For all the development history of AEA (Flying Clothing) contact Dr Graham Rood at F.A.S.T (The Farnborough museum)
Farnborough Airsciences Trust homepage
The Mk1a protective & G helmet combi was replaced by the 2 & 3 series (in certain aircraft) the Mk 2 had "g" sensitve visors which were a bugger to set up & the Mk 3 took forever to fit. Then came the Mk 4 (Funny old thing)
As an aside - I remember that the Mk4 `could not be used` in the Chipmunk because it had never been formally cleared!(according to MoD PE)
