Please don't take this as gospel, but it's my view from ten years or so of occasional work alongside AAIB or it's RAF equivalent.
- Experience (pilots); ATPL, preferably heavy experience, preferably some other technical qualifications, at-least 10 years operational experience. Typical entrants are in their mid 40s.
- Experience (Engineers); CEng, reasonable technical as well as management background, 5-10 years post qualification experience, some form of pilots license (higher the better), typical entrants are in their mid to late 30s.
Although all the investigative staff are called "Inspectors", a few of the Engineers do nothing but ADR work and don't visit crash sites or become involved in the nitty gritty of an investigation. Those jobs are usually specifically advertised as such.
Engineers outnumber pilots about 2:1. AAIB pays for either to stay current. PPL holders (Engineers) generally get a training and currency budget, ATPL holders will normally get seconded to an airline enough to keep genuinely current.
I don't think they've anybody employed as scientists, but the dividing line between the two professions is blurred at times.
And I've met at least one who admitted to flying an R22, but as-yet none who will fly in a microlight.
I've also yet to get anybody to admit what they get paid, but I was once told by somebody quite senior there "if AAIB wants you, they'll afford you". By which I take it they're paid more than me
Finally, I think Cranfield does an MSc in air accident investigation, which AAIB put's a lot of people through, and not a few people put themselves through with a view to that career (or a more technical and management roll in their existing employer - surely more interesting than an MBA !)
G