US Patent 10370114 Aircraft fuel tank inerting systems

An aircraft fuel tank inerting system for a fixed wing aircraft having at least one main fuel tank in the wing and an associated surge tank includes a source of inerting fluid and a flow passage for supplying said inerting fluid to the main fuel tank and discharging it into the main filet tank through at least one discharge outlet. The flow passage includes a pressure relief arrangement adapted to discharge into the surge tank if a pressure in the main fuel tank exceeds a predetermined threshold.