c/aircraft-mechanics

Blew $300 on a cheap borescope that couldn't see jack inside a cylinder

I bought a no-name borescope off Amazon last spring to inspect some cylinder walls on a Lycoming. The picture was so blurry I couldn't tell carbon from a crack. Ended up having to borrow a buddy's Snap-on unit, which worked perfectly first try. Don't waste your cash on those cheap ones - just rent a good scope from the tool truck if you need it once.

Fixed a stubborn APU bleed valve with a brass punch and a mallet

Honestly, I was ready to pull the whole valve assembly on a CRJ at FNT last night after three hours of fighting it. Ngl, a couple light taps broke it loose and saved me a ton of disassembly time. Has anyone else had luck with percussive maintenance on bleed air stuff?

Took me 5 years to figure out I was cleaning spark plugs wrong

I always used a wire brush on spark plugs until a guy from the hangar next door saw me doing it last month. He said I was probably scratching the ceramic and making them fail sooner. He showed me how to use a sand blaster on low pressure instead. Has anyone else been doing this the hard way too?

Tried a crescent wrench on fuel line fittings for years until a old timer showed me the crows foot trick

I was stuck on a Cessna 210 fuel strainer drain valve yesterday, and that 5/8 line nut would NOT budge. I've been using a crescent wrench like a dummy for 3 years on these things. This old mechanic walks over, hands me a crows foot on a wobble extension, and it came off in 2 seconds flat. No more rounding off fittings for me. Has anyone else learned a basic tool trick way later than they should have?

Found a trick for stuck bolts on a 747 flap actuator

Been working a 747 flap actuator job over in hangar 3 and hit a bolt that just would not budge. Soaked it in PB Blaster for 20 minutes, nothing. Tried heat, still nothing. Then one of the older guys, Mike, told me to tap the bolt head with a hammer first before any wrenching. I thought he was messing with me, but I gave it 3 taps and the thing came loose like butter. Anyone else use this trick or got a better way on those big airliner fasteners?

Co-worker called me out for not torquing spark plugs on a Cessna 172 and I was dead wrong

Snapped a torque wrench on a 737 flap actuator Tuesday

I was in the hangar at KMDW working on a flap actuator for a 737-800 and my old Snap-On torque wrench just gave out with a loud crack at 120 inch-pounds. Turned out the internal mechanism had been slipping for weeks without me noticing. Had to borrow a backup from the lead mechanic and re-torque every bolt from scratch. Anyone else ever have a tool fail mid-job like that?

Stumbled on a fact about turbine blade counts that surprised me

Was reading through an old Pratt & Whitney manual I found at a garage sale, and it said some of their early JT8D engines had like 29 blades per stage on the low-pressure turbine. I always assumed they kept it consistent across models. Has anyone else run across weird specs in old manuals that made you double-check?

My digital torque wrench lied to me on a critical job

I use a Snap-on digital torque wrench for most of my work. Last week I was torquing cylinder head bolts on a Continental O-470. The wrench clicked at the right number, felt right, so I moved on. Engine ran rough on the test stand, so I pulled the head back off. Found five bolts that were way under spec, like 40 foot pounds when they should have been 60. The wrench had a dead battery that gave false readings before it finally quit. I checked the calibration sticker and it was 14 months overdue. Now I keep a spare battery in my box and I check calibration dates on everything every 6 months. Anyone else ever get burned by a tool you thought was fine?

Bought a $300 borescope and it paid for itself in one inspection

I always thought they were overkill until I found corrosion inside a wing spar on a Cessna 172 that I'd have missed with a mirror and flashlight. Has anyone else had a cheap tool actually save them money on the first job?

Just hit 10,000 flight hours on the same torque wrench

I was doing the annual on a Cessna 172 last Friday and realized I've been using the same Snap-on torque wrench for almost 15 years now. It clicked over to 10,000 hours on the job log I keep tucked in the case. That thing has never needed a calibration adjustment more than 2 percent off. Has anyone else had a tool last that long without failing?

Mentor at my hangar said 'torque it to feels tight' after I asked about a spec

I was working on a Cessna 172 flap track last Tuesday and couldn't find the torque value in the manual for one of the bolts. Old mechanic named Dave walks over, looks at my wrench, and says 'just torque it to feels tight, that's what we did before they printed all those numbers.' I thought he was joking but he was dead serious. He said he's been doing it for 30 years without issues. I ended up finding the spec online anyway and set it to 65 in-lb. Has anyone else ran into this kind of old school thinking on the floor? How do you handle it without starting a fight?

Tried tracking down an air leak under the dash on a King Air and lost 6 hours to a loose hose clamp

Last month I was chasing a cabin pressure leak that kept showing up in the logbook, and I pulled half the interior apart before I found a clamp that was just barely loose behind the right sidewall. Took me a full shift to locate it because the leak only showed at altitude and I couldn't replicate it on the ground. Has anyone else spent way too long hunting a simple leak that turned out to be something dumb like a clamp or a seal?

