Least Favorite Maintenance Tasks

[60FltMech]

Mechanics/Technicians, thought about starting a thread on this topic this morning: what’s the least favorite maintenance task on the particular helicopter(s) you’ve worked on?

For me it’s as follows:
AH-64 Apache, 3 point safety wiring for canopy jettison initiators, have to lay upside down in cockpit floor and use a mirror. Then hear QC tell you “looks beautiful! Too bad you did it backwards” because, mirror!🤣

CH-47 Chinook:
Hydraulic System Purification post phase. Sit around waiting for 30 gallons of hydraulic fluid to filter(4+ hours) til the water content was down to below 10 parts per million. Really. Knowing that the first time you pop open a brand new can of 83282 and service the system it’s gonna have 30 plus parts per million in it.

UH-60 the “30/30”, 30 minute ground run/30 minute hover for transmission serviceability check after chip light. We call it doing a “penalty run”. 🤣 And blade de-ice systems checks. Adjusting/safety wiring the tail rotor control quadrant stops in the cabin ceiling. Adjusting collective balance springs(soon to be a thing of the past, last 10 60L’s leaving before the end of the year, YAY! Hooray for collective trim actuator on 60M)🤣

I’m sure I’ll think of more, I’ve probably blacked them from memory. Some that I thought were bad when I was an Apprentice Mechanic are no biggie now, funny how perspectives change with knowledge/experience.

Curious to see what others have to share!

FltMech

[SASless]

Has changing a Utility Hydraulic System Manifold gotten any easier. on the Chinook.

Used to take two people....one inside reaching up through the access panel with a single hand and unable to see what the hand was doing....and one up above looking down giving verbal directions.

I forget how many connections there were but it was pushing twenty or so as I recall.

Then on the Huey....212/412.....there was the infamous "Hell Hole" and its myriad of hydraulic and oil lines....all of which leaked....into which one had to crawl under the aircraft then wiggle up into said "Hole"

[60FltMech]

SASless,
Oh yeah, I forgot about that one! This task is exactly the same as you remember. we did a #2 manifold one time(opposite side of the pylon), a Rosan fitting blew out of the manifold body, emptied the #2 system. We robbed a complete manifold from a deadlined aircraft and took is out to the downed aircraft at the stagefield(Goldberg) and commenced to change it.

it was quite cold out, and windy. I had Carhartt coveralls on folded up in the access on the right side of the pylon and my partner was on the other(windier side) Fun times.

Funny side note: when we tore down the damaged manifold the transfer the parts across to a new manifold body a couple months later the return filter was completely full of brass colored metal shavings. In 22 years I’ve never seen a more plugged up filter. And that’s a big filter, as you know.

We showed the Maintenance manager what we found and he immediately pulled the aircraft down for a hydraulic purification, which was a big deal as we only had like 9 flyable aircraft out of 32 at the time!

Ahhh, the bad old days…

FltMech

[roscoe1]

Replacing fuel cells on just about medium or large helicopter and then seeing no drips you go home happy, only to find a puddle in the morning. Then you get a deserved reaming from your domestic partner for putting jet.fuel smelly clothes in the machine at home, thereby making it a bad day all around. Better yet, on an AW 109E, I once had to put 3 different NEW fuel cells in before I got one that didn't leak right through the fabric but not until they had been in service for a day or two. These were not pin holes but whole sections of bonded bladder that just leaked. And another one, is putting a self sealing tank into an OH-58, especially if the bladder is a little old. Like putting 10 pounds of you know what into a 5 pound bag.

[212man]

I think single engine change in a 212 was not a favourite as I recall. The whole twin pack change idea didn’t gel with the commercial world….

[wrench1]

: what’s the least favorite maintenance task on the particular helicopter(s) you’ve worked on?
Hmmm... where to start.

