ZURICH/LONDON, 4 July — Swiss air traffic controllers said yesterday that an automatic warning system had been switched off for maintenance when two jets crashed into each other over Germany, killing 71 people.
Skyguide, the private agency responsible for safety in the skies, said it was questioning why the air traffic controller on duty during the crash did not intervene earlier to warn the Russian pilot of the risk of collision, and why the Russian pilot only reacted after a second warning.
Skyguide spokesman Roger Gaberell said ground control’s “short-term conflict alert” system was on routine “fallback mode” while maintenance was being carried out at the time the Russian passenger jet and DHL Boeing cargo plane collided shortly before midnight Monday.
The device was undergoing routine software maintenance at a time when Swiss air space was relatively clear of aircraft. There were only five planes in the sector whereas the normal workload is between 20 and 40 aircraft.
However at the time of the disaster only one controller was on duty. Regulations stipulate that when the “Short Term Conflict Alert” (STCA) device is not operational there should be two controllers in the tower.
However a second member of staff, who will now be the subject of a disciplinary process, had taken an unauthorized break.
Controllers “see” aircraft on their screens in the form of a blip surrounded by data giving key information such as the flight number and height of the aircraft.
When STCA detects that planes are heading for a potentially dangerous situation, the data flashes and a line appears between the two aircraft concerned. The controller can then order the pilots to take avoiding action. Gaberell stressed that the air traffic controller on duty had alerted the Russian pilot 50 seconds before the incident, which he said was within international minimum standards.
Meanwhile, mosques in Bashkortostan offered prayers yesterday for victims of the air crash, 45 of them local children. The tragedy has left the inhabitants of this predominantly Muslim Russian republic in shock. (The Independent)
