c/avionics-technicians

Warning: A loose ground strap on a Cessna 172 in Flagstaff almost cost us a whole nav system.

TIL my old boss was right about the 10 minute rule for fault finding

I was talking to a guy who used to run a shop in Mobile, and he said if you can't find a fault in 10 minutes, you need to step back and check the basics again. I always thought that was dumb and rushed, but last week I spent 45 minutes chasing a phantom comms issue on a G1000. I finally stopped, went back, and found a loose ground strap on the airframe side of the firewall I'd skipped. It was right there. Has anyone else had a simple rule like that actually save them a ton of time?

Hot take: I used to fight with old wiring diagrams for hours before a job

I'd print out the whole book and highlight things with three different colors, which took forever. Then a guy at the shop in Mobile showed me how to use the digital overlay tool in our main software, and now I can isolate just the circuit I need in about two minutes. Anyone else have a trick that saved them from a paper nightmare?

Rant: Overheard a pilot in Denver say all our gear is just 'expensive toys'

I was grabbing coffee at the FBO in Denver last week and this captain was telling his FO that our test sets and analyzers are just overpriced gadgets. He said, 'You guys just plug in boxes and follow the lights.' It really got me thinking about how little some crews understand the actual system knowledge and troubleshooting we do. What's the most clueless thing you've heard someone say about our job?

A total blackout at the hangar in El Paso taught me to always carry a backup light source.

We lost all power during a night shift, and my headlamp died right as I was tracing a wire bundle. Now I keep a small, high-lumen pen light in my pocket every single shift. What's your go-to backup light for those dark panel moments?

Got my first solo sign-off on a 737 autopilot rig at the hangar in Tulsa last Tuesday.

Had to pick between a $300 crimper and a $80 one for a big harness job on a King Air. Went with the cheap one.

Warning: That $40 'universal' crimper from the tool truck is junk

Bent three pins on a D-sub connector before I gave up. Had to redo the whole harness, cost me about two hours. Anyone have a solid crimper brand that actually holds up?

My old boss told me to never trust a 'no fault found' on a G1000 autopilot without checking the harness first

I mean, I was working on a King Air last month and the pilot wrote up intermittent altitude hold drops. The log had a 'no fault found' from another shop. I spent a whole day running system checks and found nothing. Then I remembered what he said, pulled the panel, and wiggled the main harness bundle behind the MFD. Sure enough, altitude hold cut out. Found a chafed wire in the bundle that was shorting against a bracket. Fixed it in about an hour. Has anyone else had a specific piece of advice that saved you from chasing ghosts?

Watching new guys skip the continuity check on a simple wire run

I saw a kid fresh out of school at the hangar last week. He was replacing a nav light wire and went straight to power after the splice. No meter, no tone, nothing. That used to be the first thing you learned, back when we had actual paper manuals for a 737-200. I've seen it cause a 3 hour delay on a C-check because a pinched wire took out a whole bus. My old boss in Wichita would have you redo the whole run if you missed that step. What's the one basic habit you see people forget now?

Visited the Pima Air & Space Museum last month and got to poke around a stripped C-130 cockpit

Found an old FAA advisory circular that changed how I think about wire routing

I was digging through some digital archives for a different issue and stumbled on FAA AC 43.13-1B, Appendix A. It has this whole section on wire bundle bend radius that I'd never really paid attention to. It says the minimum bend radius for a wire bundle should be ten times the diameter of the bundle, not just a 'gentle curve' like I was taught. I checked a harness I'd just installed on a Cessna 172, and my bend was maybe six times the diameter. It's a small thing, but it explains some intermittent faults I've chased on other jobs. Anyone else have a 'standard' they learned was actually wrong?

Spent $600 on a fancy circuit tracer and it was a total waste

I bought the ProTech 9000 last year thinking it would save hours chasing wires in tight panels. Used it twice on a Citation X at our hangar in Dallas. The signal bled everywhere, giving false readings on parallel runs. Ended up doing the old continuity check with my Fluke anyway. Anyone have a tracer that actually works on shielded bundles?

Just realized I fixed a weird autopilot fault by checking the harness routing

Working on a Citation in Wichita, the autopilot kept dropping out during climb tests. I traced it for hours before noticing the main avionics harness was rubbing against a hydraulic line bracket, wearing through the shielding. Re-routed it with some extra chafe guard and the fault cleared right up. Anyone else had a gremlin turn out to be simple chafing?

