Japan Releases Audio of Naval Incident with South Korea

Credit: Japan Ministry of Defense
Credit: Japan Ministry of Defense

Published Jan 22, 2019 7:12 PM by The Maritime Executive

Japan's Ministry of Defense (MOD) has released audio that it claims confirms that a South Korean (ROK) destroyer allegedly trained its fire-control radar on a Japanese patrol plane in December 2018. 

Fire-control radars are directed at its target immediately before firing. According to CUES (Code for Unplanned Encounters at Sea), a code adopted in 2014 by navies from 21 countries including Japan and the ROK, aiming fire control radars is considered a simulation of attack and is stipulated as an action a commander might avoid.

The fire-control radar detection sound is available here. The search radar detection sound is available here. Note: Parts of the sound are processed for information security.

The Ministry had previously released video footage of the incident which occurred at around 3 p.m. (JST) on December 20, 2018, within Japan's Exclusive Economic Zone. A fixed-wing patrol aircraft (P-1) belonging to the Fleet Air Wing 4 of the Maritime Self-Defense Force (MSDF) was allegedly irradiated by a fire-control radar from a South Korean Navy destroyer off the coast of the Noto Peninsula, Japan. The plane was observing the destroyer and an ROK patrol and rescue vessel. 

Upon analysis of the frequency, intensity, waveform, etc. of the radar waves, Japan's MOD says it has confirmed that the P-1 was continuously irradiated for a certain period, multiple times by the fire-control radar (STIR-180) of the ROK destroyer that was being photographed. The STIR-180 was not mounted on the patrol and rescue vessel that was nearby at the time, and the MOD says the fact the ROK destroyer directed its radar is clear from the video footage.

South Korea has denied that the incident occurred and has demanded that Japan "stop distorting facts" and "apologize for conducting a threateningly low-altitude flight."

Japan's MOD says it is necessary that a comprehensive assessment is made using the ROK's data regarding the detailed capability of the fire-control radar equipped on the ROK destroyer - as a matter of reciprocity. The MOD requested this on January 14, but the proposal was rejected. On January 15, Japan claims that a spokesperson from ROK's Ministry of National Defense denounced the MOD's proposals as "extremely rude."

 Japan's MOD has offered the explanations below for the incident:

(1) Regarding the flight by the MSDF P-1

The ROK claims that the MSDF P-1 conducted "a threateningly low-altitude flight" in the vicinity of a ROK destroyer conducting a "humanitarian rescue mission", and is demanding an apology.

There is no international law that directly regulates the minimum safety altitude for military aircrafts, but in order to ensure safety, the MSDF operates under Japan's domestic law that conforms to the Convention on International Civil Aviation, and did not conduct any flight that may threaten the ROK destroyer. It is our understanding that normal operations by the U.S. Forces and NATO are carried out under similar standards.

In fact, as apparent from the footage released by the MOD on December 28 and the MSDF P-1's track chart, the MSDF P-1 maintained a sufficiently safe altitude (approx. 150m) and distance (approx. 500m) from the ROK destroyer even at its closest, and did not conduct flight that may interrupt the ROK destroyer's activities. In addition, because the ROK destroyer did not respond to the P-1's call outs by radio communication, the MSDF P-1 was unable to recognize that the ROK was conducting rescue activities.

No evidence to support the ROK's claim can be found in the 10-second footage released by the ROK of what seems to be the MSDF P-1 patrol aircraft filmed from the ROK patrol and rescue vessel, and no other objective evidence to support the ROK's claim that the MSDF P-1 conducted "a threateningly low-altitude flight" has been presented.

Even prior to this incident, the MSDF has conducted similar flights and has photographed vessels when observing not only Korean but other foreign vessels during its intelligence collection and warning and surveillance activities. Since April 2018, the MSDF has photographed the exact same ROK destroyer "Gwanggaeto-daewang" destroyer three times (April 27, April 28 and August 23), but the ROK did not express its concern regarding these flights.

The MOD had requested additional objective evidence to support the ROK's claim at the working-level meetings, but the ROK has failed to provide such evidence, and has repeatedly responded with claims that entirely lack in objectivity, such as "if the subject of the threat feels threatened, it is then a threat."

For these reasons, the MOD has concluded that the ROK's claim lacks both persuasiveness and support from factual evidence, and was made to dilute other important issues regarding the fire-control radar incident.

(2) Regarding communication conditions

In general, naval vessel crew will call out by radio communication when feeling threat, but the ROK destroyer, despite seeing the MSDF P-1 aircraft's flight as a problem, had not taken measures by any means to call out to the P-1 about its concern.

