Special announcement: We have more pictures of Mike’s airplane, but first, I want to let you know about a Zoom call I’ve scheduled for tomorrow.
I’m hoping to provide a way to get together online for some aviation encouragement in this weird time we’re in with the Corona Virus and the effects of it. Here are the details for tomorrow’s call:
Time: Mar 28, 2020 03:00 PM Eastern Time (US and Canada)
If you’d like to see some pictures of things I’ve been working on, and how it has looked at our airport this past week, along with some encouragement to keep moving forward in this time, then please join me tomorrow on the call!
If it works out well tomorrow, we might have another call again soon.
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Now back to Mike’s Piper Stinson…
Listen to the audio for today’s episode to hear the fascinating story of how Mike and Sasha White acquired their favorite airplane, and named her “Charlie!”
The freshly overhauled Franklin engine is in pristine condition!
The tail has a very distinct design:
There’s even some beautiful wood interior reminiscent of Charlie’s rich history:
The cowling trim is also a sight to see:
Charlie’s instrument panel sports the beautiful red paint to match the exterior:
… and the leading edge slots provide excellent slow speed and stall characteristics:
All in all, this is a very cool airplane!
I had no idea there was such a thing as a “Piper Stinson.” Thanks Mike, for educating me!
I discovered just today Mike has a special tail hoist he built to lift the tailwheel off the floor for cleaning the belly… real craftsmanship!
So… perhaps the next time Charlie rolls up to the ramp at KSHD, I’ll get to meet the whole crew… Mike and Sasha, and their little Yorkipoo, Bocce!
Yesterday, I had an opportunity to present a talk at our local IA renewal seminar about exhaust valve borescoping.
I shared some of my favorite pictures – the ones that demonstrate how critically important borescoping is, and that compression testing alone is not sufficient.
The following three examples are especially startling, since they showed a compression test of at least 60/80, but were in imminent danger of in-flight failure:
The FIRST ONEis from a Continental engine in an A36 Bonanza. Notice the green area at 9:00, indicating that area was in danger of a piece breaking off the edge.
The SECOND ONEis from another Continental engine, also an A36 Bonanza. The compression of this one was 61/80, but there was a chunk missing from the edge, with a crack toward the center of the valve!
The broken edge still had enough area to seal for a compression test:
And the THIRD ONE was from a Lycoming engine in a Cessna 152. Take a look:
In the previous three examples, the borescope was absolutely necessary to discover these dangerous and unairworthy exhaust valves.
For comparison purposes, the following two pictures are examples of healthy exhaust valves:
I also shared some pictures of valves that other people have removed from their engines.
The following is from Sylvan Martin’s Grumman Tiger with a Lycoming O-360 engine. Sylvan was able to land safely after his engine ran slightly rough. He said, “My opinion is that cylinder 1 would have been noticeable at a minimum of 150 hrs before it deteriorated to the point of cracking that far across the face… Compression check will help w/ ring problems, but our family’s experience in industrial diesels (power generation) is that rings fail slowly/predictably while valves fail suddenly/catastrophically…..”
He later had to change two other cylinders, after the borescope indicated they were burning:
(Previous three photos courtesy of Sylvan Martin.)
Jason Figueroa had to change a cylinder on his Cherokee 235’s Lycoming O-540 engine due to a burning exhaust valve that was found with a borescope.
(Photo courtesy of Jason Figueroa.)
Jason said, “Borescoping told us we had an impending problem, and led to catching it before it failed.”
Here are two more exhast valve pictures from an unidentified source:
I’m convinced this broken valve could have been detected with a borescope LONG BEFORE the edge broke off.
My hope is that all of us who have the responsibility of determining the airworthiness of piston engines in airplanes, will use a borescope along with the compression tester for higher levels of safety and reliability.
