The Air Force is looking to use alternative aviation fuel mixtures that contain up to 50 percent biomass-derived fuel or synthetic fuel in combination with 50 percent traditional JP-8 fuel, says Jeff Braun, alternative fuels certification office director at Wright-Patterson AFB, Ohio. Already, fleet-wide certification of a 50-50 blend of JP-8 and synthetic paraffinic kerosene is nearing completion. Now, the focus is on approving mixtures that feature some percentage of hydro-treated renewable jet fuel that is derived from biomass. Braun told the Daily Report that any combination of HRJ and SPK that adds up to 50 percent of the fuel blend could be possible as long as it meets the Air Force’s specifications for performance and safety. The service is “agnostic” with respect to the HRJ source, be it animal fat (e.g., beef tallow, chicken fat), plant oil (e.g., camelina or algae), or a combination thereof, he said.
Depot-level maintenance took longer than expected for nearly three-quarters of Air Force aircraft from fiscal 2019-2024, according to a new report, as unplanned repairs rise across the aging fleet. The report, from the Government Accountability Office, also found that the extent of the delays has been masked because officials often revise their target timelines after unplanned work occurs.