Currently it's impossible to aim at 90° (vertically) in elevation and in depression. it provocate dead angle when trying to engage targets located above or below the player position.
for example if you try to engage an helicopter auto hoovering just above you, you can't, because ingame the elevation and depression angle are limited to +60°/-60°.
In real life there is no such limitation. you are able to fire with any angle.
the stances positions that should allow +/-90° aiming angle are :
standing up
crouching
sitting down.
the current prone position doesn't allow positive shooting at more than 45°. but if BIS could add the posibility to turn on the back while being prone we could engage target located above us. {F21555} {F21556}
