Making 100% sustainable aviation fuel seems a long way away. Aircraft need energy-dense power, as delivered by fossil fuels, and sustainable alternatives are being developed. But a big challenge is that 10% - 25% of the fuel must be “aromatic” which neither thickens nor freezes at cold altitudes. Also, aromatics get absorbed by the plastic seals, make them swell, and ensure those seals between various components in the aircraft’s fuel system are … [Read more...]