Trickiest mx task

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Dave Taylor
For example; what is the most difficult aircraft fastener you have ever had to tackle?
ie, you couldn't see or feel it but you were still able to get a tool on it for removal/tightening/adjusting.
Or; there is no ordinary tool that can tighten/loosen it but you were able to make one that worked.

It is my opinion that most a/c designers never had occasion to do much work on aircraft!

That 4th nut on some dry vac pumps?
The oil reservoir on the O-200?
The 4th nut on the IO520 intake riser?
Some insignificant part that requires major disassembly to access?
 
Mine would have to go to an Mu2's air cycle machine. I think it took me almost 6 hours to service it. Uggg never again.
 
But seriously, changing the boost pump on my Bonanza was seriously frustrating; so many hard lines which had to be installed at exactly the correct angle prior to placing the pump into the bracket (which had to be aligned properly) and into the plane. Most fittings inaccessible once installed, so alignment modification not possible in situ.

Imagine just how happy I was when I realized I'd installed it flowing backwards!
 
Our mechanic particularly had a good sized scowl when we said we had a bladder failure and we had L/R tanks. Apparently that last hanger clip is a really difficult reach for anyone without ape arms.
 
Fuel cells on old Barons come to mind. Getting the inboard snaps that hold the cell up can be a bear unless your knuckles drag the ground.
 
Initial Oil drain plug on my T206H. Wish I had popcorn as I watched the first oil drain before the new one was put on. All the custom hoses and funnels put together "came from together" in seconds resulting in 9 quarts on the floor :eek: Glad I didn't have to clean that up.
 
The 4 tiny nuts on a top row instrument that needs to be removed and reinstalled will give arthritic fingers fits. As if laying upside down in a narrow space with seat rails denting your spine wasn't fun enough.
 
The two bolts mid spar removing the strut on a Cherokee 140

or (and still in the fastener mode)

the staple which holds the PMA and the STC for a Plane Power Alternator
 
These days it can be getting the new tool you just bought out of the super tough, heat stitched, vacuum formed plastic shell it came in without sending yourself to the ER.
I use my band saw. Works out my frustrations with these packages every time!
 
Removing the right side mounting bolts on the AH-64A APU, to include doing the safety wire blind. Had to bear hug the damn thing to get at it while laying on the catwalk. I'd rather climb into the fuel tank fully suited to removing those fittings than have to tackle that again (did the fuel tank trip twice during phase maintenance checks). :confused:

Cheers,
Brian
 
Fuel cells on old Barons come to mind. Getting the inboard snaps that hold the cell up can be a bear unless your knuckles drag the ground.
Cessna 182s have the same issue. BTDT. However, the all time champ PITA project is stripping and prepping a plane for paint. BTDT as well.

Dave
 
Haven't had to do it, but I hear the Comanche gear solenoid is a true beatch. Pilot side, inside firewall near the top. Looks like the first thing mounted, and the rest of the airplane was built around it.
 
Resealing wet wing fuel tanks on a c-182. Also installing and then playing guess and adjust for new brackets and receivers on the 11 firewall cowl mounts on the 172.
 
Gee! So far, no one has mentioned extracting money from the owner's wallet. :rolleyes:
 
Ughh, some frustrating ones here.

Mine was the Lycoming O-145 head bolts. had to grind down the thickness of the wrench and then cut the handle in half to get it into the small space available and make it turn a few degrees. Hard to over torque it but with a 70 year old engine someone has been there before you thinking if tight is good tighter is better...... until it's not !@#$%^ ;-)
 
It took a team of 3 of us (one an aircraft mechanic) about 8 hours to change out the auxilary tank fuel senders on a swift this weekend. I would say the wing removal/installation was about 5 hrs total. We ran into a few small, worn out parts that needed to be replaced along the way, sucking up time. There were some fasteners in tight spaces, but nothing too bad.
 
Muffler shroud on my continental,also oil filter.
 
Solar APU fuel pump shaft in a Hawker.
First time, two days by feel and mirrors,
Sitting in the hell hole. After six times
I got it down to a day. There are some really good reasons I hate Hawkers!
Dave
 
Any fuel tank repair on the outboard auxiliary tanks on a Douglas DC-8. Guaranteed to be in the claustrophobic area between the ribs supporting the outboard engine pylon. Strangely, I never got stuck in the outboard aux tanks. However, I got stuck in the larger pump house of the number 3 tank. Nothing motivates you more to get an engineering degree than a crappy job like that.

