Faulty Repairs Blamed for 1985 Crash That Killed 520 in Japan

Japanese government investigators said Friday that faulty repairs by the Boeing Co. were the cause of the 1985 crash of a Japan Air Lines jumbo jet in which 520 people died in history’s worst single-airplane disaster.

The Japanese Transport Ministry’s Aircraft Accident Investigation Commission also said in its official report on the tragedy that JAL’s failure to detect cracks in a bulkhead during regular maintenance inspections “had a part” in the accident.

The 556-page, two-volume report describes in detail the damage suffered by the Boeing 747-SR that caused it to crash into a mountain northwest of Tokyo.

Bulkhead Rupture

The report blamed the accident on a rupture in the rear pressure bulkhead on which it said Boeing made faulty repairs in 1978.

The report said the bulkhead, a circular wall separating the pressurized cabin from the unpressurized tail cone section, developed cracks that weakened it so it could not contain the pressurized air in the cabin.

The rapid release of pressurized air into the plane’s tail section destroyed its vertical tail fin and all four hydraulic systems--components vital to controlling the plane--the report said.

The Boeing Co., in a statement released in Tokyo, said it agreed with the report’s finding that the accident was caused by incorrect work by Boeing technicians in 1978.

Steps Are Taken

Boeing, which already has accepted full legal responsibility for the crash, said it “has taken steps to preclude the chance” of such an accident happening again.

Japan Air Lines President Susumu Yamaji said the company would “take to heart” recommendations contained in the report for improved repair and inspection procedures.