As relatives and forensics experts yesterday began the painful task of identifying the remains of 121 people killed in Greece’s worst air disaster, investigators pondered what had caused the Cypriot passenger jet to smash into a wooded hillside just five miles (8 kms) from Athens’s airport on Sunday. The plane had flown across the Mediterranean from Cyprus, apparently with no one in control, before crashing into one of the few unpopulated areas near the Greek capital. The tail section (AFP photo) of the Boeing 737 was one of the few bits recognizable as part of an aircraft. The investigation focused on what had caused the pilot and co-pilot of Helios Airways Flight ZU522 from Larnaca to Prague via Athens to lose control of the plane so suddenly that they could not alert air traffic control. Apparently on autopilot, the plane kept flying without responding to air-traffic controllers. Two Greek F-16s that were sent up to investigate reported that the co-pilot was slumped over the controls, apparently wearing an oxygen mask, while the pilot was not visible. They also reported two unidentified people apparently trying to regain control of the plane, according to government spokesman Theodoros Roussopoulos. It was not clear precisely when this dramatic effort was made during the jetfighters’ helpless escort of the doomed plane between 11.20 a.m. and the crash at 12.05 p.m. Reports yesterday said the body of a woman flight attendant was found in the cockpit’s wreckage. Athens coroner Philippos Koutsaftis said his main hypothesis was asphyxiation, suggesting a lack of oxygen, but he warned that nothing could be ruled out. This would suggest that most – if not all – the people aboard had died before the crash. But aviation experts said crew members should have had a separate oxygen supply, which would have allowed them to retain control of the plane. Sudden decompression at high altitude would have still allowed the pilots to keep functioning – as long as they had oxygen. The aircraft’s voice and flight data recorders were recovered from the hillside near Grammatiko, after firefighters extinguished a blaze caused by the crash. They will be sent to Paris for analysis. Cyprus declared three days of official mourning. Greece will observe a day of mourning today. Of the 121 aboard the Helios Airways Boeing 737, 104 were Cypriots (including five crew members), 16 were Greek and Cypriot residents of Greece, and the pilot was German.