A Japanese court has rejected a plea for the release of black box data for the 1985 Japan Airlines jumbo jet crash.

The Tokyo District Court on Thursday turned down the demand by the widow of one of the victims for JAL to disclose the raw data on the voice and flight recorders retrieved from the plane.

The Boeing 747 crashed into a mountain ridge in Gunma Prefecture, north of Tokyo, on August 12, 1985. Only four of the 524 people on board survived.

The plaintiff says the records of the situation at the time of the accident contain personal information related to her husband just before his death. She says bereaved family members have the right to know.

In the ruling, Presiding Judge Kamoto Makiko said the data did not contain personal information as defined under the law. The ruling said there are no legal grounds for approving disclosure.

The judge said it is natural for bereaved relatives to want to get information on an accident. She said there are cases in which transport companies are obliged to provide information to passengers and bereaved families based on a transportation contract.

But she said that in this case, an investigation panel's report on the accident had made public the contents of the recorders. She also said the plaintiff had reached a settlement in a damages suit against JAL.

The judge said even if the carrier had an obligation to provide information, it has already expired.