[bongodriver]

1) Was the AAIB the only one actually called to investigate on accidents?
2) How many accidents were not reported?
3) We don't know the AAIB method of investigation: did they need the wreckage?... or they could investigate by interviews with the witnesses of the accident?
4) As you says, I repeat, I can be that some accidents not reported as result of a past investigation. A plane is losing its wings during recovery from a dive? The first accident of this kind required an investigation, probably also the second one... but how many until it's clear that the plane can be pull so much and it become ?

1) in all probability yes....it's their job, why call in people who aren't qualified?
2) probably a very small amount, in all likelyhood just the events which lead to MIA and unknown fates.
3) as long as the methods produced the answer does it matter?
4) let's not forget that most Spitfire pilots were flying with a squadron and the squadron pilots are all credible eye witnesses to what happens, through all of the recounted stories and biographies etc nobody ever mentioned the Spitfire as being 'particularily' weak or seeing squad mates breaking up with any regularity.