Flight attendants trying to save a Cypriot airliner with an unconscious crew on board were locked out of the cockpit -- by the plane -- until it was too late to do anything, according to the Greek assessment of a computer simulation of the flight. More than 100 people died when the Helios Airways Boeing 737 crashed near Athens Aug. 14. The plane had some kind of pressurization problem shortly after takeoff from Cyprus on its way to Athens and the flight crew lapsed into unconsciousness. The plane continued on its programmed route to a holding pattern off the coast of Greece and flew in circles for two hours. Meanwhile, at least two flight attendants had stayed awake using portable oxygen bottles but they couldn't get through the locked, terrorist-proof cockpit door. It was only when one engine failed from fuel starvation that the computer-controlled systems aboard the plane unlocked the door. "Whoever was conscious in the cockpit had only a few minutes to save the plane," Greek Chief Investigator Akrivos Tsolakis told reporters. The third person in the cockpit, widely believed to be flight attendant Andreas Prodromou, likely didn't influence the plane's flight path. After the first engine failed, the autopilot still managed to get the plane back on its racecourse pattern until the second engine went out and the plane simply fell to earth. Tsolakis also told reporters he's looking into autopsy results that indicated both pilots had heart conditions.