The RC-135U in question, which bears the serial number 64-14849, flew its mission near areas of China’s southern coast, including around Hainan Island and in the Gulf of Tonkin, on June 6 , according to online flight tracking data. It is now June 7 in this part of the world. Hainan is home to the highly strategic Yulin Naval Base, the main hub of the People’s Liberation Army (PLAN) Navy in the region and its main nuclear submarine base, where all of its ballistic missile submarines are based, among others.

The route, which kept the aircraft in international airspace very close to Chinese territory the entire time, is similar to that which a US Navy EP-3E Aries II, another collection platform of electronic intelligence, was flying at the time of a now infamous crash. with a People’s Liberation Army J-8 fighter jet in 2001.

This same aircraft, one of only two RC-135Us in service, flew another sortie that similarly brought it close to areas along much of China’s central and northern coasts on June 3. Both sorties were flown from Kadena Air Base on the Japanese island. from Okinawa.

We don’t know for sure what the exact purpose(s) of either of these recent outings may have been. The Air Force‘s pair of RC-135Us are highly specialized platforms configured to collect a wide range of signals and other electronic intelligence. Unlike the service’s larger fleet of RC-135V/W Rivet Joints, which have similar capabilities, these aircraft are primarily used to meet technical electronic intelligence (TechELINT) requirements at the national level.

“Technical ELINT…describes the signal structure, emission characteristics, modes of operation, transmitter functions, and weapon system associations of transmitters such as radars, beacons, jammers and navigational signals,” according to an unclassified National Security Agency monograph. “A primary goal of TechELINT is to obtain signal parameters that can define the capabilities and role the transmitter plays in the larger system, such as a ground-based radar tracking aircraft, and thus lead to the design radar detection, countermeasures or counterweapons The whole process, including the operation of countermeasures, is part of electronic warfare.

The geolocation and categorization of radars and other signal transmitters is an essential part of producing accurate “electronic battle orders” regarding the air defense capabilities of adversaries or potential adversaries. The RC-135Us, which can process onboard intelligence data and transmit near real-time information, can also be deployed to support tactical-level operations in a contingency scenario, as well as perform various test and devaluation.

Although not necessarily common, partly due to the small number of RC-135Us departing, combat flights sent to these areas of the Pacific are a regularized event. The Air Force, at least in the past, applied the monikers Diamond Sent and Sapphire Sent, to sorties covering parts of the East China Sea and South China Sea, respectively.

Last June, Combat Sent 64-14849 flew another very similar mission along the coasts of southeast China, which also drew comparisons to the route of the EP-3E during the 2001 incident. .

There is certainly no shortage of radars and other signal transmitters of potential interest for an aircraft like the RC-135U along the Chinese coast, and around the Yulin naval base in Hainan in particular. Other US military intelligence, surveillance and reconnaissance (ISR) aircraft, including at least one US Navy P-8A Poseidon maritime patrol aircraft fitted with a secret radar pod, have been tracked on similar routes in the past.

The route could also have given the RC-135U the ability to collect data on various Chinese assets to the south on Woody Island and the Paracel Islands chain. The PLA has actively expanded the size and scope of facilities on Woody Island and the Paracels in recent years as part of a broader effort to build its capabilities and overall presence across the South China Sea. . The region is now dotted with fortress-like and largely man-made outposts created from various previously uninhabitable shoals and reefs. The government in Beijing claims almost all of this body of water as its sovereign national territory, which the vast majority of the international community disputes.

A Tweet yesterday from the SCS Probing Initiative, a public flight and ship tracking effort led by Peking Chinese University in Beijing, further speculated that the RC-135U’s proximity to the shore during its recent flights could give it the ability to collect data on targets deeper inland.

Routine or not, the overall timing of these recent RC-135U releases is notable for a number of reasons.

This weekend, the Australian government released statements regarding what it said was a particularly dangerous interception of one of the Royal Australian Air Force P-8As flying over the South China Sea by a PLA fighter jet. D-16 in May. The Chinese fighter crossed the path of the Australian aircraft and fired decoys and chaff, apparently causing damage in the process, as you can read more about here.

Last week, Canadian authorities released details of what they said were dangerous interceptions of Royal Canadian Air Force CP-140 Aurora maritime patrol aircraft by Chinese fighters between April and May this year. In these cases, Canadian aircraft were flying much further north in support of an international mission monitoring North Korea’s compliance or non-compliance with United Nations sanctions.

China’s reported harassment of foreign ISRs and other aircraft, particularly those flying over international waters in hotly contested southern China, is of course not new.

Moreover, the appearance of the RC-135U off the coast of China follows a major PLA show of force targeting Taiwan last week. A total of 30 Chinese military aircraft, including a mix of 22 fighter jets of various types, as well as various airborne early warning and control, electronic warfare, anti-submarine and ISR aircraft, flew in the southwest corner of the island. Defense Identification Zone (ADIZ) on May 30. It was the highest number of sorties in this part of Taiwan’s ADIZ since Jan. 23, when 39 Chinese aircraft flew missions there.

The Chinese government has sent a large number of military aircraft to this area of ​​Taiwan’s ADIZ, which is international airspace, in recent years. These large-scale thefts usually occur in response to actions by the Taipei authorities or their international partners, including the United States, which the Beijing government opposes. The May 30 exits came days after US President Joe Biden said the United States would defend Taiwan against any attempts by mainland authorities to seize it by force, comments that were quickly reprimanded by the government. Chinese and which were then rebuffed by US officials.

US military officials, as well as members of the US intelligence community, have said in recent years that they believe the PLA is working to at least put itself in a position where it is confident in its ability to conduct a successful military intervention against Taiwan in 2027. US officials have also said they do not believe this necessarily means the government in Beijing will rush to launch such an operation then. At the same time, there have been many discussions about what Chinese officials might gain from the international response to Russia’s invasion of Ukraine. The government in Beijing criticized the sanctions and other measures taken in response to Russia’s aggression, but therefore appeared to provide only limited measures to Moscow.

Either way, the recent flight of RC-135U 64-14849 along the Chinese coast in the South China Sea, as well as the previous one near areas further north, underscores the military’s clear interest American to have the most recent and detailed information. possible on Chinese radars and its integrated air defense system as a whole, in this highly strategic part of the world.

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