whgates3 already touched on the anectodal evidence of the structural integrity issues of the P-51.
Here are two quotes and references:
A particularly alarming problem, to say the least, was the occasional tendency of the wings to fall off during a high-speed dive. Ironically, Tommy Hitchcock, who had done much to promote the Merlin Mustang, was killed over England in a P-51B in this way in April 1944. These structural failures proved to be due to the tendency of wing ammunition doors or the main landing gear to open under high-gee conditions, producing excessive forces on the wing. These problems were eventually resolved.
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The generally heavier engine and airframe and the additional fuel also reduced the structural design margin of the P-51, so that the pilot's allowable load factor was reduced from 8 to 6.33. Structural failure was to be a continuing problem for the P-51 on operations. Failure of the landing gear locks allowed the gear to extend and caused an early spate of wing losses. Even after the problem had been fixed, failure of both the wing and the tail continued at a reduced rate. Losses to this cause ran up to an airframe a week. One airframe a week out of over a thousand aircraft being flown in combat and routinely exceeding recommended design limits was considered an acceptable rate at the time.
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I don't have ready access to P-51 archives so won't attempt to comment much more. If the anecdotal evidence is pretty consistent then perhaps AH is attempting to model this tendency?
Tango, XO
412th FS Braunco Mustangs