- Track and balance -100 series 412 M/R blades with original RADS.
- Rotorbrake change AS355
- Any electrical issues AS355
- One piece windshield change AS350 during winter.
​​- Trying to snap upper snaps on old BO105 main fuel cell AND getting the interconnect "donuts" to seal
- Cleaning/inspecting floor tunnels on EMS BO105
- Chasing a torque split on a 222 with 101-650s installed
- C-box change 212 without modified support.
- Bleeding oleo struts on SA315B
- Replacing main fuel cell 206L without the "zipper" opening.
- Packing Hughes 500 floats
- Packing BO105 factory 4-pack floats
- Packing S76 floats without a board
​​​​​- Any maintenance I needed to take a boat to get to.
- And........

Almost makes me want to go back to work.... not. But we sure had fun.

[SASless]

Anything to do with the front end of the S-58T.....that required removing all of the ductwork.....which resembled a HVAC ducting nightmare.

[roscoe1]

I'd forgotten that one. 58T is where I learned to hate stainless steel cam-locs in hard to turn places. Still have a couple of scars from that sheet metal.
Working on the AS350D model electrical wiring before people got smart and went to circuit breakers and ring terminal blocks was always a joy. What were the engineers thinking? And who decided that wires on landing lights lamps should be so short that you can barely get to the screws? Also, don't get me started on changing out old cyclic trigger switches, Chinese hat switches, etc. that have been changed a couple of times and the wires just keep gettin' shorter........

[megan]

In our organisation I'm sure they would have said getting a pilot to do the post maintenance ground run or flight, they seemed to run for the doors or come up with some excuse, I'm waiting for a phone call was always well used. Me, I jumped at the chance as it got one away from crew room politics. If it needs any explanation pilots were staff and subject to a yearly appraisal for a pay rise, politics ruled, helping maintenance was not some thing on managements radar.

[60FltMech]

Loving the responses so far!

Someone said above “makes me want to go back to work…not. But we sure had fun!” That’s the truth! Some of the least favorite or hard task had the payoff of the feeling of accomplishment when you did it quicker than the other guy.
I remember removing a #2 engine fuel control off a Chinook without pulling the engine (T55-GA-714) just to see why nobody did it that way. Turns out there’s one safety on a bolt that is REALLY easy with the engine removed, not so much when it’s installed. 🤣But, we got it done.

Or the camaraderie of the team you are working with being told, “I bet you can’t…” Challenge accepted! Locked out forward head on a Chinook, Measured axial play on the swashplate drive link and reconnected pitch links with logbook entries cleared in 23 minutes because this one Nitpicking Flight Engineer never wanted to fly.

Someone else said something about RADS, thought about that yesterday as we were doing 120 hour vibe checks on a UH-60M. IVHUMS is such a wonderful thing, no more running wires all over the aircraft with an AVA kit(what the Army calls RADS), hooking em into the DAU and then having a bad wire, accelerometer etc or bad CADU.

Now everything is part of the aircraft, and it works great.

FltMech

[Sloppy Link]

Pilot task - Fitting/Removal of dual collective and cyclic on an EC135 when blessed with hands and fingers the size of an adult gorilla.

[ZoltN]

Some examples from the MD900:


- removal of the NOTAR Fan Drive Shaft; you have to work lying upside down in the NOTAR inlet to remove the several fairings then the four mounting screws at the bottom of the shaft (assuming that that the NOTAR Fan is installed). The shaft itself is a thin walled aluminum part, so you have to be extremely careful not to damage it while sliding it through a narrow cutout towards the transmission.


- you need to perform fuel transfer and fuel tank integrity test every 100 hours. The tests take about 20-30 minutes each; however, it may take several hours to set the initial fuel levels required for each test through the two small fuel drain valves at the bottom of the fuselage.


- when the test fails, you have to remove the forward cabin floor panel to gain access to the fuel tank. The floor panel is installed with more than 100 screws and bolts (Air Methods universal floor panels). If the helicopter has the center console extension towards the rear, eight bolts will be installed within the console. You have to remove all console installed equipment in this area and somehow reach through the cables and connectors to remove these bolts. This task is not for mechanics with large hands.


- on each annual, you have to disassemble the landing gear, remove the paint from the crosstubes, inspect them with a 10x magnifying glass from outside and with a borescope from inside, and have them NDT-ed. Then, of course, apply new primer and topcoat before reassembly. It is really disappointing when, after all this, the crosstube fails during a normal landing a few months later...


