PETALING JAYA: A US aircraft impersonated a Malaysian airplane’s transponder code as it flew over the disputed South China Sea, said a report.
Technology magazine Popular Mechanics said this was detected by Chinese government think tank SCS Probing Initiative, which posted their findings on Twitter.
The think tank said the RC-135W Rivet Joint reconnaissance aircraft had left Kadena US air base on Okinawa island in Japan at 3am on Wednesday, before turning off its transponder shortly after.
“The plane’s International Civil Aviation Organisation (ICAO) Mode-S number, a 24-bit identifier assigned to all aircraft and broadcast by onboard transponder, was AE01CE,” said the report.
Later, a plane appeared on the same route with a different Mode-S number of 750548, which belongs to an unknown Malaysian aircraft, entering the Yellow Sea and hovering over it from 5am to 11am.
“The RC-135W, call sign RAINY51, then flew a racetrack pattern between Hainan Island and the Paracel Islands, an archipelago in the South China Sea that China claims, but whose ownership is in dispute,” it said.
The report said the RC-135W Rivet Joint is a Boeing 707 jetliner converted and designed to collect electronic intelligence for analysis.
It said planes sometimes broadcast the wrong Mode-S number by mistake, although it said it was highly unlikely for the US aircraft to have accidentally changed its transponder code.
It said it was unclear why the US aircraft flew in the area.
The Twitter account of the South China Sea Probing Initiative shared a pair of screenshots that showed a RC-135W take off from Kadena Air Base, a U.S. Air Force base on the island of Okinawa. The plane flew southwest, following the Ryukyu islands chain, past Taiwan, to loiter off the coast of Hainan Island.
The plane’s International Civil Aviation Organization (ICAO) Mode-S number, a 24-bit identifier assigned to all aircraft and broadcast by onboard transponder, was AE01CE. The Mode S system provides big-picture situational awareness and improves aviation safety.
At some point, the plane’s Mode-S number suddenly changed, from AE01CE to 750548. That’s the ICAO number for an unknown Malaysian aircraft. The RC-135W, call sign RAINY51, then flew a racetrack pattern between Hainan Island and the Paracel Islands, an archipelago in the South China Sea that China claims, but whose ownership is in dispute. Here’s another screenshot from a plane-tracking app that shows the same flight:
Parts of the South China Sea are subject to rival claims by Brunei, Malaysia, the Philippines, Taiwan and Vietnam while Beijing claims the entire waterway.
The rival claims to the sea, which straddles vital shipping lanes and covers rich fishing grounds, make it a potential flashpoint for conflict.
China and Asean – of which four claimants are members – are currently in talks for a code of conduct in the area.
Most recently, Prime Minister Muhyiddin Yassin and Senior Minister for Security Ismail Sabri Yaakob had met China’s defence minister to discuss the South China Sea issue, among other matters.