[rafcommands]

Time, I think, that you did a little background research into RAF training. Try reading "Right of the Line" for an excellent overview of RAF matters.

As I have said the aircrew trade of observer did not require a specific rank or did any of the other aircrew positions so his commission has nothing to do with his trade and vice versa.

The best way to identify when he joined the squadron is to examine the ORB. You can do this either personally, order photocopies from a distance or use a researcher to examine the archives on your behalf.

Regards
Ross