Just read a report from the NTSB about a 2022 incident at Denver International

The preliminary finding said a faulty ground power unit connector caused a full avionics bus reset during pushback. It wasn't in the maintenance logs because the ground crew just swapped the GPU and moved on. Has anyone else run into a similar ghost fault from ground equipment that didn't get written up?

I tried using a cheap thermal camera on a comms box and it showed me something I missed

Last week, I was chasing an intermittent fault on a Garmin G1000 system in a Cessna 172. The autopilot kept dropping out. I had my Fluke meter out and was checking all the usual suspects, but nothing. I remembered I had this little $300 Seek thermal camera I bought online a while back. I figured why not, and just scanned the avionics bay while the system was powered up. One of the LRUs in the back corner was running about 15 degrees Celsius hotter than all the others. Turns out, a bad solder joint on a power supply board was causing a tiny short, heating up just that one spot. I never would have found it without seeing that heat bloom. Has anyone else had a simple tool point them right to a problem like that?

Showerthought: I looked up the actual failure rate for a common connector and the numbers were not what I expected

I was reading an old FAA report from 2018 about in-flight faults. It said that for a specific, widely used D-sub connector in a certain avionics bay location, the primary cause of failure wasn't corrosion or vibration, but bent pins from repeated ground handling. The report claimed bent pins caused over 60% of the faults for that part. I always thought environmental factors were the big issue. Has anyone else seen data that changed how you approach a routine check?

Working on a Citation's autopilot in a hangar in Wichita, I finally got why torque specs matter.

I was putting the pitch servo back in and just went by feel, like I always did. The thing flew fine for a week, then the pilot called about a slight, constant roll. Found the mounting bolts were just a bit loose, letting the whole unit shift. The manual said 35 inch-pounds, which I'd always skipped. Tightened them to that exact number and the drift was gone. Anyone else have a simple spec they ignored that came back to bite them?

Just dropped $350 on a new thermal camera for tracing shorts

My boss said it was a waste of money, but it found a tiny ground fault in a harness bundle in like 15 minutes. Saved me from pulling apart half the cockpit on a King Air. That thing paid for itself in one afternoon. Anyone got a better brand they swear by for this kind of work?

I used to fight with old Cannon plugs for hours before I learned the trick with the dental pick

I was working on a Beechcraft King Air's nav system last month, and I spent almost three hours trying to get a stubborn connector apart, which my boss saw and just shook his head. He walked over, took a dental pick from his kit, slid it into the release slot I'd missed, and it popped right open (I felt pretty silly). How many other 'simple' tricks did you all learn way later than you should have?

Was convinced those new fiber optic testers were overkill for our regional shop.

Had a stubborn intermittent fault on a Citation's databus that a standard meter missed for a week. The fiber unit pinpointed a micro-fracture in ten minutes. Anyone else made the switch and found it worth the initial cost?

Spent a whole shift chasing a phantom comms fault on a G280

It was a single pin in a D-sub connector that had backed out just enough to lose contact intermittently. Took me 8 hours of tracing and swapping boxes before I found it with a magnifier. Anyone have a better method for checking those connectors under the panel?

Pro tip: I bought a $200 thermal camera for my phone to chase down intermittent shorts.

It paid for itself in a week by finding a bad connector on a G1000 that was only failing at altitude. What's your go-to tool for the weird ones?

Heard a pilot on the radio say 'the box is happy' after a test flight

I was at the small airport in Bend grabbing a coffee last week. Over the radio, a pilot reported back to maintenance that 'the box is happy' after a full system check. It hit me that all our bench tests and wire checks are just to make sure that 'box' is happy for them up there. It's a simple way to think about the whole job. What's the best sign-off phrase you've heard from a crew after your work?

Rant: Everyone pushes for the new digital test sets, but my old Fluke 88V still gets the job done

Last week at the hangar in Tulsa, a guy was giving me grief for still using my Fluke 88V multimeter from 2010. He said I was 'behind the curve' because I wasn't using the new touchscreen diagnostic units. Thing is, three years ago on a night shift, that same 88V helped me find a 0.3 volt drop on a Cessna 172's comm power line that the fancy unit had missed because it was averaging the readings. Sometimes the simple tool you know inside out is better than the new box you're still learning. Anyone else stick with older gear because you trust it more?