Common Mistakes, shortcomings and Standard Practices

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Greg87
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Common Mistakes, shortcomings and Standard Practices

#1 Post by Greg87 » Mon May 22, 2017 5:23 am

Hello everyone

I'm working on putting together a presentation/document regarding common mistakes we (As AME's) see, standard practices that people don't seem to know (or know, but don't understand) or things that people just don't seem to know, but we wish they did.

I'm aiming to put something together that can be interesting and informative to a variety of experience levels. I know we all have our pet peeves that we wish everyone else knew about, whether they are a fresh apprentice or someone with many years of experience.

Ideally I'm looking for some more complex/specific items. So, rather than "none of the kids coming out of college know how to apply PRC" I'd prefer something like "when rigging control cables, I find people struggle with obtaining equal tension on both sections of the cable circuit. In my experience, the best way to do this is..."

So, I thought I'd check with everyone on here and see if people had any suggestions. I welcome any input, and if used I will gladly reference you in the presentation if you so desire. Please be civil and don't attack anyone who provides input, this presentation is in the interest of sharing industry knowledge/experience.
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PilotDAR
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Re: Common Mistakes, shortcomings and Standard Practices

#2 Post by PilotDAR » Mon May 22, 2017 7:11 am

Maintenance errors I have experienced during maintenance check flights (or attempted check flights):

Weight and balance reports/amendments with terrible errors - no reality check, or sample loading calculations to confirm it makes some sense. Or, the plane should have had some ballast installed.

Flight controls with incorrect travel (stops set wrong) - this is a serious problem for C 206 trim,

Seatbelts installed so that they will not couple, or the shoulder harness will not couple, as it is on the wrong side - AMEs should sit in each seat, and do up the seat belt.

Lockwire or cotter pins not installed

Lefts and rights of instruments or controls for multi engine aircraft not confirmed as being correctly sided. (I once flew a DA-42 with the unfeathering accumulator switches reversed - no wonder the props would not unfeather! I was about to fly an Aztec, until I noticed that the oil pressure gauge connections were reversed.

Wheels which will not turn freely following brake work (not jacked up and checked)

Engine controls rigged with no bounce at full,

Using a single wrench, where two should be used opposed on a pipe or hose connection

Moving parts and wires left so they could chafe

Using cherry max rivets 'cause you're just lazy, and don't want to get in properly to buck a solid rivet, when that is what should be there. The owner should not bear the cost and damage of the future need to remove those "did not need to be" cherry max rivets.

Paperwork vague or incomplete,

And, please wipe off the greasy fingerprints.....

Owners bear some responsibility too - they must be willing to pay for good work to get it, and not nickle and dime AMEs/AMOs, so there is paid time to get things right, and check them!
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Big Pistons Forever
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Re: Common Mistakes, shortcomings and Standard Practices

#3 Post by Big Pistons Forever » Mon May 22, 2017 11:54 am

Leaving tools behind. I have twice found tools left behind once on the cockpit floor under the instrument panel and once under a seat. It is a good idea to have a good look around inside the cabin before flying an aircraft just out of maintenance.

AME's are human and it only takes some momentary distraction to miss picking up a tool as you are buttoning up the job. Pilots have a roll to play in maintenance safety.
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digits_
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Re: Common Mistakes, shortcomings and Standard Practices

#4 Post by digits_ » Mon May 22, 2017 12:21 pm

Big Pistons Forever wrote:Leaving tools behind. I have twice found tools left behind once on the cockpit floor under the instrument panel and once under a seat. It is a good idea to have a good look around inside the cabin before flying an aircraft just out of maintenance.

AME's are human and it only takes some momentary distraction to miss picking up a tool as you are buttoning up the job. Pilots have a roll to play in maintenance safety.
Rags seem to disappear as well: pulled one out of an engine cowling after a 100 hour check once and one that was tangled in an aileron pulley after some dashboard/cockpit work.
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GyvAir
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Re: Common Mistakes, shortcomings and Standard Practices

#5 Post by GyvAir » Mon May 22, 2017 3:03 pm

We could all write a proper laundry list on this topic, I'm sure. I'll limit myself to a couple suggestions that apply to just about every aircraft out there.

Learn how, when and where to use a multi-meter, how to isolate parts of a circuit for testing and what the difference is between ohms, amps and volts at the very least. I'm sure for a lot of students, that class quickly became a bit of a muddled blur. Take the time now to sort it out in your head. Look up some tutorials online. Buy yourself a science lab kit. Invest in a 1970s MGB and try to keep its lights on in the rain. Whatever it takes to get comfortable with using one and what you’re looking for.

Torque wrenches. They are not magic wands that will give you accurate results with no thought or skill applied by the user. Technique is important! As is understanding things like the differences between course and fine threads, wet and dry torque (proper lubricant for the application), running torque, breakaway torque, adapter angle/ length, sequence, step torqueing… and how all these factors affect the actual torque applied and the proper compression of the material under the fasteners.

(And please… the torque charts in your little blue book reference the thread size, not the wrench size)
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helicopterray
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Re: Common Mistakes, shortcomings and Standard Practices

#6 Post by helicopterray » Tue May 23, 2017 5:03 pm

Use day/month/year format such as 10May2017. Don't use 10/05/17, I may not know what you're referring to as the day/month/year.

Route wiring harnesses above fluid lines. I worked with an AME that had never heard of that concept.

If you're going to walk away for something in the middle of a project, (washroom break, lunch, etc), put a flag on what you were working on last. You can come back to that point when you return. Don't rely on your memory. Ever.

If you're working by yourself and there's no AME around, have your pilot do a thorough check before first start. Point out everything you did.
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photofly
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Re: Common Mistakes, shortcomings and Standard Practices

#7 Post by photofly » Tue May 23, 2017 7:28 pm

GyvAir wrote: ...what the difference is between ohms, amps and volts at the very least. I'm sure for a lot of students, that class quickly became a bit of a muddled blur.
You are joking, right? People who don't have that clear in their heads are allowed to work on airplanes?
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GyvAir
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Re: Common Mistakes, shortcomings and Standard Practices

#8 Post by GyvAir » Wed May 24, 2017 9:06 am

photofly wrote:
GyvAir wrote: ...what the difference is between ohms, amps and volts at the very least. I'm sure for a lot of students, that class quickly became a bit of a muddled blur.
You are joking, right? People who don't have that clear in their heads are allowed to work on airplanes?
Yes, but not without supervision. Those that can't get such things clear in their head as an apprentice hopefully move on to occupations better suited to their personal aptitudes.

On a related note I've got a couple more skills to add to the list that some people need to work on:

1. Know your limitations and ask for help or clarification sooner rather than later. Don’t worry; nobody knows everything. It’s always going to be better to ask early, before wasting hours or breaking something.

2. Own your mistakes. We all make them. Trying to cover up or denying responsibility will always be exponentially worse than the original mistake itself.
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