Airplane Owner Maintenance

A Maintenance Oriented Podcast For Airplane Owners, Pilots, and Mechanics

Month: June 2023

227 – Electrical Chaos When the Landing Light was Turned On

June 24, 2023 /

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This Bonanza had a problem in the landing light wiring circuit. All kinds of weird things were happening when the light was turned on in flight. You can listen to the podcast audio for more details on this squawk.

I removed the induction filter cover and the landing light assembly and inspected the wiring.

It turned out the landing light power and ground wires were chafing against each other… probably over a very long period of time. Take a look at the area of concern in the red circle on the following photo:

At first glance, it wasn’t visually obvious there was a problem.

But after separating the power and ground wires, it became very clear what was happening. As the internal strands of the power and ground wires began to just barely make contact with each other, the short-to-ground situation started wreaking havoc in the electrical system. The following photo shows the areas where the insulation was worn all the way through to the internal wire:

Sometimes there was static over the comm radio, sometimes the TCAS and intercom would cycle power off and back on, and sometimes the landing light circuit breaker switch would flip off.

I repaired the wiring and secured it really well with ty-wraps and silicone to prevent further chafing. Now Brad will be able to use his landing light any time he wants and be confident it will perform normally.

Vibration from piston engines can create some bad situations! It’s always a good idea to take an extra minute or two to look around the engine compartment whenever you’re in there, like at the oil change, or some other maintenance event, like cleaning spark plugs.

Another interesting squawk on this same Bonanza was a burning exhaust valve and corresponding low compression. The borescope revealed the classic appearance when the valve is not sealing well against the valve seat. Take a look:

I had lapped this valve at the last annual inspection and installed a new rotocoil to help ensure it would rotate properly, so when it still showed an appearance of a burning valve a year later, I figured we would likely need to remove the cylinder and send it for repair.

However, the Bonanza owner uses Savvy Aviation to manage his maintenance on the airplane, and the borescoping experts at Savvy thought it would be worth lapping the valve again to see if it could be saved.

I was happy to give it a second try. I lapped the valve heavily this time and finally, I was satisfied. I installed a new rotocoil again, and after running the engine, I rechecked the compression, and was super happy to see that it was 74/80!

I feel 90% confident that when the next annual inspection rolls around, this valve will have returned to a normal appearance. I’ll be curious to see how it turns out.

All in all, it was a good annual inspection, and Brad should be good to go for another year of flying!

The post “227 – Electrical Chaos When the Landing Light was Turned On” appeared first at AirplaneOwnerMaintenance.com

226 – Piper Lance Lands at SHD After In-Flight Electrical Failure

June 17, 2023 /

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It was a beautiful Tuesday morning at KSHD, and we had the maintenance hangar door open with a good view of the runway. A nice, red and white Piper Lance made a perfect landing on runway 5. As the airplane taxied up to the ramp, I thought, “It would be nice to meet that guy, whoever he is.”

Momentarily, he was standing in our shop, asking if we could help with an electrical issue. It turned out Merle was a super nice gentleman, and he had flown in with his brother, Dave, and their colleague Ron. They were on their way to Pennsylvania that morning, but made a precautionary landing at Shenandoah Valley because of the electrical failure.

I was eager to help. I grabbed my multimeter and hopped in the airplane. When I tried to start the engine, all I got was a small and very feeble attempt to turn the engine and prop. The battery was too weak to run the engine.

I remove the cowling and got access to the alternator. After removing the field wire from the field terminal on the alternator, I turned the master and alternator switches on and verified there was battery voltage at the field wire. I was then satisfied the voltage regulator was working fine, and the problem was likely in the alternator or the wiring circuit.

I then measured the resistance between the alternator field terminal and ground, and at first I got a resistance reading, but when I moved the prop a bit, I had no continuity. There should be a resistance reading, maybe around 6 ohms, give or take a little, for a 12 volt alternator. At this point, I was 90% sure the alternator was bad.

We started searching, and found a local parts supplier had an overhauled alternator, and also one that was “as removed.” Merle opted for the overhauled one, and one of our guys made the short drive to pick it up.

Unfortunately, that alternator had a crack in the bolt hole for attaching the alternator belt tension arm.

We ended up overnighting another overhauled alternator in, and got them going the next day.

It was great meeting these guys! Merle, Ron, and Dave… if you’re ever passing through again, stop in and say hi, and maybe we can go grab a burger at the Old School Burger bus down at the Valley Pike Farm Market.

On a totally different subject, I also talked in this podcast episode about an Aerostar trip we made to Wisconsin this week… not much of an FBO at this little airport near Lake Geneva, WI.

Be sure to listen to the episode to find out about an interesting phenomenon I learned about on the return trip… a momentary harmonic vibration in the clouds.

That’s all for this episode!

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225 – Obscure ATC Intersection Mystery Solved (It’s UDIYU!)

June 9, 2023 /

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And the winner is… Ben Moroze!

Recently, in podcast episode #223, I asked for help in identifying an ATC intersection we flew over on our way into Dulles Airport, (KIAD) awhile back.

I remembered it sounded something like “you-dee-ah” or something similar. Maybe something like “UDIYA” except that’s not it.

Well, Ben emailed me after listening to episode 223, and he correctly identified the intersection as “UDIYU” and told me it’s on the DOCCS THREE arrival and also on the GIBBZ FOUR arrival.

Thank you Ben! You’re the first one to respond after listening to episode 223.

Then, I sent an email out yesterday morning and received a good handful more responses about the intersection, UDIYU.

A big thank you to all of you who responded to this email!

You can listen to the audio podcast for this episode to hear about all those responses.

I also received a couple photos from my good friend Clark, showing the position of the UDIYU intersection… here’s one of those:

Thanks Clark, for the photos!

And here are a couple of my screen shots to get more context for the arrivals with the UDIYU intersection:

And thank you to ALL OF YOU GUYS who responded to my question… it’s really fun to learn about these obscure situations with you.

Now… I’m off to the shop to work on a Bonanza… and be sure to tune in again in a future episode to hear what I found in this Bonanza’s landing light wiring circuit that was causing all kinds of strange and weird effects in other systems as well.

Have a fantastic weekend!

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224 – Jim’s Exhaust Valve Rescue on his Cessna 182 Engine

June 2, 2023 /

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Recently, I received an email from Jim Janaitus, owner of a Cessna 182. He told me the story of lapping an exhaust valve on his engine because the valve showed signs of burning even though the compression was still in the high 60’s. Take a look at the appearance of the valve before lapping:

The area from about 12:00 to about 3:00 is the bad area, indicating the valve is not seating well in that area.

Jim lapped the valve and installed a new rotator. I was super happy when he said, “It went better than I imagined.”

Here’s a follow up photo of the same valve about 12 flight hours later:

Isn’t the improvement remarkable?!

It’s not perfect, but it’s MUCH BETTER than before, and Jim has an excellent plan to monitor the condition of this valve every 20 hours or so.

Well done Jim!

Be sure to listen to the audio for this week’s podcast to hear this story, along with some other weird electrical issues I’ve been sorting out on a Bonanza and on a Cessna 210.

Have a great week!

The post “224 – Jim’s Exhaust Valve Rescue on his Cessna 182 Engine” appeared first at AirplaneOwnerMaintenance.com

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