c/avionics-technicians

5

karenm49•10h ago

Tried calibrating an altimeter with a known bad test set just to see what would happen

Pulled the ancient Barfield DPS-100 off the shelf last Tuesday knowing it was out of tolerance and ran a 737 pitot-static check anyway. The altimeter read 120 feet low at sea level, which taught me to never skip the calibration sticker even if you're in a hurry. Anyone else ever get bit by a test set that drifted without you noticing?

16

the_nina•3d ago

Overheard a junior tech say an open bond check is optional

I was sitting in the break room last week and heard a younger guy telling his buddy it's fine to skip bond checks if the panel looks clean. Took me right back to a Delta flight in Atlanta where a loose bond wire caused a static discharge that killed a whole nav display. How do we make sure new guys understand the stakes without sounding like grumpy old heads?

9

maxm63•4d ago

A senior tech told me I was reading wiring diagrams all wrong, and he was right

Been doing avionics for about 7 years now, and I always thought I was pretty good at tracing circuits. Then this old-timer, Frank, watched me work on a 737NG in Phoenix last month and just shook his head. He said I was reading the diagram like a book left to right when I should be following the power flow from the source to the load and ignoring everything else on the page. I felt like an idiot but I tried it on a tricky hydraulic pump relay issue the next day, and I found the short in about 10 minutes instead of an hour. Now I tape a piece of paper over the parts of the schematic I'm not working on so my eyes don't wander. Has anyone else had a basic habit like that totally changed by a grumpy senior tech?

24

eric_murphy36•24d ago

Got hit with a weird voltage drop on a King KX 155 install last Tuesday

I was wiring up a replacement nav/com in a Cessna 172 at the hangar near BFI, and the unit kept cycling off after 10 seconds. Turned out the ground strap on the engine mount was corroded, causing a bad ground loop that backfed into the avionics bus. Has anyone else seen a simple ground strap cause that kind of intermittent failure?

23

maxm63•25d ago

Pro tip: It took me 3 years to stop using a multimeter on every single wire

I used to test every wire I touched with my Fluke before doing anything else, even if I just pulled it out of a harness an hour ago. My old lead at the repair station in Phoenix drilled it into me that you never assume a wire is dead or clean. Last month on a King Air pitot-static check, I spent 45 minutes chasing a bad connection that turned out to be a loose pin I already tested twice. That changed how I work because now I focus more on the physical connection first before grabbing my meter. I still test, but I look for bent pins or corrosion with my eyes before I ever clip a lead on. Has anyone else had to unlearn a habit that slowed you down more than it helped?

25

lisa_grant•25d ago

Spent 5 hours tracking down a faulty connector pin on a 737NG that was intermittently dropping the right VOR signal.

It turned out to be a single pin that was pushed back maybe 1mm in the connector shell, and I only found it because I got frustrated and started wiggling each wire one by one with a pick - has anyone else wasted half a shift on a stupid pin issue like that?

11

claire_fisher41•29d ago

Hit 200 hours on my bench power supply and it finally clicked

I was working on a old King Radio nav unit from a 1970s Cessna and kept getting weird voltage readings. After about 150 hours of bench time I realized I was using a cheap multimeter that drifted like crazy. Swapped to a Fluke 87V and suddenly all those problems made sense. Has anyone else had a tool swap fix a bunch of weird issues at once?

33

thomas_roberts•29d ago

TIL spending $60 on a coax stripper either saves hours or costs you a headache

I dropped $60 on a good coax stripper for a job last month, and it cut my prep time in half, but my buddy swears by the $15 cheap ones that work fine until they don't. Anyone else deal with this split, or is it all about how many connectors you're cranking out?

14

claireg81•29d ago

Overheard a lead tech say we should skip the pin drag test on a CRJ900 harness

Was doing a harness checkout last shift and one of the senior guys told the new kid not to bother with a pin drag test because "the pins are always good." I kept my mouth shut but that just feels wrong to me. I've seen dirty or worn pins cause intermittent faults on the EMB145 before. Am I being too cautious or should we always do the drag test even on newer ships?

6

james661•1mo ago

Pop quiz from my lead avionics tech stumped me on wire gauge vs current limits

I followed the IPC-620 chart to the letter for a 24 AWG wire on a 7-amp load last week and the breaker kept tripping, but the old-timer says that gauge can handle it with shorter runs, so who's actually right about derating for bundle density?

5

wesleypatel•1mo ago

Senior tech told me to stop using my mulitimeter on the 'auto' setting

I've been doing avionics for about 3 years and always just left my Fluke on auto-range for everything. Last week a 20 year veteran saw me testing a connector on a 737 and said 'you're gonna chase ghosts like that.' He showed me how setting the range manually cuts out all the false readings from induced noise. Anyone else have a simple habit change that made a big difference in troubleshooting?

27

campbell.logan•1mo ago

Stop twisting wire pairs before you crimp them - it messes up signal integrity

I was troubleshooting a 767's weather radar antenna feed last Tuesday and found the real issue was a guy from the night shift who twisted the RG400 braid into a tight pigtail before soldering the connector. It changed the impedance just enough that the radar showed false returns and flagged a 3 degree error. I've seen this on at least 4 installs this year where people think they're being neat but they're actually creating a mismatch. Has anyone else run into this or am I the only one who bothers checking with a TDR after a connector gets replaced?

