Ignasius Jonan told the Indonesian parliament that radar data showed the Airbus A320 was climbing at about 6,000ft (1.82km) a minute before it disappeared on December. 28. “It is not normal to climb like that, it’s very rare for commercial planes, which normally climb just 1,000 to 2,000ft (305m to 610m) per minute,” he said. “It can only be done by a fighter jet.” He said the plane then plunged and disappeared from radar.
Mr Jonan did not say what caused the plane to climb so rapidly. In their last contact with air-traffic controllers, the pilots of AirAsia Flight 8501 asked to climb from 32,000ft (9.7km) to 38,000ft (11.5km) to avoid threatening clouds, but were denied permission because of heavy air traffic. Four minutes later, the plane disappeared. No distress signal was received.
An excessively rapid ascent is likely to cause an plane to go into an aerodynamic stall. In 2009, an Air France Airbus A330 disappeared over the Atlantic Ocean while flying from Rio de Janeiro to Paris. Investigators were able to determine from the jet’s black boxes that the plane began a steep climb and then went into a stall from which the pilots were unable to recover.