Yes Mark's site is very good and has opened up quite a few avenues of investigation, however it is fairly quiet in the demise of the T.Mk.4s.
I am wondering if it is culmination of things leading to a higher than anticipated use of fatigue life. Clearly low level will soon use up life as will aerobatics or increased powerplant weight, especially when coupled with the previous points.
Some have muted modification of the fleet being too costly, any thoughts on that one?
Bob