Do you have a dream to fly? If so, you might be encouraged by the poem I shared at the end of my talk yesterday. My daughter sent it to me one day last Summer… it’s called, “The Dream Does Not Die!” If you’re interested, be sure to listen to the last part of the audio.
Engine oil leaks are a common problem on small airplanes with piston engines. But how much oil leakage is too much? Here’s an indicator: If there’s oil on the nose tire, and it paints a stripe on the pavement with each revolution, that’s too much oil leakage.
This was the case the other day on a Cessna 172, so we did some detective work to see where the oil was coming from.
After removing the cowling, it was obvious the oil leak was significant, and it appeared to be coming from the left side of the engine.
Here’s what we discovered about the rocker oil return line on cylinder #4:
The wire that holds the engine baffles in place under cylinders 2 and 4, had cut a hole in the bottom of the rocker cover oil return line. When the engine is running, this line continuously returns oil from the rocker arm area back to the crankcase. With engine vibration, this is a common area for chafing to occur, and is an important area to inspect.
Here’s a closer look at the oil line after it was removed. The spiral wrap was a previous attempt to prevent chafing, but the wire still cut through the line.
After removing the spiral wrap, the chafed area was clear:
It doesn’t take a very large hole to make a big oil mess!
This story reminds me of some helpful principles for evaluating engine oil leaks:
If engine oil is dripping on the nosewheel, it’s probably not normal and needs to be checked.
If something changes, check it out. Example: engine breather tubes sometimes drip after shutdown, but if you notice a dramatic increase, make a further investigation.
When troubleshooting oil leaks, go to the highest point on the engine where you see oil. Oil can run down on lower components and lead to wrong conclusions about the source of the oil leak.
Verify all connections and fittings are tight.
Listen to the audio in today’s episode to hear about some other loose fittings that recently caused problems… one on a Piper Turbo Arrow, and one on a Piper Saratoga.
After a successful career in computers early in life, Carl Valeri decided years ago it was time to pursue his passion for aviation. Since that time, he’s been an airline pilot, flight instructor, aviation careers coach, mentor, Piper Cherokee pilot, and many other things.
Carl is well known as the host of two podcasts, the Aviation Careers Podcast, and the Stuck Mic AvCast. You can find him in both of those places:
In today’s episode, we talked about all kinds of fascinating things, including:
Carl’s background and how he got into aviation.
How he was hired years ago as an airline pilot, and furlowed the same year, in 2011.
How his struggle served to prepare him for what has become one of his greatest passions… “Helping people move forward with their aviation career.”
What the acronym “CAMEL” means to an airline pilot… I had never heard this before, and I thought it was really cool.
Carl’s current opportunity to lease and fly a Piper Cherokee… the 12th Cherokee to come off the line years ago.
The maintenance issues he’s encountered recently with the Cherokee.
And since this is the Airplane Owner Maintenance podcast, it’s only appropriate that we document this part with some pictures.
ISSUE #1: Smoke in the cockpit! Apparently somebody forgot to tighten an oil line!
The oil made a mess on the cowling. And upon closer examination, the source was identified – the rocker oil return line B-nut had come loose. When the oil dripped down on the hot exhaust, it produced smoke that made its way into the cockpit.
Solution and reminder: Always double check engine fluid lines and hoses, and apply torque putty to the B-nuts.
ISSUE #2: Fuel leak. Carl told us about a leak that showed up under the airplane on the left side. Listen to the episode to hear his advice about how to communicate with your A&P about issues like this.
It turned out the leak was from his “gascolator” or fuel strainer. Here are the parts from this ancient piece of technology… just like you might have seen on your grandpa’s tractor!
In this situation, Carl made the wise decision to upgrade to a “Steve’s Aircraft” gascolator, a much better design with increased reliability and ease of maintenance. Take a look:
ISSUE #3: Exhaust leak. Carl noticed some abnormal discoloration at the cowling seam.
It turned out there was a significant leak at one of the exhaust sleeve transitions in the engine compartment.
