Jakarta's National Transportation Safety Committee said its investigators could not substantiate claims that the crash of flight MI185 had been caused by pilot suicide, a theory supported by some of the victims' families.

A separate report from the Singapore Police Force also concluded that there was no evidence that the pilot or any of the crew "had suicidal tendencies or a motive to deliberately cause the crash".

The Boeing 737-300 nose-dived from 10,000 metres into the Musi River in Sumatra on a December 19 flight from Jakarta to Singapore's Changi Airport. The aircraft disintegrated on impact, killing all on board.

Claims of a cockpit crew suicide - and the mass murder of the plane's other crew and passengers - had gained some credence as the cockpit voice recorder and the flight data recorder had stopped working just minutes before the plane went into its final descent.

There had been speculation that Captain Tsu Way Ming, the pilot, or Duncan Ward, the co-pilot, may have switched them off. The Singapore report said that in an incident six months before the crash, Tsu had disabled a cockpit voice recorder before a flight to Jakarta. The action led to Tsu being demoted, Singapore police said, but concluded that neither the disabling nor the disciplinary move had contributed to the subsequent crash.

Police also discounted any connection between the SilkAir crash and a crash in 1979 that killed three of Tsu's colleagues in the Royal Singapore Air Force. The SilkAir disaster occurred on the anniversary of that 1979 crash.

Safety committee chairman Professor Oetarjo Diran recommended that the design of both cockpit voice and flight data recorders be reviewed "to identify latent factors associated with stoppage of recorders in flight".

He also recommended that aircraft and equipment manufacturers include recording of actual displays as observed by pilots - but stopped short of endorsing the installation of video cameras in cockpits. The Singapore Government said last night that it accepted the committee's report and hoped that it would provide "closure for the families concerned".

US officials, who aided the Indonesian probe, were unavailable for comment, although Professor Diran said that they had backed consideration of pilot suicide as a possible cause. "This was a possibility that the investigation team explored extensively," Professor Diran said.

The committee summary said that the plane, operated by the Singapore Airlines subsidiary, was flying in light winds and scattered cloud at the time of the crash.

It said that recordings from the cockpit voice recorder stopped at 9.05am and recordings from the flight data recorder stopped six minutes later. At 9.12am the plane started its near-vertical descent, registering on air traffic control radar screens at 5,900 metres 32 seconds later. Professor Diran said there were no indications as to why the aircraft started its descent, nor why the recorders stopped working.

Before the crash, SilkAir and parent SIA had had one of the best safety records in the industry. In October, Singapore Airlines' flight SQ006 crashed while attempting to take off from a partially closed runway at Taiwan's Chiang Kai-shek International Airport, killing 83.

Jake Lloyd-Smith the Post's Singapore correspondent.