Frequency and duration of wetness periods on surfaces in airframes

This study reports on the wetting of sensors positioned in two diverse positions in two different air frames. The two spaces studied were a subgalley space in a commercially operated 747 and the cargo bay area of a military operated 707. The study found that in the 707 cargo, bay wetness events were relatively uncommon, with the majority of events lasting from 30 to 90 min but with some events lasting up to 600 h. In the 747 subgallery, wetness events were common, with the most frequent wetness period being 30 min (although periods of up to 270 min were observed) and the average wetness event being 50 min. The implication of such wetting intervals to the wetting and chloride ingress into intact paint films and the release of chromate into defects in paint films are discussed.