The humidity at 98% on the tarmac is not the problem as the airframe will be at the same temperature and will not cause condensation. At altitude where the outside temperature is well below zero, moisture will condense on colder surfaces forming liquid water around and possibly in components that are not completely sealed and/or insulated from the colder surfaces.
Last edited by ZimmerFly; 22nd Jul 2013 at 06:49.