The wreckage of the crashed Mu5210 flight. Flight Mu5210 from Baotou to Shanghai, east China, fell to the ground about a dozen seconds after it took off from Baotou airport at 8:20 a.m. (0020 GMT) on Nov. 21, 2004, killing all 47 passengers and six crew members on board.[newsphoto]

Investigators have ruled out the possibility of sabotage in the airliner crash that killed 54 people in North China on Sunday.

According to investigators, there is no evidence so far suggesting man-made destruction in the incident, said Xu Li, a senior official with General Administration of Civil Aviation of China (CAAC), the nation's civil aviation watchdog.

Xu made the remarks at a conference on the air tragedy Monday in Baotou of North China's Inner Mongolia Autonomous Region, where the crash occurred.

Efforts are still under way to determine the cause of the accident, he said.

The 50-seat regional CRJ-200 jet, carrying 47 passengers and six crew members, fell on Sunday morning shortly after it took off from Baotou. One man on the ground was also killed. The remains of the victims have been found.

Compensation for the victims is in progress. Twenty-five of the 47 victims were confirmed to have purchased 26 insurance policies before boarding the doomed flight, with each premium worth 400,000 yuan (US$ 48,000), Zhi Pengfei, director of the Insurance Supervision Bureau of the autonomous region, told Xinhua. The first sum of compensation has been paid to the families of a victim.

Experts from the rescue and salvage bureau at the Ministry of Communications have arrived at the accident site to help in a search for the so-called black box, the Xinhua News Agency reported.

But some say the flight data recorder will provide little in the way of helping to determine the cause of the crash since it occurred only 12 seconds after take off.

The incident may be a result of mechanical failure or faulty operational technique, said an aviation expert from the civil aviation cadres' college, speaking on the condition of anonymity.

According to a statement from Bombardier Aerospace, the airplane manufacturer, an expert team has been sent to China to help in the accident investigation, Xinhua reported.

Supplied by Canadian-based Bombardier Aerospace and owned by China Eastern Airlines, it was scheduled to be bound for East China's metropolis Shanghai.

While working to handle the plane crash, CAAC urged its aviation sectors to intensify safety checks Monday to ensure safe flights.

The administration had dispatched investigative teams across the country to carry out checks into all CRJ-200 airliners in service, Xu said.

All CRJ-200 flights will be suspended during the check out period, he said.

Airlines must strengthen flying skills and aircraft maintenance to ensure safer flights, an urgent notice released by the CAAC said Monday.

Airports must intensify security check measures to tighten management of restricted areas, the notice said.

Air control departments have also been asked to pay additional attention to safety supervision to ensure air traffic safety.