The Kopp-Etchells Effect

An excellent article by Michael Yon on the naming of the effect caused by helicopter blades spinning against dust:

"Basically it is a result of static electricity created by friction as materials of dissimilar material strike against each other. In this case titanium/nickel blades moving through the air and dust. It occurs on the ground as well, but you don't usually see it as much unless the aircraft is landing or taking off. The most common time is when fuel is being pumped. When large tankers are being fueled they must be grounded to prevent static electricity from discharging and creating explosions."

The Kopp-Etchells Effect