c/avionics-technicians

Found a 20-year-old wiring diagram taped inside a panel that saved my whole day

It was in a Beechcraft King Air that came in for a comms issue, and the original tech's notes from 2004 were still there. The note said 'pin 14 on J2 likes to go open,' and sure enough, that was it. Anyone else find these old hidden notes from the previous crew?

Just read a report about the most common cause of avionics faults in small aircraft

I was looking through an NTSB safety brief from last year, and it said that for general aviation, over 40% of avionics-related squawks traced back to bad connectors and corrosion, not the black boxes themselves. That's a huge number. It really hit home after I spent a whole day last month chasing a ghost in a Cessna 172's comm system, only to find green fuzz in a D-sub behind the panel. Makes you think twice before you start swapping out whole units. How often do you guys make connector inspection and cleaning a first step in your fault finding?

Choosing between the old Collins Pro Line 4 and the new Garmin G5000 for a King Air retrofit

Had to pick a full glass cockpit system for a client's King Air 200 in Dallas last year. Went with the Garmin G5000 even though it cost about 40k more, because the training and parts pipeline for the Collins stuff is drying up. It was a steep learning curve for the whole shop, but now we're the go-to guys for Garmin work in the area. Anyone else had to make a call like that on an older airframe?

Serious question, has anyone else had a shop try to make you sign off on a job you didn't fully test?

I was working at a small regional shop in Boise about two years ago. We had a King Air come in for a full Garmin G5000 upgrade, and the lead wanted me to sign the 8130 before we did the final ground check. He said the plane was 'booked solid' and we needed to push it out. I mean, I get the pressure, but I flat out said no. We ended up finding a bad data bus connection that would have caused a blank screen on climb out. How do you guys handle that kind of push from management when you know it's not right?

Found a weird trick for a stubborn LRU fault on a Garmin G1000

Had a Citation in Wichita with a PFD that kept dropping out, but only above 15,000 feet. The book said to replace the whole display unit, but I remembered an old timer telling me to check the backshell pins for cold solder joints. Took the connector apart and found pin 22 had a tiny crack you could only see with a 10x loupe. Reflowed it with my Weller station and the fault cleared. Anyone else fixed a high-altitude fault without swapping the box?

My neighbor's kid asked me why we still use physical manuals on the flight line

He's in high school and said, 'If you can pull up a wiring diagram on a tablet in two seconds, why carry the 20-pound binder?' Honestly, it made me realize I've been doing it that way for 15 years just because that's how I was taught. How many of you have fully switched to digital tech data for your daily troubleshooting?

I tried using a new contact cleaner on a stubborn LRU connector and it made things worse.

The pilot who told me 'just make the warning light go away'

We had a Citation X in for a full panel check in Dallas about 3 months ago. The captain came into the hangar, pointed at a persistent but minor caution light, and said, 'Can't you just put a piece of tape over the sensor? I need this bird in the air by 5.' I had to explain, slowly, that the sensor was tied into the bleed air system and ignoring it could lead to a cabin pressure issue at altitude. He just shrugged and walked off. It really stuck with me how some people see our job as just making problems quiet, not actually fixing them. Anyone else had a pilot ask you to basically bypass a safety system?

I visited the Museum of Flight in Seattle and saw a vintage radio rack restoration.

The wiring harness was completely hand-soldered with cloth insulation, no modern connectors in sight. Has anyone here ever had to work on something that old, and what was the biggest headache?

Spent $400 on a 'universal' wire crimper that ended up wrecking my connectors

I bought this fancy crimper online because the ad said it worked for every aviation connector type, but it mangled the pins on three D-sub connectors before I gave up. That was $400 down the drain and a whole afternoon wasted re-pinning everything by hand. Anyone know a solid crimper that's actually good for MIL-DTL-38999 series connectors?

Warning: a pilot's offhand comment about static completely changed how I check antennas

I was doing a post-flight check on a Cessna 172 last week and the pilot mentioned he'd been getting some weird static bursts on comm 2 during climb out. He said it was 'like someone keying the mic for a split second, but nobody was there.' I was ready to just swap the radio, but then he added, 'It only happens above 3,000 feet when it's dry out.' That made me stop. I spent an hour checking the bonding straps on the VHF antenna mount instead. Found one behind the baggage area that looked tight but was actually just making contact on one side of the washer. Cleaned it up, put on a new star washer, and torqued it to spec. The pilot flew it yesterday and said the issue is gone. It hit different because I almost wasted time and money on a part that wasn't broken. How often do you guys actually get useful troubleshooting hints from the flight crew?

