I doubt very much that the pass level at initial selection for pilot training varies at all between the three services.
I went through Biggin Hill in 1964 and what we discovered then was that the line was drawn at exactly the same place on the list for everyone.
The big question was, "does this candidate have the potential to become a pilot within the amount of budget we are prepared to allow"
As to whether one went on to fly fighters, four engined transport or helicopters or anything at all would be decided further down the track during initial flying training. In the case of the Army, in 1964, with a couple of exceptions, everyone went rotary. I hope it hasn't changed but the Army requirement at Biggin Hill in 1964 was no less than the RAF's, it was only a measure of potential.