c/aircraft-mechanics

My old way of checking for fuel leaks was a mess, literally.

I used to just wipe down a fitting and watch for a wet spot, which wasted time and left streaks. After a supervisor at the Phoenix MRO saw me doing that three times on a 737, he handed me a bottle of leak detection fluid and said 'try this once.' Now I use that fluid every single time because it bubbles instantly at the source. Anyone have a favorite brand or a different method that's faster?

Remember when we used to torque bolts by feel? My old crew chief would just say 'good enough'.

Back in the early 2000s at a regional shop in Tampa, we had a lot of old timers who would just run a bolt down until it 'felt' right. I did it too, honestly. The change for me came about five years ago when I got a job at a major MRO. The first thing they handed me was a calibrated torque wrench and a manual with SPECIFIC inch-pound values for every fastener on a 737 flap track. It felt slow at first, but after seeing a stripped bolt on a wheel assembly from over-torquing, it clicked. Now I won't touch anything without the manual open and the right tool. The paperwork is a pain, but it's the right way. Anyone else have a shop that made that switch and how did you get the old guard on board?

Back in '08 we'd hand-torque every single bolt on a flap track... now the shop just wants us to use the electric wrench and trust the calibration.

Question about a hydraulic line leak on a King Air 200 we had in the shop

We had a persistent seep on a right main gear line for months. After three attempts with standard seals, our lead, Mike, suggested switching to a specific high-temp fluorocarbon O-ring from Parker, part number 2-009. The difference was immediate; the line has been bone dry for over 60 flight hours now. Has anyone else had a similar fix with a different seal material on older Beechcraft?

Overheard a pilot call a torque wrench a 'clicky thing'

Was doing a walkaround on a Cessna 172 last Tuesday. Pilot in the next bay asked his buddy to hand him the 'clicky thing for the bolts'. Took me a second. He meant a torque wrench. Made me think about the jargon gap between the flight line and the hangar. Ever hear any other funny names for tools from the cockpit crew?

Just hit 1,000 torque checks on a single engine model

It's the CFM56 on a 737, and I swear I could do it in my sleep now (my hand just knows the click). Anyone else get weirdly good at one super specific task?

Visited the Museum of Flight in Seattle and saw a 1930s engine manual that basically said 'just hit it with a hammer'.

Overheard a guy at the hangar say 'a clean workspace is a sign of a slow mechanic' and I couldn't disagree more.

My most efficient repair on a Cessna 172's landing gear last month came from a spotless bench where I found the sheared bolt in under 10 minutes because nothing else was in the way.

Spent $300 on a fancy torque wrench that turned into a joke

I bought this digital torque wrench for a specific job on a Cessna 172's landing gear, thinking it would make things foolproof. The battery died right in the middle of the final bolt, and the manual said it needed a special charger I didn't have. What's your go-to backup when a new tool lets you down on the line?

Update: I thought using a heat gun on a stripped bolt was a bad idea until I saw a guy in Anchorage do it with a coffee can.

PSA: I used to think those cheap harbor freight inspection mirrors were junk, but one saved me a whole day of work.

For years I refused to use anything but the expensive, name brand tools. I was working on a Cessna 172 last month, trying to see behind a baffle in the engine compartment for a potential oil leak. My good mirror was in my other box at the hangar. A guy lent me his cheap, flimsy harbor freight mirror with the little LED light. I figured it would break or give a bad view. I got it in there, and the light was actually bright enough to clearly show a tiny crack in a weld on an oil line fitting. Without that little light, I would have had to pull the whole baffle, which is a 3 hour job minimum. I bought a pack of three for $12 the next day. They are not my main tool, but having a few disposable ones in the box for tight spots is now a no brainer. Has anyone else found a cheap tool that actually works well for a specific job?

Watching a new guy torque a Cessna 172's nose gear bolt made me realize a common mistake

He was pulling the wrench handle instead of pushing it, which can throw off the reading by up to 15%. I learned that from an old A&P instructor in Tampa. Do you have any other tips for accurate torque wrench use on small aircraft?

Warning: Found a cracked torque link on a Cessna 172's nose gear last week

It was during a 100-hour check at our shop in Boise. The crack was small, about an inch long, hidden under some old grease. I replaced the whole link and checked the rest of the gear assembly. Has anyone else seen this on a 172 with around 800 hours on it?