Spent 8 hours chasing a phantom voltage drop on a G1000 system

Had a King Air in the shop with a PFD that kept blanking out. Traced it to a 0.3V drop on a 28V power feed, but the wiring looked perfect. Turns out, a tiny bit of green corrosion inside a cannon plug pin was the culprit, and my meter probes weren't making good contact at first. Who else has lost a full day to something that simple?

Chatted with a retired A&P at the Oshkosh airshow about troubleshooting

He told me 'the manual gives you the path, but your meter tells you the story,' and it clicked that I was following steps without really reading the data. Anyone else have a simple rule that changed how you approach a fault?

I was convinced my coax crimps were fine until a test flight in Tucson

The pilot reported intermittent comms, and my meter showed a perfect connection. A senior tech asked if I'd ever done a proper VSWR check under load, which I hadn't. How many of you actually run that full check on every antenna install?

Just realized my quick fix for a static discharge issue made things way worse

I was working on a G1000 system in a Cessna 172 last week and kept getting random resets. I figured it was static from the dry air, so I sprayed the whole panel with anti-static cleaner. The resets stopped for about an hour, then the whole PFD went dark. Turns out the cleaner left a film that messed with the internal ribbon cable connections on the display unit. I had to pull the unit, clean every pin with isopropyl, and reseat it. Has anyone else had a 'fix' backfire because of a chemical you used?

I was at the Pima Air and Space Museum last weekend and saw something in the old avionics bay that made me think

They have a B-52 cockpit section you can walk through, and I was looking at the old analog instrument panel. It's wild to see how much wiring and how many individual gauges they had to manage, all for systems we'd now handle with a few digital displays. It really hit me how far the tech has come, but also how the basic idea of routing signals and keeping things powered is still the same job. Has anyone else been to a museum lately and noticed something that made you appreciate the modern stuff we work on?

Showerthought: A loose connector in a Cessna 172 taught me to trust my meter over the manual

I was troubleshooting a nav radio in a hangar in Boise, and the book said to check voltage at pin 4. My Fluke showed zero, but the pin looked fine. I finally wiggled the whole D-sub backshell and the reading jumped. Ever had a manual point you to the wrong spot entirely?

I thought those cheap fiber optic testers from the online marketplace were junk until a hangar fire drill.

We had a surprise drill at the Phoenix base last month and the main comms line went down, so I grabbed a $40 tester from my bag as a last resort. It pinpointed a broken splice in the overhead cable run in under two minutes, saving us a huge headache. What's one tool you doubted that actually saved your skin on the line?

Update: I just logged my 500th hour on the new Garmin G5000 trainer and I think the hype is wrong.

My old boss from the Dallas shop called me about a 737 autopilot fault

He said he spent two days checking the flight control computer before he found a single corroded pin in a cannon plug under the cockpit floor. He told me, 'We always chase the big black boxes, but half the time it's just a bad connection.' That really stuck with me. How many hours do you think we all waste not checking the simple stuff first?

Just hit 5 years without a single write-up for a wiring error

It's a weird thing to track, but it really made me think. On one side, it shows good habits and careful work. On the other, it makes me wonder if I'm just lucky or if the pressure to never slip up is too high. How do you guys balance speed with perfect quality on complex harnesses?

Just changed my mind about the Fluke 87V after hitting 500 continuity checks without a single false beep on a stubborn harness.

I always thought the audible continuity was just a basic feature, but this meter's filtering is so good it saved me from chasing a dozen ghost shorts in a noisy avionics bay.

Appreciation post: The weirdest thing I keep seeing with D-sub connector pins

I swear, every time I'm helping a new tech at our hangar in Tampa, they're trying to seat those tiny pins with a flathead screwdriver. It's like a rite of passage that goes wrong. I've seen three guys in the last two months bend the same pin on a 37-pin connector for a nav system, turning a 20 minute job into a half day of ordering parts. The proper insertion tool costs maybe 15 bucks. What's the strangest 'shortcut' you've had to un-teach someone on the line?

After seeing three techs in our hangar skip the avionics cooling fan check on pre-flights, I'm convinced we're setting ourselves up for a costly inflight failure.

One guy told me 'if the radios work on the ground, the fan's fine,' but I pulled the logs on a Citation that needed a $15,000 LRU swap after a fan seized and cooked the box during cruise last year, so what's the right call here?

Just realized a corroded ground strap under the floor panel of a Citation XLS was the real culprit for a phantom autopilot fault that took me three entire days to trace.

Has anyone else had a sneaky ground issue cause a cascade of weird faults that made you chase your tail for that long?