In some cases the direct sunlight is annoying for the pilot.
In real life, i suppose, the pilot helmets are equipped with sun visor that can be raised and lowered at will of the pilot.

In some cases it would be useful in the game.

Maybe not need to set a default button, if necessary, will be the player to choose the most convenient button to raise and lower the visor. {F19181} {F19182} {F19183}