Many thanks guys, obviously a well known weak link, information certainly never filtered down to we pilots in our military or civil when I was employed in both, spent a lot of time in the civil sheet metal shop between flights helping reskin 205 and 212 tailbooms, me on the gun and the expert on the bucking bar, did a bit on a 76 tail boom once as well. Good practice for when I and two of our engineers when on to build three RV's.