Mid-air collision claims 71 lives

A flight recorder from the Tupolev has been recovered

Mid-air collisions are mercifully rare - even in our crowded air traffic lanes, there is an awful lot of sky.

So clearly something went very seriously wrong to cause the crash of the Russian passenger jet and the Boeing cargo 'plane over Germany yesterday.

There were no survivors, though, again by great good fortune, the wreckage, which was spread over at least six square miles, did not kill anyone on the ground.

Early indications are that pilot error may have been to blame - indeed, the Russian transportation ministry has admitted as much this morning. The Russian pilot apparently repeatedly ignored air traffic controllers ordering him to descend to avoid the other 'plane.

But there is also concern that some blame may lie with the minimum permitted space between planes - six months ago, in order to ease air congestion, the minimum height clearance was reduced from 2000 to 1000 feet.

We speak to Kieran Daly, editor of internet news service Air Transport Intelligence, and ask him how it was possible for two airplanes to collide in mid-air.

Click on the link above right to hear more.