On Sat, 06 Jun 2009 06:08:46 -0400, Michael Horowitz
wrote:

AC 43.13 para 4-94 says: " WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a patch of the same
material, one gauge thicker" and then defines punctured tubing:
b. Punctured Tubing. Holes are not longer than tube diameter and
involve not more than 1/4 of tube circumference.

Question: Can I apply the definition of Punctured Tubing to mean a
hole caused by rust? As I'm stripping my tubing I've notice several
out of the way patches and I'm assuming they are covering rust holes.
I've uncovered two 1/8" holes previously unseen and am wondering if a
simple patch is correct. - Mike

forget the bloody semantics of the document.
you are repairing a structure that will have flight loads imposed upon
it unrelentingly in flight.

cut the dodgy stuff out and weld in structurally sound replacement
tube.

ask yourself as you work "would I be prepared to do a 60 degree angle
of bank turn at Vne with maximum all up weight with that repair?"

with rust penetrations what is the internal wall of the tube like?

Stealth Pilot