But it keeps me learning, and in this short post, I'm sharing a bit of my experience with a cocky phrase I think all of us have encountered at one point.
How hard can that really be?
For me, safety wire was one of those cases. Deceivingly simple, there's a lot more that goes into it that what first meets the eye.
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| An example of safety wire on a fuel totalizer. It looks like twists of wire, but there's much more to that. |
So what is safety wire?
Also referred to as "lock wire", safety wire is what is called a positive locking device. It serves the purpose of preventing a fastener from loosening or falling out, and also serves as a witness that the fastener has been properly torqued.
Also referred to as "lock wire", safety wire is what is called a positive locking device. It serves the purpose of preventing a fastener from loosening or falling out, and also serves as a witness that the fastener has been properly torqued.
That covers the "whys", but what about the "hows"? It's the "hows" where the hidden challenges in the process begin to reveal themselves.
From the Federal Aviation Administration's book AC43.13, here are the requirements for proper safety wire installation on an aircraft.
- Safety wire must be installed in such a way that the fastener cannot loosen.
- Safety wire must have 6-8 twists per inch.
- Never overstress safety wire. It will break under vibration.
- Wire must not be nicked or kinked, that includes backing off twisted wire if you've twisted it too many times.
On top of that, there are diagrams upon diagrams of examples displaying the proper procedure for various types of applications.
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| An example of some safe wire combinations From AC43.13 |
For me, that meant making a lot of mistakes. I've gotten the wire too loose, I've kinked the wire, I've even gotten the direction backward, loosing the fastener instead of tightening it.
And all of that means grumbling in frustration, cutting it off, and doing it again.
So what does that mean for those of you out there? Many of you will never touch safety wire, and that's alright. It may not be your thing.
But one lesson from a few twists of wire can be summed in a few simple phrases.
Just because it looks easy, doesn't mean it is. And if someone makes it look simple, it may be that they've been honing that skill for years.
And that can be true of an task, be it safety wire, welding, running a CAD program, or installing a data management system.
So see the world with an eye for learning from those experts!
Acknowledgements:
We had to do that very same dog and pony show while in the Air Force servicing missiles, bombs and the big fella, nukes. We had to seal the wire with our own specific crimped lead tags that identified the inspector, etc. And forget about the TO (technical orders) for maintenance. Those were more tedious. Six turns of screw RG-021 CCW arriving back to the exact starting position... Multiplied by the hundreds of screws in ONE bomb. Someone reading, someone watching and someone doing. But there's a method to the madness. None of us were turned to "pink mist" faster than the nerve conduction velocity of the human nervous system.
ReplyDeleteWe had to do that very same dog and pony show while in the Air Force servicing missiles, bombs and the big fella, nukes. We had to seal the wire with our own specific crimped lead tags that identified the inspector, etc. And forget about the TO (technical orders) for maintenance. Those were more tedious. Six turns of screw RG-021 CCW arriving back to the exact starting position... Multiplied by the hundreds of screws in ONE bomb. Someone reading, someone watching and someone doing. But there's a method to the madness. None of us were turned to "pink mist" faster than the nerve conduction velocity of the human nervous system.
ReplyDeleteAmen! I'm fortunate enough to not have had to work on something as critical as you did. But you're right in the "method to the madness". It's all designed to make sure the job is done correctly, and safely!
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