Airplane Owner Maintenance - By Dean Showalter

254 – Solving an Air Conditioning Mystery and Learning New Things!

This experience was a good one! (At least looking back in 2020 hindsight.) We had to dig deep to fix this one! I was about to give up and started thinking it might be time to take the airplane somewhere else for troubleshooting and repair. Thankfully Richard, our chief pilot, didn’t give up so easy and he encouraged us to dig deeper before giving up. With the guidance of “Smitty,” an air conditioning expert at Stevens Aerospace in Greenville, South Carolina, we troubleshot and fixed a problem with our King Air 350 air conditioning system. He told us we could access the center floor area just aft of the cockpit and ground pin #25 in the circuit board labeled “N1 SPEED / R ICE VANE SENSE” and this would fool the airplane into thinking the right engine was operating, so that we could troubleshoot the air conditioning compressor on the right engine. We followed Smitty’s directions. But after grounding pin 25 and powering up the system with the GPU, we found no voltage at the air conditioning compressor wiring plug. (We disconnected the red plug above the compressor to check for power to the plug.) He then had us remove the right inboard wing leading edge to check the pressure switch in the high pressure line. This was not the problem. Smitty also told us there was a resistor and also a zener diode in the circuit. During the process, my friend and coworker at Classic Aviation, David Kihlmire, said, “I think we should remove “that panel” referring to the side cowling panel on the right engine, just forward of the area where the air conditioning compressor was located. And I’m glad he said that! Here’s what we found: The bottom wire was broken off the resistor! Take a closer look: After soldering the wire back onto the resistor, there was now power to the air conditioning compressor clutch, and we were confident the system was fixed. David attached the gauges to the servicing ports in the nose gear well, and we ran the right engine… and YES! The system operated normally. When it was all said and done, it was truly a team effort, and a great learning experience. And it was perfect timing to get the air conditioning fixed, because Summer time and warm temps are right around the corner! Be sure to listen to the audio for this episode to hear the air conditioning story, and also my story about playing “Banana Grams” with my wife and daughter, as well as a story about repairing an oil leak on my Grasshopper lawnmower. I wasn’t sure I wanted to tackle this oil leak myself, but after calling around and discovering all the lawnmower repair shops are backed up for weeks, I decided to go to YouTube University and face the challenge. It was a 2 1/2 day project, among other things, but I got it fixed! I had to remove the engine and disassemble it to replace the front crankshaft seal: It was a mess behind the flywheel: Lots of cleaning and a new crankshaft seal did the trick, and it’s back in business! I’m grateful because one time mowing with the push mower was enough for me to realize I don’t want to do that every time! All these experiences reminded me once again how worthwhile it is to take on challenging projects, even if they are difficult. I hope you are encouraged to tackle something difficult in your life, if it’s something you’re interested in but might feel overwhelming. Go for it! The post “254 – Solving an Air Conditioning Mystery and Learning New Things!” appeared first at AirplaneOwnerMaintenance.com

253 – Missed Windows of Opportunity

This morning I felt the inspiration to record a podcast episode… I got my hotel room set up with my computer and my microphone, and there it sat. I missed the window of opportunity… for whatever reasons, I did not record. And this afternoon, the inspiration was fading away. And then I remembered something. Often in the past, I’ve found that exercise is not only good physically, but it’s also good mentally and emotionally as well. So I went down to the exercise room and ran some miles on the treadmill and did some pushups. And it worked. When I arrived back in my room, I seized the opportunity and recorded some thoughts about missing windows of opportunity, learning from them, and continuing on. If you listen to the audio for this podcast, you’ll hear about the following: How I finally got today’s episode recorded. A missed window of opportunity for a timely departure at Chicago O’Hare. A young man named Alex who I met at a Cleveland airport. Hope you enjoy the episode! And remember, don’t get bogged down in the missed windows of opportunity behind you… Instead, look for the open windows of opportunity in front of you now, and go for it! And if you have a story to share, please click the button over on the side of the website and leave me a voice message… I’d love to hear from you.

252 – Why Does the Bonanza Gear Relay Breaker Pop?

