Despite the well documented complications arising out of the Boeing 787’s “more electric” architecture, French engine and equipment manufacturer Safran earlier this month restated that electric systems will replace hydraulics and bleed air in future aircraft at an accelerated rate. The group, which includes companies like Snecma, Hispano-Suiza, Sagem and Labinal, disclosed numbers that highlight how electric systems have become a strategic research area.
Onboard electric power and systems will account for eight to 10 percent of an “all electric” short- to medium-haul jet's value, according to Safran, which has spent €250 million ($350 million) in two research and technology programs. Meanwhile, the European Union’s Clean Sky joint technology initiative has been using Hispano-Suiza’s “copper bird” testbed for aircraft electric networks. In 2009, Safran also created a new entity, Safran Power, employing 130 design engineers and technicians.
Today, electricity powers some 15 percent of the systems of in-production aircraft. Safran has set an ultimate goal of 100 percent by around 2020. The Boeing 787, now in development, lies somewhere in between. For example, its wing-deicing system and brakes use electric systems, instead of pneumatic and hydraulic, respectively.
Weight remains a major challenge, Safran said. On in-service aircraft, one kilogram (2.2 pounds) of electric-power hardware provides one kilowatt. Technologies undergoing laboratory testing aimed at raising the ratio to three to four kilowatts per kilogram would achieve about half of the required power density. The Paris-based group’s target stands at eight kilowatts per kilogram.
The major incident that happened last fall on a flight-test 787 does not seem to have changed Safran's views. During a November 9 flight, an electric fire started in an electric-power distribution panel. The malfunction should have been confined to one electric system, allowing the aircraft, thanks to built-in redundancy, to safely use the second system. But the problem spread to the second electric system so that the ram-air turbine–a last-resort backup device–deployed. As a result, the program suffered a further six-month delay.