This situation is a little different than many Cherokees, since this particular engine was installed with an STC.
ISSUE #4: Electrical problem. With the benefit of 20/20 hindsight, Carl was able to recognize how the airplane had been showing some warning signs of this issue… be sure to listen to the audio to get the details.
What seemed like a complex problem in the beginning, turned out to be a blown fuse.
Sometimes the little things can make a big difference!
In spite of the maintenance challenges, Carl still loves to fly the Cherokee. I think one reason why is because he shares his love for aviation with others:
In telling about his aviation adventures in life, Carl is quick to acknowledge that, “I could never have done any of that without the help of others.” Now, he’s “paying it forward” in so many ways to help those who are coming behind him.
And finally, to finish up with a little humor: “Even an airline pilot who flies jets, recognizes there’s something missing in the following picture!
Carl, thank you very much for pushing all of us to keep moving forward and appropriately pursue our aviation dreams! We appreciate you, and I sure am glad flying still puts a smile on your face!
“There’s no RPM drop when I select left mag, and if I turn the ignition switch off, the engine continues to run.”
That’s what the owner of this Cirrus reported when he arrived at our airport the other day.
One of our technicians got to work to troubleshoot the problem. Here’s what he found:
The magneto P-lead wiring checked good.
The ignition switch checked good.
It appeared the problem was with the magneto.
So let’s pause and ask, “Which magneto, left or right?”
Good question, because this stuff can sometimes be confusing.
When the pilot got no RPM drop when selecting left mag, it likely means the ability to ground (or turn off) the right mag has been lost. So even though we are selecting left mag, it’s the right mag that actually has the problem.
And sure enough, that’s exactly the case here… upon removing the point cover from the right mag (which also contains a capacitor with a stud for the P-lead attachment,) we determined with an ohm meter check that the capacitor in the P-lead circuit had failed in the open position, making it impossible to ground (or turn off) the right magneto.
The point cover along with the capacitor, mounts to the magneto as seen on the left side of the following picture:
The new capacitor has been ordered and the Cirrus should be flying again real soon. You can hear the full story in today’s podcast episode.
The other P-lead story in this episode is from an A36 Bonanza I’m inspecting. This is a very different situation… this one had some chafing P-leads in the engine compartment that were a problem-in-the-making. Take a look:
After pulling the wires down a bit, the worn areas became really obvious:
These wires have 4 layers:
An inside center wire (the actual P-lead.)
A layer of insulation on the center wire.
A layer of braided shielding to prevent radio noise.
An outside layer of insulation.
Thankfully, the inside wires (P-leads) were still protected… if those inside wires had shorted to ground, the magnetos could have failed to operate. If the P-leads are shorted to ground by touching the airframe, it’s the same effect as turning the ignition switch off.
Here’s one last picture of the P-leads with some context of how they are attached to the magnetos:
So… any time you’re working in the engine compartment, whether for an oil change, or anything else, it’s a good idea to look around for any signs of chafing… sometimes you might be able to avoid a future in-flight problem by catching the issue early.
I was sitting in my car that day, having lunch with my friend Matt, when we noticed the airport fire trucks were rolling out toward the runway. Although they exercise these trucks regularly, this time seemed different.
And sure enough, a Piper Navajo made a low pass and it was obvious the landing gear was not extended. I decided to go inside and try to find out what was going on.
After some conversation with the unicom people, I offered to talk with the pilot. They gladly agreed.
Thankfully, we had maintained several Navajos in the past at Classic Aviation, so I was reasonably familiar with the landing gear system. I spoke with the pilot on the radio, and confirmed he was able to extend the gear with the emergency extension hand pump, and the gear selector handle had returned to neutral, with all three gear down lights on.
This seemed promising, and we anticipated an uneventful landing. A low pass confirmed the gear now appeared to be extended.
A successful landing was a relief to everyone.
