The near-miss incident last month where a U.S. military drone participating in a joint exercise near the Paju armistice line was mistaken for an unidentified flying object and nearly intercepted stemmed from a communication error between working-level officials of the South Korea-U.S. military authorities, it was revealed.

The commotion occurred because the U.S. military notified its flight plan solely via a text message the day before the exercise, and a working-level officer assigned to the Army's 1st Corps failed to disseminate or report this plan to superiors.

An official from the Joint Chiefs of Staff (JCS) stated today (Aug 3) that an inspection of the military's combat readiness posture by the JCS revealed these findings.

The JCS official explained, "The causes identified on the South Korean military's side are that the reporting system according to the chain of command did not operate, and that official procedures for special-use airspace flight approval had not been observed in accordance with practice."

The official added, "This is a case that confirms the necessity of complying with airspace control procedures between South Korea and the U.S. according to regulations," and noted, "Moving forward, we plan to supplement the airspace control coordination work system based on close communication between South Korea and the U.S."

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

This working-level 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-level units.

It is understood that the officer considered the matter notified by the U.S. side to be a drone flight below a certain altitude and judged it to be within the discretion of the 1st Corps.

However, the U.S. drone flew higher than expected, causing the South Korean military authorities to spot the U.S. Marine Corps drone during the exercise, mistake it for an unidentified flying object, issue "Durumi," an air defense operation posture responding to enemy drones, and even prepare for interception.

While the primary fault lies with the South Korean military working-level officer who omitted the fact despite being notified of the drone flight plan, it was also found that there were shortcomings in the process by which the U.S. military notified the South Korean military of the drone flight plan.

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

However, it was found that such communication has customarily taken place between South Korean and U.S. working-level officials in the past.

The military stated that it will improve the airspace control coordination work system between South Korea and the U.S. moving forward.

The Ministry of National Defense announced today that it will relieve the commander of the 1st Corps—where the confusion over mistaking the U.S. military drone occurred—of his duties and investigate the related matter.