On the tapes, First Officer Richard Hazen tells a Miami ground controller: "We've got a problem, " he says in a relatively calm voice.

CNN: FAA releases ValuJet air traffic control tapes

It does not mean leaving pilots completely free to steer their own course like car drivers, but it does transfer more responsibility for plotting a route and following it to the pilot, with the ground controller keeping an eye on things.

ECONOMIST: Clearing the skies | The

The fliers are ultimately told there are no friendly forces in the area - although the ground controller admits he does not know as much about the situation as he would like, and at least one pilot spots orange panels on the British forces which should identify them as friendly.

BBC: Does 'fog of war' excuse 'friendly fire?'

The helicopters are monitored as they fly autonomously to a forward operating base, where a marine controller on the ground takes over using a portable device to direct the drop.

ECONOMIST: Autonomous helicopters

If you've ever used a modern, mid-range or above DJ controller, you'll be on familiar ground.

ENGADGET: Pioneer XDJ-Aero review: a DJ controller that loves music, hates physical formats