The Defense Ministry has determined that a succession of human errors was responsible for one of two false alarms stating that North Korea had launched a rocket last month, a day before the missile was actually fired, a copy of the ministry report obtained Thursday shows.
The report, concerning that warning issued shortly after noon on April 4, said even top Self-Defense Forces brass failed to corroborate the data from the U.S. early warning satellite — which Japan counts as its best source of launch information — before it got out, and called for more thorough verification of such alerts.
The erroneous data were quickly sent to local governments and media organizations across the country, deeply embarrassing the government and confusing the public, which was told throughout the day to be on high alert for falling debris, even though there was nothing that could realistically be done to avoid it and no other advice was given.
The April 4 fiasco began a little more than an hour into the launch time frame disclosed by North Korea, which said it was putting a satellite into orbit and that the rocket would fly over Tohoku.
At 12:16 p.m., the Air Self-Defense Force’s Air Defense Operations Group notified the Air Defense Command of a trace picked up by surveillance radar in Asahi, Chiba Prefecture, the report said.
The notification was accompanied by the phrase “spark information” — a code used to refer to the detection of a ballistic missile.
But someone at Air Defense Command misinterpreted the missive as a finding by a U.S. early warning satellite and announced it as “SEW received,” meaning the information came from the U.S. satellite, the report said.
Another person at Air Defense Command then relayed the information to the SDF’s Central Command Post at the Defense Ministry, where a managerial-level official conveyed it to another official at the prime minister’s office through a voice monitoring device using the word “launch,” the report said.
The prime minister’s office then sent out the information nationwide.
At 12:17 p.m., it dawned on Central Command Post that no launch information had been received from the U.S. satellite, the report said. The radar in Chiba had also lost the trace by then.
The report concluded that the error was caused by miscommunication within the Air Defense Command and failure at both the Air Defense Command and Central Command Post to verify the information.