Guy at O'Hare taught me a trick with lockwire that I still use

Met this old Delta mechanic in the break room at ORD during a layover, and he showed me how to double-twist lockwire with my eyes closed. Has anyone else had a random person drop some unexpected knowledge like that?

Was dead set against those ultrasonic cleaners for years, then my buddy ran a greasy fuel servo through his and I ate my words.

I watched 40 years of caked-on varnish dissolve in 15 minutes and now I'm trying to figure out which model fits under my bench without breaking the bank... anyone else finally cave on a tool they swore they'd never need?

Bit the bullet and switched from pneumatic to cordless torque wrenches last spring

I was on the fence for months about dropping the cash on a Snap-on cordless 1/2 inch drive. Finally did it after hanging off a 737 cowling in June trying to reach a stubborn fastener. Saved me about 20 minutes per job and my shoulder stopped hurting after a week. Anyone else made the switch or still hanging onto air tools?

Can we talk about people who use crescent wrenches on safety wire?

I keep seeing guys at the hangar grabbing an adjustable wrench to twist safety wire instead of just using the proper pliers... it leaves those little gouges and then the wire snaps at 200 hours. Why not just grab the right tool from the box, it's like 10 seconds more.

Stripped 20 bolts before someone told me I was using the wrong ratchet direction

I've been turning ratchets the same way for 5 years on the flight line at a regional carrier in Ohio. Last Tuesday a senior mechanic watched me struggle with a stubborn bolt on a CRJ flap track and just stared at me. He finally says "you know you're loosening it by turning it the wrong way right?" I thought I was tightening but I guess I had been working against myself this whole time. What simple thing took you way too long to figure out?

Snapped a torque wrench on a Cessna 172 cylinder bolt

I was torquing down a cylinder base nut on a 172 out in Phoenix last summer, and the wrench just snapped clean at 150 in-lbs. Had to borrow a snap-off from the A&P next hangar over, cost me an extra hour and a bruised ego. Anyone else had a tool fail on a critical fastener?

That one passenger who watched me torque bolts for 10 minutes straight

Had a guy stand right behind me at the gate in Denver last month, just staring as I torqued down a cowling panel. He asked if I was sure it was tight enough, like I hadn't done this a thousand times before. Has anyone else had a passenger just hover and question your work like that?

Kept finding loose screws on engine cowlings until I changed my routine

I work at a small regional airport in Nashville, and for the last few months I kept pulling cowlings that had at least one screw barely finger tight. Turns out a couple of the guys on my shift were starting the fasteners from one side and going in order around the panel. That leaves uneven pressure and the first ones get loose. I started doing a cross pattern like you do with lug nuts on a car, tightening opposite screws first. After 3 weeks of that, not a single loose fastener on my checks. Has anyone else run into this with their crew and found a better way to teach it?

Took an old timer's advice on safety wire direction and it saved my skin

I had this crusty old mechanic named Jerry watch me safety-wire a prop governor last spring at our hangar in Tulsa. He told me I was twisting the wire the wrong way and said I should always spin it so the loops tighten clockwise instead of counterclockwise. I thought he was just being picky since I'd been doing it my way for two years with no issues. But last month during a run-up, a loose bolt on a Cessna 210 vibrated free and that safety wire held because the twists were pulling tight instead of loosening. Jerry just nodded at me from across the hangar and didn't say a word. Anyone else have a mechanic call them out on something small that actually mattered later?

Old timer told me to stop using Teflon tape on hydraulic fittings

Kevin, a guy who's been doing this since the 80s at the regional base in Memphis, kept yelling at me every time he saw me wrap tape on a B-nut. I ignored him for like 6 months because that's how I was taught at school. Then last week I had a 737 skid valve fitting start weeping on the ramp after a pressure check. Kevin just walked over, cleaned it off, and the dry flare held perfectly. He showed me how a tiny piece of tape can get cut off and contaminate the whole system. Now I only use tape on pipe threads like NPT fittings. Anyone else have an old timer call you out on something you thought was standard?

Tried skipping the torque wrench on bleed screws - worked fine for me

Honestly, everyone says you absolutely need a torque wrench for brake bleed screws on light aircraft, but I tried doing it by hand on a Cessna 172 last month. I just used a 1/4 inch drive ratchet and went slow, snug then just a tiny bit more. No leaks, no stripped threads, and the brakes felt perfect on the test run. I get the whole torque spec thing, but for these small screws, it seems overkill if you've got a good feel for it. Any other mechanics out there skip the torque wrench on low-torque stuff like this?

Finally got that 737's persistent bleed air leak sorted after three days of chasing ghosts.

Turns out the O-ring on the precooler control valve was just slightly out of spec, something you'd miss unless you pulled the whole assembly in Dallas. We replaced it with a fresh one from the kit and the pressure held perfectly. Ever have a gremlin that was just a simple part wearing out a little early?