6

sandralee•1mo ago

The time a senior guy told me to always zero my torque wrench after every use

I had this old timer named Doug at my first shop in Denver who swore up and down you had to back the torque wrench down to zero after every single job. He said leaving it set at 20 inch pounds or whatever would mess up the spring over time. I listened to him for like two years straight, never had an issue. Then I swapped to a new hangar and the lead tech there laughed at me for doing it. He showed me the manual for the same brand torque wrench and it said storing it at the lowest setting is fine, just not maxed out. I felt kind of dumb but also Doug was so sure about it. Anyone else get told some old school rule that turned out to be overkill or just plain wrong?

14

lewis.charlie•1mo ago

Dropped $1200 on a used oscilloscope off eBay, got burned bad

Found what looked like a decent deal on a Tektronix TDS 210. Seller said it worked fine, just some cosmetic wear. Got it in the mail and it won't hold a calibration for more than 20 minutes. Traces drift all over the place. Been troubleshooting it for a week now and I think the power supply board is toast. Has anyone had luck fixing these old scopes or am I better off just eating the loss?

29

cameron763•1mo ago

Wasted $60 on a cheap coax crimper, wrecked 8 connectors before I gave up

Last week I bought a no-name crimper off Amazon for my GA plane's antenna cable. First connector looked fine. Second one the center pin slipped right out after I tugged it. By connector 4 I had mangled three more. My A&P buddy handed me his Daniels crimper and it worked first try. That cheap tool cost me $60 plus $40 in wasted connectors. Anyone else have a tool fail like this mid-job?

9

price.jake•1mo ago

Hot take: PCB inspection scopes are overrated for most bench work

Spent 8 years using a $600 inspection scope for every connector pin check, then switched to a cheap 10x loupe from a tool truck back in February. On a 747 harness repair last month I caught a broken pin in about 10 seconds with the loupe that the scope missed twice. Has anyone else ditched the expensive gear for simpler stuff?

5

sage52•1mo ago

I finally caught why my ground checks kept failing on the same panel

So I've been working on a King Air 350 out of a hangar in Boise for the last two weeks, chasing a weird intermittent fault on the weather radar display. Kept getting a ground check failure every third or fourth time. Replaced the waveguide, swapped the antenna drive, even pulled the display unit and bench tested it. Everything passed. Then last Friday I noticed the copilot's side window seal was letting a tiny drip of water in right above the radar controller. Must have been moisture causing a short on the connector pins. Nobody else thought to look up there because the radar antenna is in the nose. Now I always run a moisture check on any panel near a window seal before swapping parts. Anyone else found corrosion in weird places from something dumb like a leaky seal?

18

the_hugo•1mo ago

Three hour fight with a stubborn ground loop in a King Air

Spent all afternoon yesterday tracing a ground loop that turned out to be one corroded connector pin on the audio panel. Should have been a 20 minute swap but I chased it through half the avionics bay first. Has anyone else wasted a shift on something that tiny?

8

ninab95•1mo ago

Vent: The constant misuse of torque wrenches on LRU connectors

I keep seeing guys at my hangar in Tampa just crank down on D-sub connectors like they're tightening a lug nut. The spec sheet for a standard 9-pin connector is 15 inch-pounds, not 'good and tight'. I had to re-pin three of them last month because someone crushed the backshells. Does anyone actually use a torque screwdriver for avionics anymore, or am I the only one?

10

ruby_lane•1mo ago

Found a trick for tracing intermittent ground faults in the panel

I spent 3 hours last week chasing a ground fault on a King KX 155 nav radio that kept popping up and disappearing... driving me nuts. Finally tried hooking up a 12V test light in series with the ground lead instead of just using my multimeter. The light flickered dimly when I wiggled the harness near the backshell connector. Turns out a single strand of shielding was barely touching the pin inside the connector. Fixed it in 10 minutes after that. Has anyone else used a test light this way or do you guys stick to megger testing for intermittent stuff?

30

parkerkim•1mo ago

Warning: The new Fluke 87V versus the older 87V Max on a recent King Air job

I had to chase down a phantom voltage drop on a King Air 350 last week. Grabbed my shop's new 87V, got a clean reading. For a sanity check, I used my personal 87V Max from 2018. The Max showed a 0.3V fluctuation the new meter completely missed, which was the root cause. That older True RMS just seems to pick up the noise better on these 28V DC systems. Anyone else found a specific meter that catches gremlins the newer ones don't?

22

patricia905•1mo ago

Warning: The new FAA repair station in Phoenix has a policy I can't get behind

I was there yesterday for a certification check and saw they have a rule that all avionics bench tests must be done with the unit fully installed in a mock-up airframe section. They say it's for 'real world conditions', but it adds at least 2 hours to every single bench check. I mean, idk, maybe it's just me, but for a known-good unit swap or a basic LRU check, that's overkill and kills shop efficiency. It feels like a solution looking for a problem when a solid bench test on proper gear has worked fine for decades. Has anyone else run into this kind of rule at a newer facility?

12

uma306•1mo ago

A night shift in Anchorage made me stop trusting the book for every fault code

We had a 737 with a flickering nav light and the manual said to replace the whole unit, but I found a bad ground in the wing root after tracing the wire for two hours. Now I think we jump to the book fix too fast instead of doing the basic checks first. How many of you still start with the wiring diagram before you even open the book?

24

brian_jackson•1mo ago

Overheard a pilot at the FBO say our panel looked 'factory fresh' after a recent upgrade

It was just a quick comment while he was doing his walk-around, but it felt good knowing the work was noticed. Anyone else get a random bit of praise that made the whole job feel worth it for a minute?

22

derek_dixon78•1mo ago

Hot take: I keep seeing guys skip the torque wrench on coax connectors

A supervisor at my old hangar in Tampa showed me a stripped-out BNC that cost a $2k radio replacement, all from over-tightening. What's your go-to method for making sure those connections are just right?