Investigators analyzing the crash last month of a China Airlines flight said Tuesday that the flight data and cockpit voice recorders, together with autopsies on the victims and an examination of the wreckage, showed no evidence of an explosion or pilot error.

The findings indicate that something probably went wrong inside the aircraft, a Boeing 747-200, said Kay Yong, the managing director of the Aviation Safety Council, the agency here that is conducting the investigation.

Investigators are paying special attention to whether structural failure or engine problems might have caused the plane to break into four pieces in mid-flight. The crash of the Hong Kong-bound flight into the Taiwan Strait on May 25 killed all 225 people aboard.

Searchers have recovered 162 bodies and 15 percent of the wreckage, including part of the cockpit, and have found no signs of burns or of any explosives or gunshots, Mr. Yong said.

But China Airlines, which is struggling to preserve its commercial viability after nine fatal crashes since 1970, said that it was too soon to rule out "external forces," as opposed to mechanical failure, as a cause of the crash.

Roger Ham, a company spokesman, said that only a small part of Pan Am Flight 103, which was destroyed by a bomb over Lockerbie, Scotland, had been burned. "You have to recover all the wreckage to see what part is attacked or exploded," he said, while declining to comment on what China Airlines thinks caused the crash.

There was also early speculation that the aircraft's fuel tank might have exploded. A fuel tank explosion was implicated in the crash of Trans World Airlines Flight 800, a Boeing 747-131, into the Atlantic Ocean off Long Island shortly after takeoff on July 17, 1996. But Mr. Yong said today that there was no evidence this happened to the China Airlines flight.

On Monday the airline offered to pay $372,000 to each of the families of the people who died. But the offer, made by airline officials to a gathering of more than 300 relatives of crash victims, drew a rancorous reception from some, who said the company should pay $588,000 per victim, or twice what it paid after a fatal crash in 1998, and called for punitive damages.

Some families of crash victims have accused to airline, and to a lesser extent Boeing, of ducking responsibility for the crash. Lee Ham, a crash victim's son, said that China Airlines was to blame for having kept a 23-year-old plane in service too long. The aircraft crashed on its last flight before it was to be sold to a small carrier in Thailand.

Boeing declined to comment on today's statements by investigators. But Ivy Takahashi, a company spokeswoman, said that the plane that crashed had been on 21,398 flights, below the average of 23,000 flights for all Boeing 747-200s in service.

The breakup of China Airlines Flight 611 has drawn international attention because it comes at a time of increasing concern over how long older jets can remain airworthy. Some research has suggested that metal fatigue may be a particular problem in planes that are used regularly in very warm, humid places like Taipei and Hong Kong. But Boeing maintains that with proper maintenance, aircraft aging should not be a problem.

The flight data recorder from Flight 611 shows that the plane began gaining altitude at a significantly faster rate in the 27 seconds before the plane broke apart, although the extra gain in altitude was well within the plane's design limits, Mr. Yong said at a news conference here today. The plane was supposed to be leveling off then as it approached its cruising altitude of 35,000 feet.

No one in the three-member flight crew said anything to indicate an awareness of the extra lift, Mr. Yong said. The autopilot had been engaged earlier in the flight, and there is no evidence that it was turned off before the plane came apart, he added.

Shortly before the breakup, one of the aircraft's four engines began providing slightly less thrust. By coincidence, the same engine is the only one that has been recovered so far from the sea floor.

Phil Tai, the investigator overseeing the recovery of wreckage, said that the engine was intact except for a tiny piece that was missing from the nose cone. Many parts of the engine had been split along the side, apparently when they hit the water after falling more than five miles.

On Sunday, Mr. Yong had separately announced that the cockpit voice recorder had picked up a dozen faint, mysterious sounds in the 13 minutes before the plane came apart. A computer disk with the sounds has been sent to the United States for further analysis, which will take at least a week, Mr. Yong said today.

(China Daily June 26, 2002)