After landing, the nose baggage compartment was opened, and it became obvious the hydraulic fluid in the power pack was very low… apparently so low the engine driven pump could not pump the gear down.
Here’s where a good understanding of the system is helpful.
There is a “standpipe” in the hydraulic power pack that has a unique function. If the fluid level gets too low, the standpipe reserves enough remaining fluid for the emergency hand pump to pump the gear down. It’s a great safety feature in this airplane, and others with hydraulic landing gear.
We filled the power pack with MIL-5606 aviation hydraulic fluid, and recommended the pilot get the system checked for leaks.
Listen to the audio for the complete information on this one, but the main lesson is “Be familiar with your retractable landing gear system, especially the emergency procedures.”
Here are a several suggestions to make this happen:
Practice your emergency landing gear extension procedure, in flight, with a competent and knowledgeable instructor or pilot, at least once a year.
Visit your maintenance shop during the annual inspection and operate the emergency gear system with the airplane on jacks.
Watch the gear operate on jacks, from outside the airplane, so you can have a visual picture of what is actually happening when you retract and extend the landing gear.
Memorize your landing gear emergency procedures, and keep the manual/checklist in a convenient and accessible location in your airplane.
Finally, make sure your landing gear system is well maintained and properly adjusted, with full hydraulic fluid (if applicable) to ensure safe and reliable operation.
Note: scroll to the bottom of this post for a special announcement.
Have you ever experienced an inflight magneto failure? If not, you might some day… but if you take action on the recommendation in today’s episode, you can dramatically reduce the likelihood of that happening.
The left mag on this Cessna 172RG failed in flight, and after opening the mag, it became obvious what happened.
The finger electrode that is part of the distributor gear inside the magneto, had gotten loose from its mounting position, and was able to rotate freely 180 degrees, while still occasionally resting in its proper position, which made it somewhat intermittent. Take a look:
The finger electrode should stay firmly in it’s mounting point as in the following picture:
The LAA, or Light Aircraft Association, put out an excellent, one page Airworthiness Alert February 21, 2019, about this very issue. Here’s a link for that document:
The bulletin recommends changing the copper electrode in certain Slick magnetos to a monel electrode, which is much stronger. This is definitely a worthwhile service bulletin to comply with for the affected Slick mags.
Now back to the Cessna 172RG… it also needed a new ignition switch kit. The Gerdes ignition switch is subject to AD 93-05-06 which requires inspection and lubrication each 2000 hours, although I sometimes wonder if this interval is frequent enough. Take a look at the carbon tracking and wear inside the ignition switch:
This condition can cause the switch to malfunction… it’s easily remedied by installing an A-3650-2 Ignition Switch Kit, which includes replacement of this contact plate, as well as the 3 contact cups in the switch housing. Notice the difference between the old cups and the new cups… any contacts that have the silver plating worn off, must be replaced… most of the switches I’ve inspected, have needed a new kit.
Replacing the switch plate is fairly simple, but slightly tedious, by transferring one wire at a time, from the old switch plate, to the new one:
The second story we talked about in today’s episode is about an inflight magneto failure in an Aerostar. The pilot did some excellent inflight troubleshooting, and landed safely after determining the right engine left mag had failed, and was able to fly to a safe destination with the right engine selected on right mag only.
So after today’s episode, I have several tips about magneto troubleshooting:
When you select one mag, if the engine immediately runs rough, it’s most likely a spark plug issue.
When you select one mag, if it’s a more smooth, but large RPM drop, it may be a magneto problem.
When you select one mag, if the engine dies immediately, it might be a mag, or a shorted P-lead, or the ignition switch, (the switch being the most unlikely, in my opinion.)
Causes of ignition system troubles, in the order of likelihood:
Spark plug issues.
Magneto issues.
P-lead wiring.
Ignition lead, or corrosion in magneto attachment.
Ignition switch.
