Former fighter pilot's perspective on Japan-Korea Radar Controversy

[The following is a translation of a blog post written by a well-respected military analyst who served in the Republic of Korea Air Force as a fighter pilot. 

He shares his insights and opinions on the ongoing Japan-Korea radar controversy.]

(Translator's comments are written in red and in paranthesis.)

Link to the original post

There has been a huge controversy surrounding an incident which took place on December 20th. South Korea claims that a Japanese P-1 maritime patrol aircraft conducted provocative actions against the Navy destroyer ROKS Gwanggaeto the Great (DDH-971) and Coast Guard vessel  KCG Sambong (5001).

These vessels were conducting rescue operation on an adrift North Korean fishing boat 180 km northeast of Dokdo Islands within the 'Japan-Korea Intermediate Maritime Zone' (한일중간수역) according to Korean claim.

'Korea-Japan Intermediate Maritime Zone' (Green)

180 km distance from Dokdo Islands; this falls within 'Korea-Japan Intermediate Maritime Zone,' which is neither Exclusive Economic Zone (200 nm) nor territorial waters (12 nm).

This is classified as international waters.

Destroyer ROKS Gwanggaeto the Great (DDH-971)

Patrol vessel KCG Sambong (5001)

Kawasaki P-1 maritime patrol aircraft

The Incident

If we look at official reports published by both sides, we can ascertain that prior to the incident:

1) Republic of Korea Navy (ROKN) was conducting rescue operation after receiving a distress signal from a 1-ton class North Korean fishing boat

2) Japan Maritime Self-Defense Force (JMSDF) was conducting surveillance operatoin against illicit maritime activity in accordance with United Nations Security Council Resolution 2397 within its Exclusive Economic Zone (EEZ).

Japanese Claims:

- P-1 approached the Korean vessels to identify friendly vessels engaged in rescue operation.

- DDH-971 activated and aimed its STIR-180 tracking radar, which is used to guide RIM-7P Sea Sparrow surface-to-air missiles.

Korean Claims:

- 1.5 meters waves in the northeastern waters of 'Korea-Japan Intermediate Maritime Zone' made tracking the1 ton-class wodden fishing boat difficult with SPS-95K navigational radar.

- DDH-971 was operating "all available radar including its fire control radar."

(MW-08 3D air search radar is classified as fire control radar [사격통제레이더 or 화기관제레이더])

- DDH-971 did not, neither intentionally nor unintentionally, emit CW (Continuous Wave) frequency, which would indicate imminent missile launch, nor actively track the Japanese aircraft.

Using STIR-180 for tracking or guidance purpose instead of search purpose against a foreign target would be classified as a "hostile act" in normal rules of engagement outside of training or closely-coordinated environment.

The location where this incident took place is neither sides' EEZ, which means it's lawfully classified as internatioal waters. As such, neithers sides should have conducted aggresive or hostile acts.


Determining Who Is Right

Was this a misunderstanding from the Japanese side, or was this a fault from the Korean side? It should actually be quite easy to determine whose story is factually correct.

Most maritime patrol aircraft are equipped with Electronic Support Measures (ESM), and a recorder that saves variety of data (Frequency, PRF/PRT, Bandwidth, frequency hopping, power density, etc) collected by ESM.

Similarly, most warships' Combat Information Center (CIC) has a recorder that saves all actions conducted by the vessel (History of radar activation & the purpose of use, IFF data, EOTS footage, etc).

If Japan or Korea want to properly & objectively debunk each other's claims:

1) Japan simply needs to release data saved on its recorder

2) Korea simply needs to release footage recorded by its on-board camera & data saved on its recorder

However, neither side has released the data record that would serve as irrefutable evidence for their claims.

It's understandable that releasing such information for public consumption would be difficult since it would exposes data-gathering capability and protocol of respective nation.

Japan's Video Footage

On December 28th, Japan Ministry of Defense released the video footage recorded by P-1 during the incident.

Full Video Footage

This 13 minutes 7 seconds video contains footage of the Korean vessels and conversation between the P-1 crew.

At approximately 6 minutes in, P-1 crew announces that DDH-971 is "emitting radar" and that "FC contact" has occurred. Shortly after, the crew attempts to communicate with the Korean ship in English, noting that they've "observed that [DDH-971's] FC antenna is directed to [them.]"

In my opinion, this is very unusual. If the aircraft's Radar Warning Receiver (RWR) truly did detect a 'LOCK on WARNING,' the response would have been much more direct.

If I were the pilot in this situation, I would have said something like:

"You are locked onto our aircraft, what is the reason?" or "Halt your action immediately!"

to directly address the LOCK on WARNING, which is a blatantly hostile act.

