I am trying to establish the service of a Danish doctor in RAF service.

At enlistment he is evaluated by 1 CMB and classified "A4B, Fit Comm.: Medical Branch"

On 16.6.46 he is evaluated again. This time as "Not F.A or F.B on duty". Any ideas to the meaning of the latter?

At this point in time he serves with BAFO in Germany and Belgium.