Just spent three days chasing a phantom hydraulic leak on a King Air

We had a small drip from the right main gear area, maybe a drop every ten minutes. I replaced two O-rings and a fitting, but it kept coming back. Turns out the leak was actually from a tiny crack in a hard line up near the actuator, and the fluid was running down and dripping at the lowest point. The whole job, from first seeing it to final sign-off, took about 28 hours of actual work over three days. I felt pretty silly for not checking the full line path first. Has anyone else had a leak that was way higher up than where it showed itself?

Serious question, has anyone bought that new torque wrench adapter from that online tool place?

I dropped $80 on one last month thinking it would save me time on the CRJ-200 gear door actuators. The thing sheared on the third bolt, leaving me with a stripped fastener and a two hour delay. What's a better brand for that kind of precision work?

Got called out for my torque wrench technique by a lead at the hangar in Phoenix. I thought I was being careful.

Pro tip: I chose to replace a whole Pratt & Whitney fuel pump instead of just the seals on a King Air.

The shop lead said it was overkill, but the plane had a history of seal failures and I didn't want it coming back in two weeks. It cost the owner about $4,200 more, but we haven't seen that plane for a fuel issue since. Do you ever go for the bigger fix even when the book says the small one should work?

Shoutout to the old-timer at the Oshkosh airshow who showed me his trick for freeing a seized AN bolt with a candle.

He said, 'Kid, heat's fine, but a little wax wicks right into the threads and breaks the corrosion without the risk of galling you get with a torch,' and it saved me a huge headache on a Cessna 172's flap hinge last week.

Showerthought: The new guys always skip the torque stripe on the 737 main gear bolts

Honestly, I see it all the time at our hangar in Kansas City. They think if the wrench clicks, they're done, but that stripe is your visual backup. I caught a set last month with three bolts already backing out before the plane even moved. How do you guys get them to take the extra five seconds?

Been torquing those 3/8 bolts on the Cessna 172 cowl pins wrong for years

I was helping a new guy yesterday and he asked why I was using the click wrench on the nut side instead of the bolt head. I checked the manual again and sure enough, I had the sequence backwards this whole time. How many other simple things have I been doing on autopilot without really looking?

Question about a stripped bolt on a Cessna 172 cowling hinge

I was doing a pre-flight check on a Cessna 172 last Tuesday morning and went to open the cowling. The forward hinge bolt on the pilot's side just spun in place. The head was completely rounded off, probably from someone using the wrong size wrench before me. I had a quick turn-around for the next lesson, so I grabbed my extractor socket set. It took about 15 minutes of careful work, but I got it out without damaging the hinge. The new bolt went in fine, but it got me thinking about how often we see stuff like this from rushed maintenance. What's your go-to method for dealing with a stripped bolt in a tight spot like that without making it worse?

Bought a $280 borescope for a King Air job and it was the best call I ever made

We had a rough-running engine on a King Air 200, and the usual checks weren't showing anything. I was about to pull the jugs, which would have been a huge job. Instead, I spent the money on a decent borescope. Found a cracked baffle in cylinder #3 on the very first look. Saved us probably two full days of labor and a ton of headache. What other tools have you guys bought that paid for themselves on one job?

Question about the time a duck tried to nest in a 737 wheel well

I was doing a pre-flight walkaround at a small regional airport in Maine last spring and found a mallard duck sitting on a pile of grass and twigs inside the main landing gear bay. We had to call animal control to safely remove her, and now I always double-check for wildlife before signing off on any inspection. What's the weirdest thing you've found during a routine check?

Just realized how much better my shop's tool board got after we started using a simple color system.

About six months ago, our lead mechanic, Carl, got tired of people borrowing tools and not putting them back. He bought a bunch of cheap spray paint in four colors. We painted the outline of each tool on the board and then painted the tool handle the same color. So a red wrench outline gets the red-handled wrench. The change was slow at first, but now, if a blue socket is missing, you spot the empty blue outline instantly. It cut down our 'where's the 9/16' time by a ton. I used to waste maybe ten minutes a day just looking for stuff. Now I just glance at the board. Has anyone else tried something like this to keep their bay organized?

Just swapped from a standard 3/8 ratchet to a low-profile flex-head for a tight spot on a Cessna 172's cowling. The difference was night and day.

Was doing a 100-hour on a 172 last week, trying to get at a nut on the back of the alternator bracket. My regular ratchet handle was too long and the head was too bulky, kept hitting the firewall. Grabbed a buddy's low-profile flex-head from his box, and it slid right in with enough swing. Took 30 seconds instead of 10 minutes of cussing. What other 'tight access' tools have saved you guys a ton of time on light singles?