c/aircraft-mechanics

Old timer told me to skip a step on a 737 flap rig and I paid the price

Back when I was at a regional out of Detroit, a guy named Hank who had been doing this since the 70s told me I didn't need to torque the crank pulley bolts on a 737 flap actuator if I just gave them an extra quarter turn with a ratchet. I was green and figured he knew better than the manual. Three weeks later a flap failed to deploy on a landing and the MEL write up traced straight back to a loose bolt on that actuator. I spent six hours re-rigging the whole assembly and got written up by the DOM. Anyone else ever get bad advice from a senior mechanic that cost you time or worse?

Had a 5 minute talk with a retired FedEx mechanic that wrecked my head

He told me he never uses safety wire pliers because his hands are faster after 40 years, and now I'm wondering if I've been slowing myself down with tools I don't actually need.

The zip tie trick that saved me 2 hours on a 737 bleed air leak

I was chasing a bleed air leak on a 737 at the gate in Phoenix last Friday. After my third round of clamping and spraying soapy water with zero luck, I tried that old trick where you wrap a piece of string around the suspect fitting and pull it tight. Found the leak in under 10 minutes where the fitting was just barely loose. Has anyone else used the string method for finding tiny leaks that won't bubble up?

Visited the Pima Air Museum last weekend and noticed something odd about the B-52

I was out at the Pima Air Museum near Tucson this past Saturday checking out their exhibits. They have a B-52 Stratofortress sitting out on the tarmac and I got to walk right up under the wing. What caught my eye was how the rivet patterns looked different on the wing panels compared to newer aircraft I work on. The panels had these big overlapping seams with rows of rivets spaced about every inch, while the tail section used flush rivets that were almost invisible. I asked one of the volunteer guides about it and he said the wing panels were original 1950s construction before they switched to smoother skins. Made me appreciate how far we've come with panel alignment and corrosion prevention. Has anyone else noticed this kind of thing on older airframes at museums?

Unpopular opinion: sometimes you gotta walk away from a grounded plane and come back fresh

Last Tuesday I was chasing a pressurization fault on a 737 that had me swapping outflow valves and chasing checklists for 6 hours straight. I hit a wall and couldn't even read the schematic right. My lead told me to go grab a coffee and cool off, so I took 20 minutes walked around the ramp. Came back and spotted a missing ground strap on the cargo door seal that I swore I checked twice. Has anyone else had a head-scratcher where stepping away actually fixed the troubleshooting faster than pounding on it?

Rant: Almost torqued a prop flange wrong after watching a YouTube video

I was replacing a prop seal on a Lycoming O-320 last Tuesday up in Green Bay, and I caught myself about to use a beam torque wrench I saw some guy recommend online. He claimed it was more accurate for low range stuff, but I got to thinking about it while I was holding the thing. That beam wrench needs you to look straight on at the needle, but in that tight cowling space I was kneeling weird and couldn't get my eye line right. I would have been off by probably 10 foot-pounds easy if I didn't stop and swap for my clicker type. Now I just stick with the clicker for anything in the airframe, no matter what some random dude says on his channel. Has anyone else almost messed up a critical torque because you trusted a video over your own tool?

Had a passenger ask me if I could 'just tighten the bolts' while I was doing a preflight in Atlanta

I was doing a walkaround on a CRJ-900 at Hartsfield last spring and this guy in a suit walks up from the gate area. He watches me for a minute then asks if I could tighten the bolts on the landing gear because they looked loose. I told him those are engineered to have some play and he goes 'well my truck's suspension doesn't rattle like that.' I had to stop and explain that a 80,000 pound plane hitting the runway at 150 mph needs a little wiggle room. He just shook his head and walked off saying he'd complain to the airline. Still cracks me up thinking about that guy comparing aircraft landing gear to his F-150. Any of yall ever deal with passengers who think they know more than the mechanics?

PSA: Stop ignoring the AD notes on older Gulfstreams

I just wrapped a GIV-SP inspection last week in Savannah and found 3 corrosion spots that matched an AD from 2019 that nobody at our shop had flagged. It took 22 extra man-hours to fix, all because someone didn't update the binder. Has anyone else dealt with outdated AD compliance systems causing this kind of headache?

Heated debate: Should we use lithium grease on landing gear or stick to the old stuff?

I was down at the hangar at KBWI last Thursday watching a crew do a landing gear overhaul, and they had a big argument going about grease. One old timer swore by the traditional Aeroshell grease, says it's been working for 30 years and he's never seen a failure. The other guy, younger guy, was pushing a new lithium-based grease because it handles heat better and doesn't drip as much in summer. I've been doing this for about 6 years now, mostly line maintenance, and I've only ever used what the manual says. But seeing them go back and forth got me thinking, is there really a better option out there or is it all just manufacturer hype? The older grease leaves a mess on the struts sometimes, but the lithium stuff costs twice as much. Anyone here switched from the standard to something newer and seen real results, or should I just stick with what's in the book?

PSA: using a rubber mallet instead of a metal one saved me hours on panel work

Was fighting with a stubborn access panel on a 737 last month, kept denting the edges with my standard hammer. Lead mechanic walked by and just handed me this old rubber mallet he had, said "try this." One tap and it popped right in, no damage. Been using one ever since for anything that doesn't need real force. Why didnt anyone tell me this sooner? Has anyone else got a simple tool swap that made a big difference?

