Russian Su-57 fighter jet exploded during engine startup, Ukrainian intelligence says
A Russian Su-57 fighter jet exploded during engine startup at the Akhtubinsk military airfield in Russia on October 29, Ukraine's military intelligence agency (HUR) reported on November 2. The agency suggested poor-quality fuel as one possible explanation but did not establish the cause of the explosion.
The Su-57, Russia's most advanced operational fighter aircraft, is estimated by HUR to cost approximately $150 million.
The aircraft is powered by AL-41F1 turbofan engines, which can suffer catastrophic failures for several reasons, including fuel-quality problems, the agency said.
HUR linked the incident to broader concerns about Russia's growing dependence on imported aviation fuel as Ukrainian long-range strikes disrupt domestic oil refining.
However, the agency did not provide evidence that the destroyed aircraft had been refueled with substandard fuel or that imported fuel caused the explosion.
Russian aviation fuel imports
According to HUR, Russia has increasingly relied on aviation fuel shipments from India's Vadinar refinery, operated by Nayara Energy, in which Russian state-owned oil company Rosneft holds a 49.13% stake.
On August 22, the sanctioned tanker GRIF transported nearly 40,000 metric tons of Jet A-1 aviation fuel from the refinery, HUR said.
The cargo was subsequently transferred at sea to another sanctioned tanker, HALCYON, near Malaysia in early September.
On September 23, HALCYON delivered more than 37,000 metric tons of aviation fuel to the Russian port of Nakhodka, according to the agency.
HUR also said Rosneft subsidiary RN-Aero supplies aviation fuel to Russia's United Aircraft Corporation under contracts related to Su-57 production.
The intelligence agency noted that Jet A-1 fuel is compatible with Russian military aircraft, including the Su-57, Su-35 and Su-34.
The reported explosion at Akhtubinsk has not been independently verified.