Swiss air traffic controller's telephone was not working

The lone Swiss air traffic controller on duty during last week's mid-air collision near the German-Swiss border could not contact German air traffic control because his telephone did not work, it was revealed last night.

The lone Swiss air traffic controller on duty during last week's mid-air collision near the German-Swiss border could not contact German air traffic control because his telephone did not work, it was revealed last night.

The investigators of the accident, which killed 71 people, mostly children, have found that the main telephone system was down because of maintenance work when the accident happened. German investigators said: "When trying to establish contact for co-ordination with FDH [Friedrichshafen, Germany], technical problems occurred.

"Between 23:25:43 and 23:33:11, the controller tried several times to establish contact with FDH. He was not successful." Investigators said a back-up line was apparently available.

The new revelation points the finger of blame further at the Swiss air traffic control company Skyguide, after revelations last week that another controller who was supposed to be on duty was on a break.

It was also revealed last week that an automatic collision warning system was down for maintenance at the time of the disaster.