Heard an inspector say half the torque values on the line were off by 15% last week

I was in the break room at LAX when I overheard an inspector telling a lead that someone checked 20 fasteners on a 737 and 10 were under torqued. Nobody's owning up to it yet but the lead just said 'we'll handle it quietly.' Has anyone else seen this kind of thing get swept under the rug at their station?

Split between letting the new guy touch the APU bleed valve or keeping him on paperwork only

My lead back in Denver let a rookie try to isolate a bleed leak on a 737 and after 2 hours of him fighting it we found out the whole issue was just a loose clamp, but man, did that teach me anything about when to step in and when to let them learn the hard way, so what do you all think, do you give green mechanics the reins or stick to babysitting?

Serious question, found a chart that says 70% of fastener failures come from overtightening, not undertightening

I was updating my torque wrench calibration log last Tuesday and stumbled across a study from the FAA that says something like 70% of fastener failures on aircraft are from overtightening. I always thought undertorquing was the bigger risk, but this chart showed it's way more common to strip threads or stress the metal by cranking too hard. I double checked my own work and realized I've been leaning into that "tight is right" habit more than I should. Has anyone else seen this data and changed how they torque things up on the line?

Blew a hydraulic line on a 737 yesterday and it was my own dumb fault

Was doing a routine brake change on a 737-800 at the hangar in Phoenix around 2pm. I got in a hurry and forgot to properly relieve the pressure in the system before cracking the line. Got sprayed with skydrol all down my arm (thankfully I had goggles on) and made a huge mess on the floor. Took me an extra hour to clean up and re-bleed the whole system. Anyone else ever had a moment where rushing cost you way more time than just doing it slow the first time?

Finally got my IA after three years of night classes

Took my oral and practical last week at the FSDO in Cleveland, and the examiner asked me to walk through a 100-hour inspection on a Cessna 172. I was nervous, but having my own tool roll from the shop helped me focus. Anyone else get their IA recently and have tips for the first year?

Hot take: That $90 'universal' torque wrench adapter from the trade show is a paperweight.

It slipped on a 3/8 drive and almost rounded a critical bolt head on a Cessna flap actuator. Anyone got a brand they actually trust for oddball fittings?

Had a choice between a $1200 torque wrench with a digital readout or a $350 analog one for a Cessna 172's engine mount job. Went analog and it's been solid for 3 years now.

Seeing a lot of guys skip the final torque check on CRJ-700 nose gear uplocks

I've watched three different mechanics at my hangar in Phoenix just hit the bolts with an impact and call it good. The manual is clear, you need a final torque pass with a calibrated wrench to 150 inch-pounds after the initial run-up. It matters because that uplock failing on taxi is a serious write-up, and I've seen it happen twice this year from hangars that don't follow the book. Anyone else's shop having to re-train on this simple step?

Vent: I think the new composite patch kits are a step back from the old aluminum ones, even though everyone at my hangar loves them.

I mean, maybe it's just me but I had a 3-inch delamination on a rudder skin last week and the prep time for the composite kit was double what it would've been for a simple doubler, so has anyone else found a faster method that actually holds?

My old foreman told me to always torque a prop bolt twice, and I just found out why

Back at my first job in Tulsa, my foreman insisted on torquing the prop bolts on a Cessna 172, waiting ten minutes, and hitting them again. I thought it was overkill until I skipped it on a rush job. Next inspection showed two bolts had backed out a quarter turn. He said the aluminum hub settles under initial load. Now I hear some shops call that second pass a waste of time. What's your take on the double-torque method for props?

Got called out on my wire routing during an inspection, and it stuck with me

I was finishing up an avionics install on a Cessna 172, routing a bundle behind the panel. I had it neat and secure, or so I thought. The lead inspector, a guy named Carl who's been at our field for twenty years, took one look and said, 'You're giving that harness a free ride to chafe city against that firewall bracket.' He was right. I'd focused on zip tie spacing but missed how the whole run would shift and settle in flight against a sharp edge. I redid the whole thing, adding two more adel clamps to create a positive standoff. It took an extra hour, but now I mentally trace the full path of any wire, looking for potential contact points over a thousand hours, not just how it sits on the bench. Has anyone else had a simple piece of feedback that completely changed a routine step for you?

Had a pilot swear by this old-school torque wrench trick for years

Honestly, I thought it was just hangar talk until I saw a guy at the MRO in Phoenix use a Sharpie on the drive square to spot-check for movement under load. Ngl, it actually works for a quick visual on those awkward firewall bracket bolts. Anyone have other simple tricks like that for verifying torque in tight spots?

I used to think a torque wrench was just for the big bolts until a job in Boise.

I was doing a quick turn on a King Air in Idaho, and the cowling started rattling like crazy after takeoff because I'd just hand-tightened the small fasteners. We had to turn back, and I found three of them had worked loose, which was a real eye-opener. What's the smallest fastener you guys actually break out the torque wrench for?

Heard a line chief say 'a clean floor is a safe floor' and I used to think that was just busywork. Saw a guy slip on a tiny oil spot near a 737's main gear last week. Changed my whole view.

Question about the torque on a 737's engine mount bolts

I was reading an old maintenance manual from the 90s for a 737-300 and saw the torque spec for the engine mount bolts. It said 450 foot-pounds, which just seemed huge to me. I had to double-check it with a senior mechanic who confirmed it. He said the shear loads during a hard landing or turbulence are way bigger than you'd think. Has anyone else been surprised by a torque value they found in an old manual?