wrenches"

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.
 
Tim is wondering how many times to cycle the propeller during the run-up checks. The hosts all agree that once is sufficient, unless there's a need to do more. That might be because the oil is very cold, the hub is large, or there wasn't a good response on the first try. But all the parameters that need to be checked can be done in one pull, and a second and third pull are unnecessary and cause unneeded strain on the engine.

<description>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.

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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.



Tim is wondering how many times to cycle the propeller during the run-up checks. The hosts all agree that once is sufficient, unless there's a need to do more. That might be because the oil is very cold, the hub is large, or there wasn't a good response on the first try. But all the parameters that need to be checked can be done in one pull, and a second and third pull are unnecessary and cause unneeded strain on the engine.</description>

How to cycle the prop, cam spalding, and inop parts

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.

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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.



Tim is wondering how many times to cycle the propeller during the run-up checks. The hosts all agree that once is sufficient, unless there's a need to do more. That might be because the oil is very cold, the hub is large, or there wasn't a good response on the first try. But all the parameters that need to be checked can be done in one pull, and a second and third pull are unnecessary and cause unneeded strain on the engine.

"You have a lot of splaining to do" 

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.

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