Helios mystery deepens as tests show co-pilot still alive on impact

The investigation suffered a setback yesterday when it was found that one of the two black boxes, the cockpit voice recorder, was seriously damaged when when the plane crashed.

Initial evidence suggested that plane crashed after a malfunction in the cabin air pressure system, exposing those on board to extreme cold and lack of oxygen. But Kyriakos Pilavakis, the former chief mechanic of Helios Airways, has ruled out the possibility that decompression caused the plane to crash. He said other mistakes or technical failures must have occurred as well.

Two F-16s sent to investigate the plane after it failed to respond to air traffic control said they could see the co-pilot had collapsed but were unable to see the pilot. The pilot's body is one of three not found yet. The plane was on autopilot when it crashed.

Reports in the Greek media suggest that authorities had been minutes away from ordering the flight to be shot down. According to the daily Eleftherotypia the flight from Larnaca had been classed "renegade" after breaking off contact with air traffic controllers as it entered Greek airspace.

Early results from post-mortem examinations in Athens showed the vital organs of several passengers were working when the plane crashed, contradicting initial reports which said the bodies were frozen solid.

Police also say a widely reported text message describing freezing conditions on board was a hoax and have arrested a man in connection with the claim.