flight control turnbuckle lockwire

[qa guy]

came across something interesting today.....
I (along with the other AME's in the shop) were taught that primary flight controls (usually 1/8 cable)
were lockwired with .040. Secondary controls (often 3/32 cable with small pistons) can be lockwired with .032.
According to AC43.13 ch. 7-45 there is no mention of .032 or .020 at all, and that all turnbuckles must use
.040 or greater. Was this recently changed in AC43.13? Our copy in the shop is the most recent. Does anyone else feel that lockwiring a 1/16 trim cable with .040 is
complete overkill? Has anyone come across any maintenance manuals that specify differently?
Any positive feedback is appreciated

[Bulawrench]

This has been the case for years as far as i know but when using .040 on trim cables it tends to bend the terminal end of the cable.
I think .032 is fine as long as the method is correct.

[SeptRepair]

Great question QA. Never gave it any thought. However, if you read your AC 43 carefully it states to use 0.040 copper or brass wire for locking 1/16 and 3/32 cables. The 1/8 and larger to use S.S. 0.040. I wont be changing my technique any time soon though, and will continue to use 0.032 for the smaller cables like Bula.

[culver10]

Aircraft Spruce still sells 0.040" brass lock wire. It is WONDERFUL to use on the smaller cables! If you have never tried it, you should. It does not seem to poke the fingers and draw blood as much as SS also. It is very soft and easy to form.

[iflyforpie]

I always used 0.040 single-wrap on everything down to 1/16" cables because of what AC43.13 says. But I've never seen a problem with 0.032 lockwire on smaller turnbuckles I've taken apart and it sure is a lot easier.

What method are you using with the 0.032? Sometimes a big single-wrap is just easier to do than a small double-wrap (or heaven forbid a spiral wrap).

Sure do miss the clips on the Boeings.

[qa guy]

thanks for the great feedback!
I currently use the single wrap. on the re start cessnas they use clips. AC43.13 does state lockwire
can be substituted for clips, but does not say the opposite.

[Fox 3]

funny, the Jetstream actually says to ONLY use clips, and not lockwire. I like lockwire personally but the clips sure easy if everything's lined up right.