In fact, I seriously wonder if both issues talked about in today’s episode could have been avoided. I don’t have information on the 172RG’s magneto, but the Aerostar’s failed magneto had about 1000 hours since overhaul.
Find a reputable magneto shop, and keep your mags in tip-top condition.
My favorite magneto shop to recommend is Aircraft Ignition Services LLC, operated by Kevin and Leah Herrington in Honey Grove, Texas. They’ve been doing excellent work for us at Classic Aviation LLC. Check out their website:
Announcement: Carl Valeri is the host of the Aviation Careers Podcast and the Stuck Mic AvCast. He recently interviewed me for an episode of each of these shows (ACP255 and SMAC229), and it was so inspiring to talk with him. You can find these here:
During the recent annual inspection on Drew Wright’s Cessna 182, cylinder #1 had a low compression of 42/80. However, with the amazing technology of borescoping, he was able to take a look inside the cylinder. The nice concentric circle of deposits on the face of the exhaust valve indicates a healthy valve. Drew wondered if perhaps this valve would be a good candidate for lapping in place, without removing the cylinder.
Even though the valve appeared healthy, Drew noticed a significant amount of air leaking out the exhaust during the compression test. Once again, his borescope was very helpful in observing the condition of the exhaust valve and seat area. The valve looks good, except for the rough and uneven seating area.
The seat also looks good, except for the corresponding rough and uneven seating area.
With the supervision of his A&P, Drew was able to remove the rocker cover and the exhaust valve springs. After verifying the valve guide was in good condition with no excessive wear, and the valve was sliding freely in the valve guide, he was ready to “lap” the valve (to apply a small amount of valve grinding compound to the edge of the valve using a long Q-tip through the top spark plug hole, and spinning the valve against the seat to smooth out and improve the seating area.)
Drew used a piece of wood dowel rod, some clear tubing, and some hose clamps, for this task… I like his idea so much, I’m planning to use this technique in the future.
One of the most important parts of the lapping process, is cleaning out the residue after the job is finished. One method is to spray Av-gas into the top spark plug hole to wash the grinding compound off the valve and the surrounding areas, and let it run out the bottom spark plug hole. Multiple washings, along with some compressed air, cleans up the area very well.
An additional thing Drew did was to push a thin cloth into the top spark plug hole, and pull the valve back to squeeze the cloth between the valve and valve seat. Then, he could turn the valve against the cloth and clean the seating area even better. I’m also going to keep that little tip in mind for my next lapping project. Thanks Drew!
The seating area of the valve showed a nice smooth band after the lapping was done – very impressive!
After the lapping was completed, a new rotator was installed on the exhaust valve, everything was reassembled, and the compression immediately improved!
But the best result was the compression test that was done after running the engine… that same cylinder that was 42/80, now had a compression of 78/80! What a fantastic result, and now, hopefully that cylinder will run reliably for many more hours.
Be sure to listen to the audio for this episode for more details about Drew’s adventure. He also shared about an induction leak that was visible because of some blue fuel staining.
After removing the intake pipe, it was obvious the gasket had shifted out of position during the assembly process many years ago… perhaps this was part of the poor idling problem that was also corrected during the annual inspection. After installing a new intake gasket and adjusting the idle mixture setting, the engine idled much better than before.
Drew’s story is a true inspiration in so many ways.
So, if you, as an airplane owner, have an interest in learning and getting involved in the maintenance, just find an A&P who is willing to give you some supervision to keep things legal, and you’ll have all kinds of possibilities.
Well done Drew, on your exhaust valve lapping project! I’m thrilled with the result you achieved on this one!
Drew has a young family, and it makes me happy to know he’s taking such good care of his airplane… after all, he’s got some precious cargo to haul around!
Limited time offer on the “Safety Wire Like A Pro!” video tutorial course: (Offer good until midnight December 24, 2019. Just use code “2019” at checkout.)
Hey, check out this 10 second video of an absolutely startling fuel leak I found this past week during a “routine oil change.”
