The near-intercept of a U.S. military drone—mistaken for an unidentified flying object near the Paju armistice frontline on July 30 during a combined exercise—stemmed from a communication error between South Korean and U.S. military working-level personnel, officials said.

According to the findings, the U.S. military notified flight plans only via text message the day before the exercise, and a working-level officer assigned to the Army's 1st Corps failed to disseminate or report the plan to superiors, triggering the commotion.

A Joint Chiefs of Staff official told reporters today (Aug. 3) that an inspection by the JCS readiness inspection team revealed these details.

"On the South Korean military's side, the causes identified were the failure of the reporting system along the chain of command to function, and the non-compliance with official special-use airspace flight authorization procedures due to convention," the JCS official said.

"This case confirms the necessity of complying with airspace control procedures between South Korea and the U.S. in accordance with regulations," the official added, noting that "we plan to supplement the airspace control coordination system based on close communication between South Korea and the U.S. going forward."

According to the investigation, the U.S. side notified the 1st Corps working-level officer of the drone flight plan via mobile text message on July 29, the day before the exercise.

The officer reportedly replied to the U.S. side that there were "no restrictions" and did not report or disseminate the fact to superiors or higher headquarters.

It is understood the officer assumed the matter notified by the U.S. involved drone flights below a certain altitude and judged it to be a matter of discretion within the 1st Corps.

However, the U.S. drone flew higher than expected. As a result, South Korean military authorities spotted the U.S. Marine Corps drone participating in the exercise, mistook it for an "unidentified flying object," issued "Durumi," an air defense operation posture for responding to enemy drones, and even prepared to intercept it.

While the primary fault lies with the South Korean working-level officer who omitted the notification of the drone flight plan despite receiving it, investigators also found shortcomings in the process by which the U.S. military notified the South Korean military.

To obtain special-use airspace flight authorization, flight plans must be notified via official documents a certain period in advance and approved by the Air Force Operations Command or Ground Operations Command. Instead, this was replaced by text messages between working-level personnel the day before the exercise.

However, it was found that communication between South Korean and U.S. working-level personnel has customarily been handled this way.

The military explained that it will supplement the airspace control coordination system between South Korea and the U.S. moving forward.

Meanwhile, the Ministry of National Defense announced today that it has relieved the commander of the 1st Corps—where the U.S. drone misidentification incident occurred—of his duties and will investigate the related matter.

(Photo: Joint Press Corps, Yonhap News)