By Telly Nathalia JAKARTA, March 17 (Reuters) - An Indonesian passenger jet that crashed this month killing 21 people was coming in to land at a higher than normal speed, the chief investigator said on Saturday. The Garuda Indonesia aircraft with 140 people on board overshot the runway in the central Java city of Yogyakarta and burst into flames on March 7. Five Australians were among those killed. The chief crash investigator, Mardjono Siswosuwarno, said the aircraft's wing flaps failed to extend for landing and that might have been caused by the high speed. "This could be a contributing factor, but what is more important is that the plane's speed was higher than normal. Why? We don't know yet," Siswosuwarno, from the National Transport Safety Commission, told Reuters. Survivors of the crash have described how the aircraft approached the runway at a "crazy" speed. Siswosuwarno said experts in the United States had fixed the cockpit voice recorder, known as the black box, after it was badly burnt in the fire. Investigators can download the last 30 minutes of the crew's conversations, he said. Police have questioned the pilots and cabin crew. Indonesia has suffered a string of transport accidents in recent months, including an Adam Air aircraft that disappeared in January with 102 passengers and crew on board and a ferry sinking in late December in which hundreds died. Vice President Jusuf Kalla said on Friday airlines would be given warnings, suspended or shut down if an audit found they had violated safety regulations. Air travel in Indonesia, a country of more than 17,000 islands, has grown substantially since the liberalisation of the airline industry that has triggered price wars among airlines. The rapid growth has raised questions over whether safety has been compromised and if the infrastructure and personnel can cope with the huge increase. ((Writing by Ahmad Pathoni, editing by Sanjeev Miglani; ahmad.pathoni@reuters.com; Reuters Messaging; ahmad.pathoni.reuters.com@reuters.net; tel +6221 384 6364))
