Pilatus B4 and corrosion

Hi,

does anybody know annything about Pilatus B4 having issues with
corrosion? I heard that parts of the plane are somehow corrosion
protected, but does it work even today when most of the B4s are 30
years old with 3000 hours or so? Google does not give much information
about it, so does this mean that the corrosion problem does not exist?

I have already heard that some clubs do keep their Pilatus' mostly
outside i.e not in a hangar. What is the impact of this to the glider
and what planes maintenance manual says about it and corrosion?

Regards,

Mika Koski