c/aircraft-mechanics

That composite repair I was sure was snake oil saved my hide

I've been a mechanic for 12 years and I ALWAYS swore by metal patches for skin repairs. Then last month a supervisor on a C-130 job near Little Rock handed me a composite patch kit and told me to try it. I figured it would fail in a week but I followed the cure cycle exactly. It's been 6 weeks and that repair is holding up BETTER than the riveted patch on the other side. Have any of you actually switched to composites for structural fixes or am I still the odd one out?

Bethesda hangar 2019 - torque seal vs signed paperwork, which one holds up in court?

Warning: don't trust a torque wrench that's been sitting in a tool box for 6 months

I was doing a spark plug change on a Cessna 172 out in Bakersfield last month and my torque wrench clicked way too early at 25 foot pounds. Turns out the calibration drifted after sitting in the heat and I was under torquing everything by about 10 percent. Now I check it against a known standard before every job, even if it's just a quick maintenance task. Has anyone else had a torque wrench go bad from just sitting around?

PSA: Stop using WD-40 on aircraft hinges unless you like corrosion

Saw a new guy dousing a Cessna door hinge with the blue and yellow can last Friday. Told him that stuff collects dirt and dries into a gummy mess. Use LPS-1 or Tri-Flow instead. Anyone else have to play cleanup on a bird that got the wrong lube?

Overheard a lead mechanic say torque wrenches are just 'suggestion tools'

After that guy joked about it at the hangar in Phoenix, I checked 3 bolts on an engine cowling and found two were 15 ft-lbs under spec, so who else has seen lazy torque practices ruin a good inspection?

Heads up: I caught a loose fuel line at a regional airport in Boise last month

I was doing a routine preflight on a Cessna 172 at the Boise airfield last month and spotted something off. The fuel line clamp on the right wing was barely hand tight, I could spin it with my fingers. Turns out a temp mechanic had swapped a filter the day before and forgot to torque it down. This could have been a fire hazard on takeoff if it loosened further. I checked four other planes on the ramp and found two more clamps that were loose too. Anyone else seeing this kind of shortcut work from contract mechanics lately?

Tried using a cheap torque adapter from Harbor Freight on a critical bolt and it snapped clean off at 45 foot-pounds

I was torquing down a cylinder head on a Lycoming O-320 last Tuesday and the adapter broke, which could have ruined the whole engine if I hadn't caught it mid-crank; has anyone else had a bad experience with those budget torque tools on aircraft work?

Finally figured out why my torque wrench was always off

I had been using my torque wrench for three years and kept getting inconsistent readings on wing bolts. Turns out I was storing it with the spring compressed the whole time, and the calibration got all jacked up. Anyone else learn basic tool care way later than they should have?

Caught a cracked bell crank on a Cessna 152 during a 100-hour inspection yesterday

Found it hidden behind some grease buildup near the aileron cable linkage, and the crack was about an inch long heading toward the bolt hole. Has anyone else stumbled on something this spooky during routine checks?

Found a cracked bracket on a Cessna 172 after a rough landing in Kansas City

I was doing a post-flight walkaround last Tuesday and spotted a hairline crack on the engine mount bracket near the firewall. Ended up grounding the plane for three days while we ordered a replacement and did the paperwork. Has anyone else found hidden damage like that after a hard touchdown?

Just had a fuel nozzle fail on a 737 during pressure testing at DFW

I was running fuel nozzle pop tests on a CFM56-7B last Tuesday and number three nozzle just dribbled instead of atomizing at 90 PSI. The test bench said it passed but my eyes said different so I ran it again and got a bad pattern. Has anyone else caught a faulty nozzle that slipped through bench testing?

Switched from using a torque wrench on every bolt to just going by feel on interior panels

Used to torque every screw on cabin panels since I started 7 years ago at a regional airline in Dallas, but after getting burned by a digital torque wrench that was 30 ft-lbs off, now I just hand tighten and check with a wiggle test, has anyone else dropped the torque specs for interior work?

Hot take: Is it better to learn on older planes or should new mechanics jump straight into glass cockpits?

I had an argument with an old instructor back at the maintenance school in Detroit about this. He said you don't really understand a system until you've traced a wire on a 1970s 737 with a paper schematic. But the guy I work with now learned on a 787 and he can troubleshoot an LRU fault twice as fast as anyone else. I see value in both but I lean toward his side because most shops around here are moving to digital. What do you all think? Are we wasting time on old school methods?

Overheard a lead mechanic say something that made me rethink my tool cart setup

I was changing a fuel control unit on a 737 last Tuesday and this old timer walked by my cart. He pointed at my top drawer full of cheap Amazon wrenches and said 'son, every time you grab that, you're losing 10 minutes of your life'. I laughed it off at first but then I timed myself getting a proper snap-on wrench from the bottom drawer versus the cheap ones. He was right, the cheap ones slipped and I had to go back. Now I'm slowly swapping out my go-to tools and keeping the good stuff on top. Anyone else reorganize after a senior guy called you out?