On GA aircraft, installing a screw on an instrument panel in the narrow space between existing components, where the nut must be hand held during engagement. This involves contorting your hand, arm and wrist around to the back, while simultaneously turning the screw from the front. Then the nut drops - not on the floor in front of the rudder pedals, but into oblivion down the center pedestal. Then you need to explain why it's taking so long to do your "5 minute job". When you finally fish it out, you bring out several other nuts and misc pieces of FOD which previous mechanics weren't so concerned about.
 
To take the fuel selector out of a Cardinal requires a little magic. The panel under the belly is between ribs but the selector itself is up against one rib so it requires one wrench coming in from the bottom while the other wrench comes in from the floor access panel above.
 
Any fuel tank repair on the outboard auxiliary tanks on a Douglas DC-8. Guaranteed to be in the claustrophobic area between the ribs supporting the outboard engine pylon. Strangely, I never got stuck in the outboard aux tanks. However, I got stuck in the larger pump house of the number 3 tank. Nothing motivates you more to get an engineering degree than a crappy job like that.

When you get into that position you know for a fact that the b@$+@rd that designed it never had to fix anything in his rotten life.

That's why I consider myself VERY lucky to go directly from wrenching on airliners on the DAY I graduated into an engineering job. It gives a design engineer a GREAT lesson that some poor clown is going to have to fix this damned thing some day and PLEASE design it to fix it. jw
 
Inboard exhaust manifold nuts after 1000 hrs on a turbocharged lycoming
Cessna 210 landing gear/fuel pump micro switch machine screws.
Anything on a Mooney:)
 
Telling the owner his engine is crapped out.
 
trying to get block #3 stamped by the FSDO
 
Found out Saturday that removing the stabilator from a Cherokee 140, all by your "oncey" can get a little tricky, but doable.
 
Not as difficult as a few of the tasks said so far but safteying the prop bolts on a garrett TPE331 with the beta ring installed can be a pain, or installing a bladder in a 182 and other such aircraft.
 
Trickiest fastener was a 5/8" hi-lock that went down through the upper wing surface to a MLG actuator retract fitting underneath in the wheel well of an L-1011. Hi-locks have an interference fit, hole had to be reamed, fastener was soaked in liquid nitrogen to shrink the OD and it had to go in in one shot. If it bound up at half mast, warmed up and expanded, the machine shop would probably have been called to remove it.

Most elaborate sales job to an inspector was selling the check out of a Jetstream 32 capacitance FQIS using procedures written for a Smiths Tester on a Barfield box. Sometimes you get to be hero for a day because the wild ass out of nowhere thing everyone needs just happens that off the wall thing you spent a lot of time learning about just by chance.
 
1.) Installing, then safety wiring the #2 Ng tach generator on a T-400-CP-400 installed on a UH-1N. You do it standing on a stepladder, or 5gal bucket with your back against the fuselage, leaning backward, hands over head. You can't see it. You have to do it completely by feel.

2.) Adjusting the audio gain on the RadAlt aural warning amplifier on the A4-E. You do it upside down in the pilot's seat (make sure all the pins are in). It was easier with 2 guys, one would stand on the boarding ladder with a helmet or headset on, with power on the aircraft and the radalt bug set above the minimum setting, so he could tell the guy upside down when it was set right. One pilot's "just right" was always another's "too low" -go figure!

These were "tricks" you learned, that other people would wonder aloud, "how the heck does he do that?" But, once you've done it a couple of times, it doesn't seem that hard.
 
I had to do something to wing wiring at a front spar feed through on a DC-9 wing once. It was the tightest position I've ever worked in. Company policy was thankfully, all wing tank dives required two people, one for safety and one for the dive. It was dry bay boost pump wiring I think, (long time ago). I had to go in head first, upside down, it was just wide enough for my arms to remain stretched over my head. No way to get out on my own, my teammates had to pull me out. Really it was the most claustrophobic spot I ever worked. In those days, I was a thinner man. I regularly spent days at a time inside 727 tanks too. Every D check seemed to involve a FQIS wire harness change.
 
Elevator universal joint replacements on an Aerostar was my least favorite job.
 
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