(If you’re in a hurry, scroll down to see the tiny little chafed wire that caused this whole conundrum.) Now here’s the story… This landing gear relay breaker had been popping intermittently: It came time for annual inspection and we decided to replace the breaker with a new one, in order to rule out a faulty breaker, and attempting to minimize long and frustrating labor for troubleshooting. Good thing, because as it turns out, there was a loose screw in the landing gear motor breaker next to this one, which would not have been discovered if we had not replaced the relay breaker… check out the loose screw: It was obvious some arcing had occurred due to the poor connection: Unfortunately, tightening the screw in the 30 amp motor breaker, and installing a new 5 amp relay breaker, did not fix the problem. Back up on jacks for more troubleshooting: Todd, the airplane owner, posted in BeechTalk about the situation, and we got some good feedback. Meanwhile, I took a good look at the wiring in the main gear wells, especially the squat switch wiring… no issues found. So I called the American Bonanza Society (I love their tech support, and it always reminds me of the exceptional value of being an ABS member, even as an A&P/IA.) Curtis Boulware discussed the wiring diagram with me and pointed me to some things to check: Disconnect the C1 terminal from the gear relay and test… nope, it’s not that: Disconnect plugs in gear wells and test… nope, it’s not that: There’s a circuit board located under the copilot panel above the right rudder pedal: Aha! Now we were getting closer. After removing the circuit board from its mounting position and disconnecting the P1 plug, the relay breaker no longer popped when gear was selected up. But why? I was beginning to wonder if we would need to have the circuit board repaired or replaced… and who knows how much one of those would cost! And then my eyes landed on something that did not look quite right. It was a spot on a tiny little wire. After closer examination, sure enough, this little wire had chafed through the insulation and some of the internal strands of copper wire were visible: But what had it been chafing on? Finally, I saw it… a burnt spot on the sidewall of the airplane: Perhaps this wire had been chafing for many years and finally wore through the insulation. (The little loop of wire had not been adequately secured into the wire bundle, which allowed it to touch against the aluminum sidewall of the fuselage.) It was the little G43A20 jumper wire that connects 2 pins in the P1 plug. After removing the bad spot in the wire, splicing it back together, and securing the wiring, the landing gear system worked perfectly. And if you’re curious like me, here’s a peek inside that circuit breaker under the copilot panel near the outboard rudder pedal: I’m glad we didn’t have to replace that thing! (To hear the full story on this one, be sure to listen to the audio for this podcast episode.) The post, “252 – Why Does the Bonanza Gear Relay Breaker Pop?” appeared first at AirplaneOwnerMaintenance.com

251 – Bennett’s Exhaust Valve Rescue on his Cessna TTx

Bennett contacted me awhile back to see if I could lap an exhaust valve for him. The #4 exhaust valve showed a very uneven appearance when viewed with his borescope. Bennett flew in to KSHD one morning and we got started. Before lapping, we checked the cylinder compression and it was 29/80… not good. Here’s what the valve looked like: We got to work and lapped the valve. When we were happy with the progress, we reinstalled the exhaust valve in the valve guide and installed new valve springs and a new rotocoil, to help ensure the valve would rotate properly and provide the best possibility for a good seal between the valve and the seat. After running the engine, we rechecked the compression, and were very pleased… it was 74/80! Amazing! But there’s more… Several weeks later, Bennett emailed me, and here’s what he said: “Dean, I am so excited I am emailing from my hangar… Looks like lapping worked great! After one flight down to Florida and back… about 3.5 hours each way, the #4 exhaust valve looks vastly improved. See before and after pics attached. Much thanks!” And here are the before and after photos he sent: BEFORE: AFTER: (and keep in mind the following photo was after only about 7 hours of engine operation.) I’m confident this exhaust valve has been rescued, and will quite possibly run normally for many more hours. It’s always nice when we can solve these valve problems with “laparoscopic surgery” (lapping a valve in place) instead of “major surgery” (removing a cylinder.) There’s more to this story, but I’m not going to type it out here… you can listen to the audio for this podcast and hear about the magneto issues we solved on Bennett’s engine as well. (The magnetos on Bennett’s engine are challenging to work on due to their location and all the stuff around them, but with some persistence, it’s doable.) Thanks Bennett, for flying down to SHD. It was nice meeting you and working with you! The post, “251 – Bennett’s Exhaust Valve Rescue on his Cessna TTx” appeared first at AirplaneOwnerMaintenance.com

250 – Frustrations with Piper Rudder Cable Tension

If you look closely in the photo above, you can see my friend Chris, smiling. It was the day he arrived at Classic Aviation (KSHD) to begin his annual inspection with me. Chris is not only an airplane owner and pilot, but he’s also a certified airplane mechanic as well. I was very happy to have him help with the process as much as possible. As I worked through the inspection, I found the control cable tensions needed some adjustment, including the rudder cable tensions. As I began to tighten the left and right rudder cable tensions evenly so as not to disturb the rigging, I encountered a problem. The left cable turnbuckle bottomed out in the turnbuckle barrel, and there was no more ability to tighten the cable, but I had not yet reached the cable tension spec in the maintenance manual of 85 pounds, plus or minus 5. Yes, this is a high tension, but it is what the manual says. You can listen to the audio for details of how we resolved the issue, and how I got help from my friend Kenneth who previously worked at Classic Aviation. The short story is that we went through extensive rigging of the nose gear steering system, the rudder pedal bars, and the rudder cables, and finally got things set, with 80 pounds on the rudder cables. When the annual was completed, we had fixed a bunch of other items as well, and hopefully Chris will be good to go for another year with no maintenance interruptions, as much as possible. He even sent me some photos of the day he flew his sons down to the Outer Banks of North Carolina and visited the Wright Brothers Memorial! Thanks Chris! The post “Frustrations with Piper Rudder Cable Tension – Episode 250” appeared first at AirplaneOwnerMaintenance.com