P-1's Altitude

Japan MoD included in the video a disclaimer that its P-1 was "flying at an altitude and a distance safe enough in compliance with the international law and related Japanese laws and regulation." 

This was in response to Korean claim that Japanese aircraft conducted provocatively low flight over its vessels, but did not include the altitude in which the P-1 was flying at.

(Pilot can be heard saying "Let's climb to 1000 feet".)

ROKN claims that P-1 flew between 1,000 and 1,500 feet.

When identifying a vessel, maritime patrol aircraft often descends to at least 500 feet. In order to identify the ship's hull number or activity on the deck, aircraft often goes lower than 500 feet. Personally, I've flown much lower on my F-5F to identify the vessel's hull number and deck activity.

Contrary to Korean claim, the altitude of 1,000 feet (330 meters) is not unusually low for aircraft in this scenario.

Some Japanese media outlets claim that the P-1 was above Noto peninsula and that DDH-971 within 12 nm from the Japanese coastline. This is a blatantly false and baseless accusation that can be disproved by this video, which doesn't show any coastline while the P-1 was flying at 1,000 feet.

The absense of visible coastline at 1,000 feet puts P-1 at least 50 nm away from the Japanese mainland, which plays in favor of Korean claim that the incident took place 180 km (100 nm) northeast of Dokdo islands in the 'Korea-Japan Intermediate Maritime Zone.'

P-1's Flight Pattern

Normal flight pattern of maritime patrol aircraft when identifying a vessel is to fly slightly high above the target vessel, circle around, and fly in parrael to the vessel's heading on its port or starboard side. This allows both sides to show that there is no hostile intent.

When approaching from the vessel's bow (front), aircraft do not fly straight at the vessel, but rather at a slightly deviated angle.

When approaching from the vessel's port or starboard side angle, the aircraft deviates course and approaches further away from stern or bow.

Directly approaching a vessel from its rear angles and straight above the vessel is a very aggressive and provocative method.

That would be more than enough to warrant a tracking radar activiation from the vessel for self-defense purpose.

US Navy P-3B flying in parallel to a Soviet Kynda-class cruiser.

The Soviet vessel is not posing any threat to the P-3B as its guns and missile launchers are at their default positions.

P-1 in the video is shown flying in low altitude and approaching the KCG Sambong from the rear and flies straight across the ROKS Gwanggaeto the Great from the rear portside direction.

This is considered an aggressive or provocative maneuver, especially against a military vessel.

Below is a photo of a US Navy P-3A conducting aggressive approach on a Soviet cargo ship during the Cuban Missile Crisis. Vessel in the bottom of the photo is a US Navy Forrest Sherman-class destroyer.

Based on what was shown in the video and on my extensive naval flight experience, Japanese aircraft's approach was undoubtedly problematic and a cause of concern for the Korean vessels.

DDH-971 Sensors & "FC Lock"

DDH-971 is equipped with AN/SPS-49(V) 2D air-search radar, MW-08 3D ground/air-search & fire control radar, SPS-95K navigational radar, and STIR-180 tracking radars.

MW-08 is one of the most ubiquotous radars in the ROKN, being installed on 9 ships, but is now one of the most outdated models. 

It was developed by Thales Naval Netherlands (formerly Signaal) and has 110 km detection range. In reality though, it has about 80 km range against planes such as B-52 or P-3, 40 km against KF-16-sized targets, and 20 km against low-altitude sea-skimming targets.

In addition, it operates in cotinuous 360' rotation instead of directing its radar at a specific target.

Next, let's move on to the STIR-180, which is the main point of contention from the Japanese side.

STIR Radar

RIM-7P Sea Sparrow surface-to-air missiles operated by DDH-971 are semi-active guidance missiles.

As shown in photos below, a radar detects and tracks the target by emitting CW (Contiunous Wave) illumination, which feeds relevant information to the missiles.

In the case of DDH-971:

1) AN/SPS-49(V) 2D air search radar initially detects the target.

2) When the target comes within 80 km, MW-08 3D air/surface search radar calculates the target's speed, altitude, and trajectory.

3) STIR-180 serves as CW illuminator and obtains precise targeting information by directly aiming its antenna at the target.

4) The information is relayed back to the ship and the missile is launched.

The reason why I'm going in details about how DDH-971's sensors function is to point out an inconsistency in the Japanese claim.

Japan claims that DDH-971 illuminated the P-1 with its STIR-180 radar. If that were the case, the dish-shaped antenna of STIR-180 would have been pointed at the P-1 and P-1's RWR would have gone off for a certain period of time when it detected CW illumination.

Photo released by Japan MoD shows that DDH-971's main gun and Goalkeeper CIWS are in their default positions.

Photo released by Japan MoD.

