PH aircraft challenges Chinese vessel off Cagayan

MANILA, Philippines — The Philippine Coast Guard (PCG) deployed its aircraft to conduct a Maritime Domain Awareness (MDA) flight and challenge the Chinese research vessel Tan Suo Er Hao monitored off Cagayan province in northern Luzon on Tuesday.

In a post on X, PCG West Philippine Sea spokesperson Commodore Jay Tarriela reported that the vessel was detected approaching within about 19 nautical miles off Cagayan using Canada’s Dark Vessel Detection program.

In response, Tarriela said, the PCG Islander aircraft was dispatched to conduct an MDA flight, challenge the vessel’s presence, and verify whether it was conducting marine scientific research without prior consent from the Philippine government.

“The CRV Tan Suo Er Hao, an 87.25-meter advanced deep-sea scientific research vessel operated by the Institute of Deep-sea Science and Engineering under the Chinese Academy of Sciences, serves as a mothership for manned and unmanned deep-sea submersibles and supports comprehensive deep-sea operations,” Tarriela wrote.  

“Monitoring indicated that the vessel departed from Hainan province in China earlier this month and transited through the western Philippine EEZ. During the MDA flight, the PCG aircraft sighted the CRV heading eastward at coordinates Latitude 18°34.021′ N, Longitude 123°17.042′ E, approximately 55.78 nautical miles east of Santa Ana, Cagayan,” he added.

Tarriela said the aircraft’s pilot issued multiple radio challenges to the vessel, asking about its intentions and reminding it of the requirement for prior consent for marine scientific research in Philippine waters. 

PCG Challenges Chinese Research Vessel Operating Near Cagayan WatersThe Philippine Coast Guard (PCG), utilizing the Canada’s Dark Vessel Detection program, detected the Chinese Research Vessel (CRV) Tan Suo Er Hao approaching within approximately 19 nautical miles off the coast… pic.twitter.com/8xUl9aZla6

— Jay Tarriela (@jaytaryela) December 30, 2025

However, he said that the vessel did not respond to any of PCG’s radio challenges. 

“The Philippine Coast Guard remains vigilant in protecting the country’s maritime domain and will continue to monitor and challenge unauthorized activities within the Philippine EEZ in accordance with the directive of President Ferdinand Marcos, Jr, of upholding national sovereignty and maritime laws,” he said.

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Since early 2025, Philippine authorities have been monitoring the movements of China Coast Guard vessels “unlawfully operating” within the country’s exclusive economic zone.

Beijing’s ongoing aggression stems from its broad claim of sovereignty over nearly the entire South China Sea, including much of the West Philippine Sea, and its continued rejection of the 2016 arbitral ruling that invalidated its claims and favored Manila./mcm