The case against hosing down an aeroplane

There is a reason maintenance organisations get nervous when somebody arrives at a hangar with a pressure washer.

An airframe has a great many places water can enter and very few from which it readily leaves. Control surface hinges, fastener heads, lap joints, the gap behind fairings and the recesses around inspection panels all hold moisture well past the point where the visible surface has dried. Trapped moisture against dissimilar metals is precisely the condition corrosion needs.

Encapsulated dry washing sidesteps the problem entirely. The product lifts soiling into a lubricating film that is removed with clean media; the contamination leaves on the towel rather than in the run-off. Nothing enters a seam because nothing is flowing.

The secondary benefit is practical: with no run-off there is no containment requirement, no wet hangar floor and no argument with the airfield about where the water went. We can work alongside other aircraft without inconveniencing anybody.