It's on pages 71, 78 and 83.
Fast vehicles can move at combat speed (0"-6") and fire all weapons at full BS and move at cruising speed (6"-12") can fire 2 weapons at full BS and others as snap shots.
Ravagers have aerial assault, so they can fire all weapons at full BS, if they move at cruising speed and flyers can fire four weapons at full BS.
Passengers count as having moved, when the vehicle moved at combat speed (0"-6"), so only snap shots for heavy weapons.
If the vehicle moves a cruising speed (6"-12") then passengers can only fire snap shots, regardless of weapons.
Neither vehicles nor passengers can fire if the vehicle goes flat out.
I must rule with eye and claw — as the hawk among lesser birds.