In addition, after being irradiated by the fire-control radar, the MSDF P-1 patrol aircraft had called out using three frequencies in international VHF (156.8MHz) and emergency frequencies (121.5MHz and 243MHz), but there was no response at all from the ROK destroyer.

Regarding this issue, the ROK has explained that the destroyer did not respond because the communication condition on site was poor, and they were unable to catch most of the call outs from the aircraft and thought they heard the phrase "KOREA COAST." In addition, the ROK also explained that the communication equipment on board was not tuned to be able to hear one of the three frequencies.

However, the weather conditions on site that day was sunny with very few clouds, and communication conditions were extremely good. In addition, the MSDF P-1 used the same radio communication equipment (it has been confirmed that this equipment was operating normally before, during, and after flight) used to call out to the ROK destroyer to communicate with on-land stations in Saitama Prefecture, and it has also been confirmed that an ASDF training aircraft flying at a location approximately 240 km away from the P-1 heard the call out made by the P-1 to the ROK destroyer.

It is improbable under normal circumstances that radio communication could not be clearly received in such good communication conditions, and in the footage released by the ROK, the call out from the P-1 to the ROK destroyer can be clearly heard ("KOREAN SOUTH NAVAL SHIP, HULL NUMBER 971, THIS IS JAPAN NAVY.") Considering this point, at the working-level meeting on January 14, the ROK explained for the first time that, upon repeated inspection of the call out from the MSDF P-1 patrol aircraft, it was later found that the communication personnel had misheard the radio communication. Prior to this, the ROK had never disclosed this information in its press conferences and had only explained that the destroyer did not respond because they heard "KOREA COAST."

The MOD strongly calls for the ROK to take measures to improve communication between Japan-ROK defense authorities on site, such as conducting appropriate communication to JSDF aircrafts, improving conditions of communication reception, and conducting education/training to communication personnel, so that such incidents never recur.

South Korea's MOD has offered the explanation below for the incident:

According to the video, the Japanese patrol aircraft approached the destroyer within 500 meters, and flew approximately 150 meters above the destroyer. “This posed a threat to the crew of the destroyer, as it made so much noise and was shaking,” the ministry said.

The ministry then debunked the clip of the Japanese patrol aircraft that showed that it was aware of the rescue mission. “The Japanese plane continued its inappropriate reconnaissance and created a serious threat by interfering in the humanitarian mission being carried out by the South Korean destroyer,” the ministry spokesperson said, stressing that an armed warplane should not fly threateningly at a low altitude near another nation’s ship, as an accidental collision could occur between the two sides.

On Japan’s claim that it followed international law, the video claims that Japan intentionally distorted such law. Japan cited the Convention on International Civil Aviation and the enforcement regulations of the Japanese Aviation Law as the basis of the plane’s compliance with the international aviation law.

“Even though the International Civil Aviation Organization (ICAO)’s Convention on International Civil Aviation Annexes 2 to 4 provide that visual flight shall be prohibited at an altitude lower than 150 meters, it clearly stipulates that this provision is a general flight rule for the flight and safety of civil aircraft, and does not apply to military aircraft,” the ministry said. 

The ministry also clarified that the Gwanggaeto The Great destroyer operated only a search radar to rescue a vessel in distress, and never directed its STIR at the Japanese patrol aircraft.

“Despite Japan’s claim that it had detected radar frequency, the video released by Japan showed that the Japanese patrol aircraft was still flying around above the Gwanggaeto The Great destroyer. While flying at a low altitude, it confirmed that the guns of the Gwanggaeto The Great destroyer did not target it and had no intent to attack it,” the ministry said. “If the Gwanggaeto The Great destroyer targeted the patrol aircraft, it should have immediately performed evasive maneuvers. Instead, it approached the destroyer again, something that is not understandable,” the ministry added.  

The video also included the sound of actual communication from the Japanese side. According to the sound, the Japanese patrol aircraft was talking about the Gwanggaeto The Great destroyer, but only ‘Korea’ was intelligible due to noises.

“The Japanese communication was unintelligible to the Gwanggaeto The Great destroyer. Besides, it was only attempted after the Japanese patrol aircraft was relatively distant from the rescue operation area,” the ministry explained.  

“Our Navy did not engage in any threatening acts against the maritime patrol aircraft of the partner country. If there is any STIR-related evidence (radar frequency data) that supports Japan’s claim against our destroyer, it should be presented at the working-level talks between the two countries,” the ministry said, stressing that Japan must apologize for its threatening low-altitude flight toward our destroyer that was on a humanitarian rescue mission.