BOOM! That's what happened, a RPG get launched and hit the helicopter, throwing you out, but luckily the safety rope that connected with your vest could save you, but now you're in upside-down position, avoiding the vehicles passing by

"Sergeant?! Dammit, he's gone!" Nikolai says while trying to control the helicopter so they don't crash

"IM NOT DEAD, NIK. IM HANGING ON THE BLOODY ROPE!" You shouts, while shooting the enemy vehicles with your pistol