How to Safety Wire a Tube Coupling Nut|
How to lockwire a fluid fitting
Install Safety Wire A through Hole B in Part C
TYPICAL WORKING CONDITIONS:
- Part C is three feet deep in an equipment bay with a six inch square
- Part C is behind parts D, E, F, G and H.
- You can only see Part C by using a mirror.
- Part C is one inch from the HPT case which is still about 990°F. Ouch.
- It is 11:30 p.m. and quite dark and you have a flashlight in your mouth.
- You are trying to work upside down standing on a stepladder.
- You just dropped Safety Wire A and it fell into the jet intake.
- You just dropped another Safety Wire A and you don't know where that one went.
- Your last piece of Safety Wire A is too short.
- The tool crib does not have any more Safety Wire A.
- The Safety Wire A you have is a larger diameter than the Hole B they
- An old piece of Safety Wire A is stuck in Hole B.
- Your boss is watching.
- Your boss, his boss, an inspector, and the customer are all
- You just now noticed Hole B is completely worn through the side of Part C.
- The weather conditions are "snow turning to freezing rain" and you are in it.
- Hole B is filled with a drop of paint that fell on Part C.
- You are bleeding because another Safety Wire A just stabbed you under
the fingernail. Ouch.
- Your new replacement Part C does not appear to have a Hole B.
- Alright! Who borrowed my safety wire pliers?!?
- Are you sure Safety Wire A isn't twisted too tight?
- Are you sure Safety Wire A isn't on backwards like in the picture?
- Are you absolutely sure that you already tightened Part C?
- It is about 16°F and the wind is NNE at 25 gusting to
40 and you don't have any gloves.
- You are wearing gloves.
- You are wearing Nuclear/Biological/Chemical warfare equipment.
- You are on an aircraft carrier in 40 foot seas.
- You have just done this 12 times and there are 136 more to
- Several of the conditions above apply simultaneously.
- All of the conditions above apply simultaneously.
- OR -
Use the Moeller Click-Loc locking device. The nut was positively secured when you tightened it. You did not need any safety wire. You were done hours ago.
(For more fun with locking devices you can go to the FAA website at
and search the Service Difficulty Reports database. Type in "lockwire", "safety wire", "cotter pin", "lock washer" etc. in the "Problem Description" field and you'll see lots of locking device related problems. Or for even more fun try searching for "fell off".)