Why The Rolls-Royce Trent XWB & GEnx Can Burn 100% SAF But Still Aren't Certified To Do It

Despite tests proving that Rolls-Royce's Trent XWB and GE's GEnx engines can technically run on 100% sustainable aviation fuel (SAF), they still only have certification for using up to 50% SAF. This limitation stems from regulatory and certification processes that are conservative and take time to update. The ability to use 100% SAF is crucial for meeting the industry's ambitious carbon reduction targets and aligns with the global push for greener aviation practices. This situation highlights the gap between technological capability and regulatory approval, which can slow down the adoption of cleaner fuels.