Information on Japan's F-2 fighter jet ended up in the hands of a female acquaintance of a Mitsubishi Heavy Industries Ltd. employee after he sent the data to his private e-mail account in January 2002, MHI and police officials said Wednesday.
The information wasn't classified, but MHI still issued the employee and three of his superiors with stern warnings for failing to obtain permission to take technical data outside the company, the officials said.
Aichi Prefectural Police initially treated the case as a possible violation of legislation protecting Japan-U.S. secrets. It dropped this investigation, however, after determining that the data did not include defense secrets.
In mid-January 2002, an employee at MHI's Nagoya Aerospace Systems Works unit sent in-house data on plans to upgrade the F-2 to an e-mail account to study it at home.
But the e-mail ended up in the hands of a female acquaintance who also had access to the account, they said.
The woman later visited the Mie Prefectural Police department with a floppy disk containing the data, prompting Aichi Prefectural Police to launch an investigation.
MHI is the main production contractor of the F-2, which was developed jointly by Japan and the U.S.
A new jet, about 40 F-2s are to be deployed for operational tests and training by the end of March.
Scandals involving improper handling of data have hit MHI's Nagoya unit before.
In November 2001, a personal computer containing data related to simulations on fighter jet designs was stolen from the company. In April, an employee of the company lost technical material relating to fighter aircraft. after leaving it on a train.