Really if I remember correctly from the videos, you only need to hit him with a few shots from the Grenade Launcher (I hope you have BOW gas rounds) and then you hit the button, that'll be enough to send him out of the plane. I think I only used three shots of BOW gas rounds and I was able to beat him. I know, old thread ;>_> you're probably long passed this part...
What do you see, when you look at me? That I'm angry? That I could hurt you? It must be my eyes...creeping along your body, you can feel the death waiting for you in my eyes.