Fuel dumped by an airplane breaks up into small droplets in the turbulent slipstream and quickly evaporates before it falls very far - and, being distributed fr

Fuel dumped by an airplane breaks up into small droplets in the turbulent slipstream and quickly evaporates before it falls very far - and, being distributed from a fast-moving airplane, leaves only a thin and quickly-dissipating slick on the surface. If the goal was, as you suggest, to get rid of any trace of the fuel, one would simply not do it close to the surface! As it happens, I believe the Inmarsat events and radar intercepts indicate that the airplane was flying at a normal cruising altitude, and the the claim that it flew this pattern puts it at 36,000ft. The simplest way to crash without leaving a fuel slick is to fly until fuel exhaustion. Spending 22 minutes in a holding pattern would put off estimates of how far the airplane could have gone on its fuel load (as would dumping fuel en-route), but I have no reason for thinking this was a motivation of the person then in control of the aircraft.