Boeing’s “more-electric” power architecture for the 787 will face special conditions to achieve airworthiness certification by the US FAA.
The extra certification requirements released today by the FAA require Boeing to prove that the 787 “is capable of recovering adequate primary electrical power generation for safe flight and landing” in the event of an in-flight power failure.
Boeing’s older airliners use pneumatic systems to power the hydraulics controlling flight control systems and landing gear, with comparatively small electric generators needed for onboard electronic systems.
But the 787 design omits the heavier pneumatic system in favor of electric power for the hydraulic actuators.
This change requires the aircraft’s two engines to drive four integrated drive generators providing 1.45MW of electricity, . The flight controls and landing gear depend on the electric generators as a primary power source.
The FAA recognizes the 787’s electric power as a potential safety concern that must be addressed by imposing special conditions beyond its normal airworthiness-proving requirements.
Boeing must show that the 787 is capable of safe flight with the engine and APUs inoperative. Alternate sources of power may include the battery, ram air turbine or a permanent magnet generating system.
The manufacturer also has to prove that the 787 has enough alternate sources of electrical power onboard to descend from the maximum operating altitude to the minimum altitude to attempt an engine and APU restart.
Source: flightglobal.com's sister premium news site Air Transport Intelligence news
Source: FlightGlobal.com
