EASA has issued an emergency airworthiness directive aimed at preventing the Airbus A350 from experiencing overheating of hydraulic fluid, leading to possible explosion. The manufacturer has also issued a major event revision of the A350 Master Minimum Equipment List, EASA said.
“Recently, an overheat failure mode of the A350 hydraulic engine-driven pump has been found,” the directive states. “Such failure may cause a fast temperature rise of the hydraulic fluid.”
If this is not detected and corrected, the directive continues, it could result in an uncontrolled overheat of the hydraulic fluid, if combined with an inoperative fuel tank inerting system. This could lead to ignition of the fuel-air mixture in the affected fuel tank — an explosion.
Airbus’ major event revision includes restrictions to avoid this scenario. Before next flight, after the effective date of Aug. 24, changes to the equipment list must be implemented, EASA said. After all flight crews are informed, the aircraft can be operated accordingly.