Jet crash controller 'overburdened'

Relatives have been paying their respects at the site

Investigators have said that a Swiss air traffic controller was left alone and overwhelmed with work as two planes ploughed into each other over southern Germany, killing all 71 people on board.

The German Federal Agency for Air Accidents said Zurich ground control - which was in charge of the planes at the time - warned the pilot of a Russian airliner to change course just 44 seconds before impact.

Criminal proceedings have begun into whether negligence was responsible for the crash.

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I hope the airlines learn from it and reduce the traffic in the air

Harald, Germany

Relatives of the victims have flown to Lake Konstanz from the Russian republic of Bashkortostan to mourn their dead at the site of the crash.

Families carried wreaths and pictures of the 52 children who died. Many broke down in tears as they laid flowers or took photographs of the area, where wreckage from the aircraft remains strewn across fields.

	:	Mid-air collision
How the crash happened

"We're taking soil from the site of the catastrophe back to Bashkortostan. It is stained with the blood of our children," said one father.

They brought with them clothes and toothbrushes to help with DNA identification.

So far only two of the 68 bodies recovered have been identified.

Countdown to crash

Attempts to piece together what caused the Russian Tupolev to collide with a Boeing cargo jet have been hindered by damage to the black boxes recovered from the wreckage.

Moments before crash

44 secs before: Ground control warning to Russian pilot

30 secs before: Russian pilot descends on second warning

14 secs before: Boeing warning system informs ground control of descent

Russian experts have been called in to examine an extra flight recorder from the Russian plane which was recovered on Thursday.

However, careful examination of radio transmissions in the moments leading up to the collision has shown that Swiss ground control gave just 44 seconds' warning.

Peter Schlegel, head of the German investigation, said 90 seconds would have been needed to avert disaster.

Instead, the Russian plane only began to descend on a second warning, issued 30 seconds before the crash.

An automatic collision-warning system onboard the Boeing is understood to have informed ground control 14 seconds before impact, that it was sending the cargo plane downwards and into - instead of away from - the Russian jet, investigators said.

Legal proceedings

The Swiss air traffic control company, Skyguide, has admitted that its own ground-based collision warning system had been switched off for routine maintenance at the time of the crash and that one of two air traffic controllers had gone on a break.

	Tupolev 154 flying from Moscow to Barcelona Boeing 757 flying from Bergamo to Brussels Collision happened on 1 July at 2130 GMT. All on board both planes lost What went wrong?

The German investigation says the staff member left alone was trying to monitor five planes on two screens at the time of the crash.

One of them was landing at a nearby airport and required a lot of the air traffic controller's attention.

Prosecutors in Germany and Switzerland have begun legal proceedings to determine whether negligence was responsible for the crash. They are both expected to question Skyguide.

The disaster has prompted German Transport Minister Kurt Bodewig to renew calls for an integrated European Union air traffic control system.

The European Commission has already announced plans for an integrated system, but these are opposed by trade unions who fear job losses and say safety standards could be compromised.