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...
Badass in a Sig #3 - Genos (One Punch Man)
Cybernetic, respectful yet somewhat impulsive and crazy cool in battle. Upgrading his systems to do even more damage than ever before...and he just has the most badass look, seriously. One of the best fire-based characters I've seen.