What are the rudder cable ends made out of?

[newt]

CASA has an NPRM out for an AD which will mandate replacement of any control cable end fitting that's been in service for longer than 15 years if it's made out of SAE-AISI 303 Se stainless, or if its metallurgy is unknown.

So -- what are the Vans rudder circuit cable ends made out of?

CASA NPRM for background: http://www.casa.gov.au/wcmswr/_asset...nprm1303ms.pdf

Pay particular attention to the cross section microscope images, which show cracks radiating from the inside-out, which provide no visual sign until they fail in service.

Is this going to affect us?

- mark

[XOverZero]

Sorry to read about this issue. I hope the terminals made from 303 are not in widespread use. This same matter came up at a company I worked for about 35 years ago. The arena was different (non-aviation) but the use was similar?that of connecting a highly stressed cable assembly. The connector's material specification should have been limited to types 302/304 stainless, but an oversight allowed it to be manufactured from type 303, an alloy that includes traces of sulphur or selenium to make it free machining. These inclusions greatly encourage stress corrosion. In service failures occurred quickly, and a massive recall ensued. No lives were lost, but there were injuries. In all, a very major bummer.

[az_gila]

The RV-6 plans call for a AN668-4 part on the rudder cables.

That part has become a MS20688 spec.

http://www.everyspec.com/MS-Specs/MS...S20668C_34276/

And is made from either 303 or 304 corrosion resistant steel.

Is there an easy way to distinguish between the two alloys on a fabricated part?

[XOverZero]

Originally Posted by az_gila

...Is there an easy way to distinguish between the two alloys on a fabricated part?

Not that I'm aware of.

[newt]

I've sent a quick note to Vans, let's see what they come back with.

- mark

[Alex Edwards]

Looks like CASA have the final AD out now

http://casa.gov.au/wcmswr/_assets/ma...EN/GEN-087.pdf

It seems to apply to both types of alloy.

Alex

[Yen]

CASA have that AD but I believe it is not applicable in USA. FAA hasn't seen fit to follow CASA. In the same way FAA have not had any ADs for inspection of Cessnas for corrosion.
Mike who runs Savvy Aviator has said a few words about CASA who only have to provide safe aviation, whereas FAA has to promote aviation as well.
Flying survives in Australia in spite of CASA not because of it.