The reported downing of a Sukhoi-35 by Ukraine could have important tactical lessons for the Chinese military, which holds the world’s second largest fleet of the fighter jets after Russia. As the war in Ukraine entered its 40th day, a video emerged apparently showing the moment the jet fell from the sky in flames before exploding. Pictures of the burned-up wreck were later posted on social media. Ukraine said the Su-35 was shot down near Kharkiv by its anti-aircraft missile forces, in what Ukrainian deputy interior minister Anton Gerashchenko said amounted to “US$50 million worth of damage” for the Russians. Zhou Chenming, a military analyst in Beijing, said that judging from the images of the wreckage, “which has maintained its shape, the fighter jet appears to have gone down from a very low altitude”. “It was probably on its return from a ground attack mission and the fire was likely from the leftover fuel it was carrying,” he said. Flying at low altitude would increase the risk of attack from anti-aircraft weapons, and even from portable air-defence missiles such as Stingers and Starstreaks. But Zhou said it could also be that the fighter jet had a mechanical failure. “To learn from this, the Chinese air force will need to carefully identify potential mechanical problems with its own Su-35s and improve maintenance,” he said. China signed a US$2 billion contract with Sukhoi in 2015 for 24 of the 4.5 generation super manoeuvrable aircraft which represent Russia’s main force of modern fighter jets. Around 100 Su-35s have been added to the Russian air force since 2013. Egypt has also ordered two dozen Su-35s at US$2 billion and received the first delivery last year. The China deal was specifically included in US sanctions in 2018 against the Central Military Commission’s equipment development department and its director over the purchase of Russian weapons. Soon after deliveries were completed in 2018, Su-35SKs joined People’s Liberation Army patrols in the increasing missions over the South China Sea and around the self-ruled island of Taiwan. The Su-35 single-seat, twin-engined fighter inherited long operational range, a large armaments payload and strong dogfighting skills from its predecessor the Su-27. But it has been suggested China was most interested in its advanced thrust vectoring engines. But the PLA Air Force has placed no further orders for the Su-35. Instead, China has been mass producing its home-grown J-16, another variant of the Su-27 which features more advanced avionics, also developed in China. While the Su-35 is more of an air combat fighter, the J-16 is equipped with stronger ground and sea attack armaments. The fifth-generation stealth fighter J-20 is preferred for an air superiority role, assisted by the Su-35.