- almost all work on the Automatic Flight Control System/EFIS/IFR instrumentation STC; not because it is so badly designed, but because it is so badly documented.

[airsail]

Almost any corrosion repairs on an older AW139, you have to wear blinkers so you can concentrate on the area you are repairing and not all the other areas that also need attention. 0.012” honeycomb skins, if you see bubbles, it’s already through to the core, grrr.

[wrench1]

I jumped at the chance as it got one away from crew room politics. .
We were fortunate that most pilots didn't mind mx flights unless you disturbed their safety nap. Then they never made it through their pre-flight. To mitigate, we kept a maintenance stand outside the pilot trailer window to recon the situation prior to entering.

roscoe1= Working on the AS350D model electrical wiring before people got smart and went to circuit breakers and ring terminal blocks was always a joy. What were the engineers thinking?
All the Aerospatiale engineers were on loan from the Renault truck works. They brought that cutting edge 100 year old technology with them to include that truck horn for the hydraulics switch. What was even more fun was dropping the overhead fuse panels on a AS355.

[helofixer]

Tail rotor servo change on Bell 407....more fun with an ems or police ship and air conditioning. They love to cram stuff in the way. You can barley touch it from the tail boom access panel. Cant hardly reach it from the baggage compartment roof access panel. you will be removing racks and boxes and other crap. Not for husky mechanics, which of course I am one. :O

[Saint Jack]

Ref. Megan, Post #9 (and at the risk of thread drift) You said, "....getting a pilot to do the post maintenance ground run...." Why couldn't you do a ground-run yourself?

[RVDT]

Almost any corrosion repairs on an older AW139, you have to wear blinkers so you can concentrate on the area you are repairing and not all the other areas that also need attention. 0.012” honeycomb skins, if you see bubbles, it’s already through to the core, grrr.

Seen that on a recently "offl-lease" offshore machine quietly imitating a selzer tablet in the corner of the hangar.

[RVDT]

All the Aerospatiale engineers were on loan from the Renault truck works. They brought that cutting edge 100 year old technology with them to include that truck horn for the hydraulics switch. What was even more fun was dropping the overhead fuse panels on a AS355.

Pretty sure the fuel cap on a 350B came in a Peugeot box with a Peugeot part number.

You needed a "transverse lobotomy" prior to working on them so you could think like a Frenchman!

[Salusa]

Hmmmm..

Fuel Nozzles on PT6 Bell 212/412. If centre firewall is modified not to bad, but with my Sausage Fingers still a PITA
206L3 Transmision Restraint Support.
Pretty much any Fuel tank aft of first Hell Hole 212/412 (412 even worse)
Anything on a MD500E for me. Especially front of engine.
AW139 Floats.

[wrench1]

Pretty sure the fuel cap on a 350B came in a Peugeot box with a Peugeot part number. You needed a "transverse lobotomy" prior to working on them so you could think like a Frenchman!
Ha. But don't know if a lobotomy was enough with some items. Never seen a Peugeot/Renault box but have seen pic-tickets or the part itself stamped with vehicle brands on AS parts. The factory nose external load mirrors were everyday truck mirrors and the Lama ones I saw had Renault stamped on the back of the mirror. But no different than the Castrol oil used for EC135 transmission, same stuff for a Mercedes except for that LBA sticker on the back and an increase in price. Not a bad thing really as they've used vehicle parts rebranded as aircraft parts in aviation for eons.

[ericferret]

Ha. But don't know if a lobotomy was enough with some items. Never seen a Peugeot/Renault box but have seen pic-tickets or the part itself stamped with vehicle brands on AS parts. The factory nose external load mirrors were everyday truck mirrors and the Lama ones I saw had Renault stamped on the back of the mirror. But no different than the Castrol oil used for EC135 transmission, same stuff for a Mercedes except for that LBA sticker on the back and an increase in price. Not a bad thing really as they've used vehicle parts rebranded as aircraft parts in aviation for eons.