This particular photo shows that STIR-180's antennas are not pointed at the P-1 and that they could not have been actively tracking it.

According to the Korea claim, STIR-180 was operating in 360' mode for distance-measuring and that it was not used to actively track the Japanese aircraft.

(The author has incorrect information here; Korean Ministry of National Defense stated that its STIR-180 were not active at all. Ship's on-board camera is integrated with the STIR-180, which could explain why the antennas were turned.

 JMSDF also stated that its aircraft was not being locked on to while these photos were taken.)

At 1 minute and 4 minute mark of the video, Traffic Collision Avoidance System (TCAS)'s Traffic Alert can be heard being broadcasted. It's hard to make it out at 1 minute mark, but you can clearly hear the distinct "traffic, traffic" warning at 4 minute mark.

Why would TCAS broadcast such alarm in the middle of the ocean with no aircraft around? Warship and Coast Guard vessels are equipped with IFF/SIF and these are often misidentified as another aircraft. Since there is no altitude data to be collected, TCAS would not broadcast Resolution Advisories (RA). (IE: "Climb, climb")

It is my opinion that there was no RWR Warning and that Japanese crew mistakened the antenna as being directed towards them.

My reason for believing comes from the Japanese message to the Korean vessel. They specifically asked why the "FC antenna is directed at [them]." An actual LOCK on WARNING from the aircraft's RWR would have indicated a much more serious situation and the Japanese crew would have directly addressed the hostile act.

Thier lax attitude, lack of evasive maneuvers, no warning alarms, and continued circling of the vessels lead me to believe that there was no real LOCK on WARNING.

Official statement from the Korean Ministry of National Defense further corroborates my speculation.

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" We are extremely concerned at Japanese government's decision to release the footage of the incident just a day after an official meeting was held between the two nations to clear any misunderstandings and to discuss defense cooperation.

 As we've stated before, the fact that ROKS Gwanggaeto the Great was conducting normal rescue operation and that it did not use its STIR-180 tracking radar against the Japanese aircraft remains unchanged.

 In fact, we're deeply disappointed by Japanese aircraft's provocative flight over vessels conducting humanitarian operation.

 Video released by Japan MoD contains footage of P-1 simply circling the area and verbal communication between the P-1 crew. We cannot accept this as an objective evidence for Japanse claim that our vessel used its fire control radar to track the Japanese aircraft.

 During yesterday's meeting, we explained to Japan MoD in detail that our destroyer did not track the Japanese aircraft and requested that they provide us with obejctive and factual proof that indicates that our vessel tracked their aircraft using its fire control radar.

Japan MoD released a one-sided video meant to propogate false narrative when they should should have been cooperating with us to resolve this issue with proper understanding of international law and functioning of specific weapon systems instead. Once again, we are very disappointed.

We have been intentionally restrained in our response against Japan's brazen conduct. Despite this, we still firmly believe that Korea and Japan must work together to improve our cooperation in defense-related matters.

To do that, Japan must conduct itself in a way that clearly displays its intent to maintain a friendly relationship with our nation."

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If anything, I believe that video released by Japan further supports Korean claim than it does theirs.

(Based on all available evidence, Japan doesn't have the STIR radar emission record, and Japan needs this to prove to the rest of world that the P-1 was locked on. Japan MoD announced that it cannot release concrete evidence of STIR radar emission, citing that it's classified.)


Conclusion

1) Japanese aircraft's decision to directly approach the Korean vessels from the rear was improper and can be perceived as aggressive.

Considering that this incident took place in international waters, Japanese aircraft's maneuver can be classified as provocative act.

2) The Korean vessel were justified to activate their fire control radars in self-defense, but (according to Korean claim) knowing that it was a Japanese aircraft , it did not illuminate the P-1 and only recorded footage with its on-board camera. 

3) STIR-180 radars' antennas were not pointed at the P-1.

4) Japanese aircraft did not conduct evasive maneuvers and continuously circled the Korean vessel while conversing in normal tone despite (according to Japanese claim) being in a very dangerous situation. 

In my opinion, this minor incident deteriorated into the current controversy due to:

1) Misconception 

2) Hasty reporting

3) Lack of middle filtering of information

from the Japanese side.

It seems like Japanese leadership is politicizing this issue in order to paint South Korea as a source of external threat. I hope our government responds in a level-headed matter.

(Japanese Defense Minister and other high-ranking officials opposed releasing this video, but Abe himself ordered the release of the footage)

This controversy cannot be good for either country, who must cooperate with each other in defense-related matters.
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(The author did not address the lack of radio response from the Korean vessel after they were hailed by the Japanese aircraft.

Official Korean stance on this is that the DDH-971's crew could not properly understand Japanese accent and mistakenly believed they were calling for the Coast Guard vessel.)