Thank you Matkat that is exactly the kind of insight I am hoping for. I think you remember correctly about the corrective aileron. As far as I can see Ken was correcting sideslip by reducing the bank angle with aileron and was in a climbing turn with a bank angle of 30 degrees with normal acceleration of about 2.5 g when the wing failed due to increased loading presumably caused by the horizontal gust Plastic Bonsai mentions. As Fg Off Bloggs and indeed Roy Boot says the fatigue specimen did not reflect the new role of the buccaneer or in fact the new extended wingtips which were having an unexpected effect on the stresses at Rib 80 where the crack originated. It was such a terrible loss and my heartfelt best wishes go to Claire.