The Air Force has certified the C-17 to operate unconstrained on fuel blends containing biofuels known as hydrotreated renewable jet fuels, or HRJs. “This certification marks the Air Force’s first platform to be fully certified using an HRJ blend,” said Kevin Geiss, USAF’s deputy assistant secretary for energy. He added, “This marks a significant achievement.” C-17s may now fly using fuel blends containing up to 50 percent HRJ and 50 percent traditional JP-8 aviation fuel or a blend of 25 percent HRJ, 50 percent JP-8, and 25 percent synthetic paraffinic kerosene fuel, another type of alternative fuel that Air Force officials have cleared for use. Jeff Braun, who heads USAF’s alternative fuel certification office, said officials expect to conclude HRJ flight testing on other platforms “within the next 12 months, supporting fleetwide HRJ certification within the next 22 months.” (SAF/PA report by Maj. Richelle Dowdell)
The Air Force overall reduced its size by 120 aircraft in fiscal year 2021, but kept about the same number of fighter, bomber and attack aircraft, according to data supplied by the service. The F-35 fleet saw the biggest increase while the B-1B bomber fleet saw the largest decline.