The debate on replacing tires - new vs retread on a budget

I spent $1200 on a set of new retread tires for my Cessna 172 last spring at the shop near Bakersfield. They've held up fine for 8 months but I'm starting to see some weird wear on the edges that has me second guessing. On the other hand, a buddy spent double that on premium new tires and says they'll outlast mine by years. What's your take - are retreads a smart money move or a false economy waiting to bite you?

PSA: The debate on using torque wrenches vs feel for landing gear bolts

I used to always torque landing gear bolts by feel, especially on smaller Cessnas. Been doing it that way for 15 years and never had a failure. Then about 3 years ago I had a gear bolt shear on a 172 after a hard landing. Luckily nobody got hurt, but it scared me straight. Now I pull out the torque wrench every single time, even on quick jobs. But some of the old timers I work with still swear by feel and say I'm overthinking it. What's your take do you trust the tool or your hands more?

Spent 10 years chasing torque specs on sheet metal screws before a guy in Phoenix showed me what I was missing

Why does nobody talk about the tool control difference before and after foam cutouts?

I spent 5 years digging through a messy toolbox until I spent $80 on Kaizen foam 6 months ago and now I can find a 1/4 inch socket blindfolded, has anyone else noticed how much faster jobs go when you can see exactly what's missing before you leave the hangar?

PSA: Skip the digital torque wrenches for critical engine bolts

At my last inspection on a Cessna 172 at KDVT, I watched a guy use his fancy digital torque wrench on the cylinder hold-downs, and I had to bite my tongue. I still prefer my old beam-style Snap-on torque wrench that my mentor gave me 15 years ago. It never needs batteries, I can feel the needle hit the mark, and I know it's accurate because I calibrate it myself every 6 months. Who else still swears by the old analog stuff on critical fasteners?

I finally had to eat my words about that digital torque wrench my younger coworker recommended

I've been turning wrenches on planes for 28 years, started in the Air Force in the mid 90s. Always used a beam style torque wrench for everything. When this kid fresh out of A&P school kept pushing me to try his digital one, I told him no thanks, I don't need a battery telling me what I already feel in my hands. Last month I had a job on a 737 flap carriage bolt that calls for 250 inch-pounds with a very tight tolerance. I used my old beam wrench, set it, torqued it, felt good. He asked if he could double check it with his digital one just for fun. It read 232. That is out of spec by every standard. I was 18 pounds off and I never would have known. I borrowed his digital unit for all the other bolts on that job and ended up catching two more that were close but not quite there. Has anyone else made the switch from analog to digital and found it changed how they work? Or am I just old and stubborn?

Warning: that cheap borescope I bought off Amazon gave me a false reading on a cylinder wall

Picked up a $30 model last month and it showed scoring that wasn't there... turned out the lens was just dirty. Has anyone else had a cheap inspection tool lead them down a rabbit hole of unnecessary work?

Had a lead mechanic tell me torque wrenches are only for engines. He was dead wrong.

Dropped $300 on a borescope and it saved me a full engine teardown

Picked up a decent borescope off Amazon last spring for about 300 bucks. Thought it was a waste until I had a stubborn cylinder that kept failing compression checks but I couldn't find the leak anywhere. Stuck that camera down through the spark plug hole and spotted a hairline crack in the cylinder wall in under 5 minutes. Would have taken me a whole weekend to pull that jug off and inspect it the old way. That one find already paid for the tool 3 times over. Anyone else had a tool that felt like a gamble but turned out to be a lifesaver?

Just realized a 5 minute visual inspection saved me 4 hours of chasing a leak

I had a Citation that kept showing a slow pressure drop in the hydraulic system. Spent almost 3 hours pulling panels and testing lines with the mityvac. Gave up for the day. Came back the next morning, did a quick walk around and saw a tiny puddle under the left main gear wheel well. Turned out to be a loose return line fitting I could have spotted in 5 minutes. Anyone else find themselves overthinking and skipping the obvious stuff?

Watched a new guy torque a spark plug to 90 ft-lbs and I almost walked off the line

Last Tuesday we had this new A&P student shadowing on a 737 engine swap. He grabbed the torque wrench and cranked one of the spark plugs down like he was tightening lugnuts on a truck. I caught it at 90 ft-lbs before he moved to the next one. Spec is 30 ft-lbs max on those plugs and I've seen stripped threads ruin a cylinder head in under 2 seconds. This is basic stuff but people cut corners when they're nervous or in a hurry. How do you train new guys to slow down and read the manual before touching metal?