Safety wire diameter

[rturbett]

Aircraft spruce is giving me 5 choices of wire diameter.

I'm looking for the appropriate diameter for safety wiring the oil filter, but also interested in a tutorial that educates on the different uses/ purposes for the variety of diameters. I haven't seen the call out in the the service manual or parts catalog -though I admit to not reading every page.  Any thoughts are appreciated.

Rob

[EricJ]

3 minutes ago, rturbett said:

Aircraft spruce is giving me 5 choices of wire diameter.

I'm looking for the appropriate diameter for safety wiring the oil filter, but also interested in a tutorial that educates on the different uses/ purposes for the variety of diameters. I haven't seen the call out in the the service manual or parts catalog -though I admit to not reading every page.  Any thoughts are appreciated.

Rob

0.032 is the most common and used for most things, like securing the oil filter.    Once on a while there's something more heavy-duty that requires 0.041, and some little-bitty things use 0.025, especially if 0.032 would be too thick to maneuver in the available space.    The 0.020 is mostly used for things like emergency windows and throttle limits (on engines with emergency power), where the wire is mostly just a tell-tale whether it has been used, since it can be broken easily if needed.   e.g., on some WWII bombers there was additional "emergency power" that was available by just pushing the throttles past the 0.020 wire and breaking it.   The mechanics needed to know if it had been used because it changed the overhaul time limits on an engine where the emergency power had been used, and the wire let them know.

An MS member with a C310 discovered a couple annuals ago that the pilot emergency egress out the side window was safetied with thicker wire and probably wouldn't have been usable if needed, because it probably wouldn't be possible to break the wire that was used.

The SMM often says what wire to use if it is something other than 0.032.

 

[Fly Boomer]

22 minutes ago, EricJ said:

0.032 is the most common and used for most things, like securing the oil filter.    Once on a while there's something more heavy-duty that requires 0.041, and some little-bitty things use 0.025, especially if 0.032 would be too thick to maneuver in the available space.    The 0.020 is mostly used for things like emergency windows and throttle limits (on engines with emergency power), where the wire is mostly just a tell-tale whether it has been used, since it can be broken easily if needed.   e.g., on some WWII bombers there was additional "emergency power" that was available by just pushing the throttles past the 0.020 wire and breaking it.   The mechanics needed to know if it had been used because it changed the overhaul time limits on an engine where the emergency power had been used, and the wire let them know.

An MS member with a C310 discovered a couple annuals ago that the pilot emergency egress out the side window was safetied with thicker wire and probably wouldn't have been usable if needed, because it probably wouldn't be possible to break the wire that was used.

The SMM often says what wire to use if it is something other than 0.032.

 

Nice post!

[N201MKTurbo]

24 minutes ago, EricJ said:

0.032 is the most common and used for most things, like securing the oil filter.    Once on a while there's something more heavy-duty that requires 0.041, and some little-bitty things use 0.025, especially if 0.032 would be too thick to maneuver in the available space.    The 0.020 is mostly used for things like emergency windows and throttle limits (on engines with emergency power), where the wire is mostly just a tell-tale whether it has been used, since it can be broken easily if needed.   e.g., on some WWII bombers there was additional "emergency power" that was available by just pushing the throttles past the 0.020 wire and breaking it.   The mechanics needed to know if it had been used because it changed the overhaul time limits on an engine where the emergency power had been used, and the wire let them know.

An MS member with a C310 discovered a couple annuals ago that the pilot emergency egress out the side window was safetied with thicker wire and probably wouldn't have been usable if needed, because it probably wouldn't be possible to break the wire that was used.

The SMM often says what wire to use if it is something other than 0.032.

 

FWIW. The 310 window is supposed to be rigged with 0.010 copper wire. It was rigged with 0.020 stainless wire. It was impossible to open.

[EricJ]

6 minutes ago, N201MKTurbo said:

FWIW. The 310 window is supposed to be rigged with 0.010 copper wire. It was rigged with 0.020 stainless wire. It was impossible to open.

0.020 copper is usually referred to as "breakaway" wire, so somebody probably thought it was a "reasonable" substitution.   

[rturbett]

35 minutes ago, EricJ said:

0.032 is the most common and used for most things, like securing the oil filter.    Once on a while there's something more heavy-duty that requires 0.041, and some little-bitty things use 0.025, especially if 0.032 would be too thick to maneuver in the available space.    The 0.020 is mostly used for things like emergency windows and throttle limits (on engines with emergency power), where the wire is mostly just a tell-tale whether it has been used, since it can be broken easily if needed.   e.g., on some WWII bombers there was additional "emergency power" that was available by just pushing the throttles past the 0.020 wire and breaking it.   The mechanics needed to know if it had been used because it changed the overhaul time limits on an engine where the emergency power had been used, and the wire let them know.

An MS member with a C310 discovered a couple annuals ago that the pilot emergency egress out the side window was safetied with thicker wire and probably wouldn't have been usable if needed, because it probably wouldn't be possible to break the wire that was used.

The SMM often says what wire to use if it is something other than 0.032.

 

Thank you- perfect explanation!

[GeeBee]

It also depends on the material when using breakaway wire. For instance plastic switch guards need to be copper.