JAKARTA, Indonesia — Indonesia's top accident investigator said Wednesday that there are no indications of foul play in last month's crash of an AirAsia jetliner carrying 162 people.
AirAsia Flight 8501 plunged into the Java Sea on Dec. 28 shortly after the pilots asked to climb from 32,000 feet to 38,000 feet to avoid threatening clouds, but were denied permission because of heavy air traffic. No distress signal was received. The plane was en route from Surabaya, Indonesia's second-largest city, to Singapore.
"There is no sign of sabotage in the AirAsia crash," National Transportation Safety Committee head Tatang Kurniadi told reporters.
He said investigators have downloaded all of the data from the aircraft's cockpit voice recorder and flight data recorder and are analyzing them along with advisers from Airbus, the plane's manufacturer.
One of the committee's investigators, Nurcahyo Utomo, said Tuesday that no voices have been detected on the cockpit voice recorder other than those of the pilot and co-pilot, and no explosions were heard.
Transport Minister Ignasius Jonan told Parliament on Tuesday that radar data showed that the plane was climbing at an abnormally high rate — about 6,000 feet a minute — then dropped rapidly and disappeared.
"It is not normal to climb like that, it's very rare for commercial planes, which normally climb just 1,000 to 2,000 feet per minute," he said. "It can only be done by a fighter jet."
He did not say what caused the plane to climb so rapidly.
An excessively rapid ascent is likely to cause an airplane to go into an aerodynamic stall. In 2009, an Air France Airbus A330 disappeared over the Atlantic Ocean in bad weather while flying from Rio de Janeiro to Paris. Investigators determined from the jet's "black boxes" that it began a steep climb and then went into a stall from which the pilots were unable to recover.
Airbus spokesman Justin Dubon said Tuesday that it was too early to comment on possible similarities between the two crashes.
Kurniadi said a preliminary report on the AirAsia accident is expected to be submitted to the International Civil Aviation Organization next week, in line with a requirement that it be filed within 30 days of a crash. But he said a full analysis of what went wrong with the plane could take up to a year.
Rescuers are struggling to lift the fuselage and what appears to be the plane's cockpit from the seabed at a depth of 30 meters (100 feet). The search has been complicated by strong currents, high waves and bad weather. Only 53 bodies have been recovered so far.