Hughe 300 used commercial transmission oil and truck fifth wheel grease (Shell Alvania) for the engine drive shaft.
S76 used Dexron II in the main gearbox, automotive transmission fluid.
I dont see a problem with using commercial parts if suitable. Its the price mark up that is the problem!!!

[megan]

Nothing wrong with the use of non aviation specific parts if approved by the authority, once flew a brand new fixed wing whose production fuel cap came from a Ford Falcon as did the coil spring used on the nose wheel. The Dextron oil was developed for GM and its automatic transmissions, we had problems using it in the 76 as after some hours had been accrued in hot weather we suffered a loss of oil pressure yet the oil still passed all the specification tests, presumption by the scientific folk was that in being forced through the transmission oil jets the long chain molecules were being chopped into shorter chains, I'd have thought that would make for a loss of viscosity but apparently not. We swapped to Mobil Jet, no further problems.

[Mee3]

Many air conditioning compressor and condenser are rebadged Denso.

[brett s]

The 3 dynamic absorbers in the nose & under the cockpit seats of a CH-47 were no fun to replace - heavy & awkward. Sounds like they finally got rid of them in the F models & are using a much lighter active unit.

[Rigga]

Whirlwind Intermediate (Inclined) Gearbox mounting bolt - wire-locking! - 2 inches away from a 1 inch hole…

Chinook Mk1/D hyd and lube flexible pipe routes around the Aft XMSN….Wha!!!!

[Dave B]

A bit off thread, but there was a famous case in the RAF when the venerable Whirlwind was still on SAR duties. A new fitter straight out of training reported in, and the sergeant said, "Right lad go and do a Kerosene wash on that engine" so lad goes and gets a compressor wash rig, and fills it with neat Kerosine, after fitting the rig to the engine, the pilot says OK after lighting to ground idle, the lad turns the rig on full, the result can be imagined.
It was the sergeant who got the severe rep, he should have checked the lad knew what he was doing.

Another much older RAF story is of a fitter cleaning a Magneto in a bucket of Avgas, he spun it over, thus destroying an aircraft.

[OvertHawk]

A bit off thread, but there was a famous case in the RAF when the venerable Whirlwind was still on SAR duties. A new fitter straight out of training reported in, and the sergeant said, "Right lad go and do a Kerosene wash on that engine" so lad goes and gets a compressor wash rig, and fills it with neat Kerosine, after fitting the rig to the engine, the pilot says OK after lighting to ground idle, the lad turns the rig on full, the result can be imagined.
It was the sergeant who got the severe rep, he should have checked the lad knew what he was doing.

Another much older RAF story is of a fitter cleaning a Magneto in a bucket of Avgas, he spun it over, thus destroying an aircraft.

There was a more recent event in UK where an EC135 was severely damaged when the comp wash was carried out using waste Jet A1 rather than de-ionised water by mistake!

[Winnie]

Purge greasing the rotor head of the 212... one tube in each grip... my hands still hurts from squeezing so many times in a row...

[wrench1]

Purge greasing the rotor head of the 212... one tube in each grip... my hands still hurts from squeezing so many times in a row...
I dont know which would be considered worse, wiping oil and changing seals regularly on a oil lubed head or having to purge grease on occassion. Having done both I think I'll stick to purging grease.

[SASless]

Greaed Heads....ah....memories of bales of greasy rags from wiping down Alouette and Llama rotor heads.....tail booms and tail rotors.

Then there was the added pleasure of undoing the mess and out of balance issues from leaking grease seals.

Loved flying them....but rag wiping was a full time job it seemed.

[wrench1]

Greaed Heads....ah....memories of bales of greasy rags from wiping down Alouette and Llama rotor heads.....tail booms and tail rotors..
They were the only aircraft I ever worked on that reminded me of working on diesel engines: oil, grease, and fuel. And not to mention the task of changing TR stack bearing in the bush and having to wait for the cook to finish the morning bread before we could commandeer his oven to heat the bearing housings.

[SASless]

Ah yes.....the stack bearings and do remember the put the tail rotor blades on in the correct direction of rotation!