Fuel Tank Ignition Could Occur Due To Overheating Hydraulic System
EASA has issued an emergency AD (2017-0154-E) for all Airbus A350-941 airplanes following the recent discovery of an overheat failure mode of the the A350 hydraulic Engine Driven Pump (EDP). Such EDP failure may cause a fast temperature rise of the hydraulic fluid. This condition, if not detected and corrected, combined with an inoperative Fuel Tank Inerting System (FTIS), could lead to an uncontrolled overheat of the hydraulic fluid, possibly resulting in ignition of the fuel-air mixture in the affected fuel tank.
To address this potential unsafe condition, Airbus has issued a Major Event Revision of the Airbus A350 Master Minimum Equipment List (MMEL) that incorporates restrictions to avoid an uncontrolled overheat of the hydraulic system.
Before the next flight after the effective date of this AD, operators are directed to implement the MMEL changes in accordance with Airbus A350 MMEL Major Event Revision dated August 21, 2017, and inform all flight crews, and, thereafter, operate the airplane accordingly.
For the reasons described above, this AD requires implementation of those Airbus A350 MMEL changes and, consequently, restrictions for airplane dispatch. This AD is considered as an interim action and further AD action may follow.
(Image from file)