Originally Posted by
Jet_Fan
no, it's -499 because he is facing the tail. If he stops it goes back to -500. If he turns to face the cockpit while stationary it goes from -500 to +500 almost instantly.
No-it doesn't matter which way you are facing, it matters which way you have nominated as positive and negative in the reference frame you are using.
Acceleration is absolute- if his velocity changed by 1000kts in a fraction of a second, he'd be crushed by the Gs.