Indonesian and Singapore authorities have indicated that the so far inconclusive investigation into December's crash of a SilkAir Boeing 737-300 is likely to continue for at least a further six months. At the same time, legal efforts in the USA are being stepped up to force Boeing to release information on the accident, and the Indonesian investigators say they have begun to study human factors aspects.

According to an Indonesian Aircraft Accident Investigation Commission (AAIC) statement, it "-remains committed to finding out all the facts", but adds that it is "-not in a position to predict the end of the investigation".

The AAIC says its investigation teams have finished gathering air traffic control, maintenance and weather information and there is no indication that any of these was a contributing factor. This effectively narrows down the investigation to two active lines of inquiry: the aircraft's structure and systems, and human factors.

Speculation that the crash was the result of pilot suicide continues to mount, but to date there is only circumstantial evidence to support this theory. The AAIC says its human factors group will continue over the next two to three months to gather data on "the backgrounds of the flightcrew members, their professional proficiencies, careers, private lives and their actions and interactions before and during the accident flight."

US lawyers representing some of the next of kin of the 104 people killed in the 19 December crash are expressing frustration with the pace of the Indonesian-led investigation and have initiated legal action against Boeing. The manufacturer is being petitioned to release all internal documents and engineering depositions relating to the crash.

"We're entitled to that and we'll get it. They can't hide it," says David Nanz, an attorney with the New York firm Kreindler & Kreindler representing some 20 families. Boeing has 20 days to respond.

Source: Flight International