APPLICABILITY OF TNS 40
Stik
Just to correct a minor error in your last ..
TNS 40 applies to ALL variants of stainless steel - polished or not, it does not matter.
You are correct to say that TNS 40 does not apply to streamline wires made from carbon steel.
A similar TNS is in course of issue for application to the de Havilland biplane twins - Dragon, Dragonfly and Dragon Rapide. The CAA is about to 'consult' before making this mandatory also.
The mandate for TNS 40 on the single-engined Moths looks like it will be published in CAP 747 at the end of this month.