Andrzej Jeziorski/SINGAPORE

After 15 months of investigations into the December 1997 crash of a Silk Air Boeing 737-300, Indonesian officials have published a crash report which reveals little more than was known a year ago.

Representatives of the families of 57 of the 104 people who died on flight MI 185, which crashed into the Musi river in South Sumatra on 19 December 1997, are planning legal proceedings against Silk Air parent Singapore Airlines (SIA). The group is pushing for legal recognition, and is planning to petition Singaporean Prime Minister Goh Chok Tong and Indonesian President Bucharuddin Habibie to press for the release of more investigation findings.

Pilot suicide is one of two accident theories. The second is an uncommanded rudder deflection, which is believed to have caused the 737 crashes in Pittsburgh in 1994 and Colorado Springs in 1991.

The Indonesian Air Accident Investigation Commission's (AAIC) interim report says: "The investigation so far found no indications that air traffic control, weather, maintenance, terrorist acts or hazardous materials were factors contributing to the accident." The investigation is focusing on potential aircraft or system anomalies that could have precipitated a loss of control, and human factor aspects that could have contributed to the descent from the cruise altitude.

The aircraft was cruising at 35,000ft (10,600m) when it entered its fatal dive. There was no distress call and the flight data and cockpit voice recorders failed or were switched off before the descent.

The background of the pilot Tsu Way Ming has come under intense scrutiny, with questions arising about safety incidents he was involved in while serving in the Singaporean air force, as well as his demotion before the accident. It has also been alleged that he was in financial difficulty and had taken out a large life insurance policy shortly before the crash.

According to Oetarjio Diran, chairman of the AAIC, Singaporean banking laws prevent access to Tsu's financial records without a court order. Diran adds that he has no intention of pursuing a court order, because this is not a criminal investigation.

Source: Flight International