Can't look up or down while using the free look key (C) on helicopters

This has been going on for a long while, but I decided to ask about this only now.

I used to be able to press C (mouse look) and look in all directions, just like with planes and tanks. With helicopters I can only look left and right, I can’t look up or down.

Are there configs/keys that need to be adjusted? Or is it just a feature present for all players? (I fly with mouse controls, in SIM I use keyboard controls and I can look in all directions)

Anyone else with this problem?