Seven Air Self-Defense Force jets were apparently sabotaged between April and early July while undergoing routine repairs at a Mitsubishi Heavy Industries Ltd. plant, police said Thursday.
Six F-4EJ Kai fighters and one RF-4E reconnaissance jet were damaged, including severed wiring and bent engine spark devices. The damage was found in 11 locations on the planes while they were in for repairs at Mitsubishi Heavy's Komaki Minami factory in Toyoyama, Aichi Prefecture.
The company alerted Aichi Prefectural Police of the damage on July 22.
Police said they believe an insider was behind the "malicious damage" because access to the factory is strictly controlled. Some 120 of the 1,300 employees at the plant are involved in warplane repairs.
The sabotage has prompted the ASDF to begin special checks on all 14 F-4EJs, which employ new radar and fire-control systems, and one RF-4E that recently underwent repairs at the plant. The planes had been returned to their bases after the regular repairs.
Mitsubishi Heavy said the damage posed no safety problems because any abnormalities could be discovered during preflight checks.
Wiring near the cockpits was severed with a sharp instrument in eight cases, and three spark devices were bent.
The Tokyo Shimbun reported Thursday that the sabotage discovery prompted the ASDF to ground 15 planes and to order a special inspection. Some of the 15 planes had undergone routine repairs at the plant this year before the damage was discovered.