The reason I put that “routine oil change” in quotes is because I’m convinced we should never view an oil change as just a routine thing in itself.
Rather, it should be viewed as an opportunity to become a detective and find any other issues that might need attention in the surrounding area, especially in the engine compartment… like a fuel leak.
Notice the blue staining in the following pictures… clues of a fuel leak:
Apparently, the gasket on this fuel screen plug was hardened and brittle, and no longer able to provide a good seal.
Listen to today’s podcast episode to hear the story about this fuel leak, and how it was solved.
Also, notice the safety wire on the fuel screen plug in the video… it’s in a very tight spot that’s really difficult to work in. It was a bit of an ordeal to even get the safety wire off the plug to remove it.
And reinstalling the safety wire was even more challenging… which reminds me of something I want offer you:
Between now (Saturday, December 14) and Christmas eve, December 24, 2019 at midnight Eastern Standard Time, I’m offering a 10% discount on the safety wiring video tutorial course, “Safety Wire Like A Pro!” This course will teach you everything you need to know to perform excellent safety wiring during preventive maintenance on your airplane.
Whether you’re changing the engine oil, cleaning fuel screens, or safety wiring a brake caliper after changing a tire, there’s a detailed video in this course to help you with that task.
Become a safety wiring expert with this detailed training opportunity. It’s like I’m right there with you at your airplane… you can set your laptop on a table by your airplane, play the appropriate video, and do your safety wiring right along with me, as you watch me in the video… it’s like having your own personal instructor right beside your airplane.
So don’t settle for that ugly, loose safety wiring that I too often see on airplanes… instead, take advantage of this valuable resource and become a safety wiring expert!
Whether your airplane has a “Brackett” brand filter like the first picture, or a “Donaldson” brand filter like the second filter, or another brand like “Challenger” or something else, they all need to be clean and in good condition.
The air your airplane breathes is critically important. Your engine, your vacuum instruments, and even other components, all need to breathe fresh clean air in order to function properly.
Listen to today’s episode to hear about induction filters, vacuum system filters, and even an obscure filter you may not have thought about.
Take a look at what can happen when a Brackett filter is not changed often enough. Upon removal, the foam filter crumbled apart.
Brackett filters have an expiration date on the package… while they work very well when they’re in good condition, they can also fall apart when they are expired. Don’t install an expired filter!
Vacuum systems also need clean filters. Check out this vacuum regulator filter that is covered with dust… this thing has been here for years! Compare this with the new filter that needs to be installed. This filter is sometimes overlooked at the annual inspection. The part number is B-3-5-1. Or, if you buy a Rapco filter, it’s RAB-3-5-1.
The vacuum inlet filter is also an important one to keep clean, so that your vacuum instruments, like the attitude indicator and directional gyro, can breathe nice, clean air. Here’s an example of an old, dirty vacuum inlet filter, compared with a new, clean one:
Clean air filers are vitally important!
Another obscure filter I encountered recently was on an Aerostar 601P. This airplane has a Sandel SN3308 electronic HSI. The internal lamp needs to be changed at regular intervals. Upon removing the unit from the instrument panel, I discovered the fan filter in the bottom of the tray was falling apart. Take a look at the view from under the instrument panel, and how little was left of the foam filter:
The fan pulls air in through the bottom of the instrument tray, for cooling.
It’s a bit of an obscure air filter, but still an important one.
A call to Sandel was very helpful. Although the new filter is a fairly thin, coarse mesh piece of foam, it actually has a part number, and the price was reasonable ($8.) Check it out in the following picture:
The HSI is now breathing clean air again.
So… whether it’s an airplane’s induction filter, a vacuum system filter, an instrument filter, or some other filter, it’s important for all these filters to be clean and in good condition.
Take a look at your filters, and make sure your airplane is breathing nice clean air. Your engine, your vacuum system, and your instruments, will thank you in the form of reliable performance 🙂
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