It's a bleep test (or MSFT - Multi Stage Fitness Test) at OASC for P2 (ie officer and aircrew) candidates, the mile and a half on the treadmill for P3 (ie everyone else) candidates.
Pass levels, which are based on the theory that everyone's fitness will improve 10% under initial training, are:
Age MSFT 1.5-Mile Run
Male Female Male Female
<17 8 06 5 00 12:36 14:58
17-24 7 07 4 07 12:11 14:24
25-29 7 02 4 04 12:11 14:24
30-34 6 03 3 10 12:33 14:53
35-39 5 01 3 06 13:02 15:22
40-44 4 03 3 02 13:31 15:59
45-49 3 06 2 09 14:00 16:29
50-54 - - 14:34 17:06
(Please forgive the formatting; the forum won't let me use any nice tabular stuff for some reason.)