Gulfstream Aerospace appears to have made history by becoming the first business aircraft manufacturer to fly a production fly-by-wire aircraft—the G650—using only a digitally controlled, electrically powered flight control system.

The G650 only has two hydraulic systems, either of which can power the flight controls. The third flight control actuator system is fully electric, using Parker Hannifin electric backup hydrostatic actuators to move the ailerons, rudder, elevators and outboard wing multifunction spoilers. If both engines and both hydraulic systems fail, the pilots would still be able to fly the aircraft using the electric actuators powered by dedicated back-up batteries—or the main ship’s batteries, Ram Air Turbine or the inflight-rated auxiliary power unit. This architecture eliminates the need for a third hydraulic system.

Gulfstream tested the system on S/N 6001 during a 3-hr. and 33-min. flight on Dec. 21. Test pilots Jake Howard and Gary Freeman along with flight-test engineers Bill Osborne and Nathaniel Rutland evaluated the fly-by-wire system in electric backup actuation mode for 2 hr. and 20 min. of the flight, performing five landings with the backup system engaged. The tests included full evaluations in all axes – pitch, roll and yaw.

“There was no difference in handling qualities between the electrically and hydraulically powered modes,” says Pres Henne, Gulfstream’s senior VP, programs, engineering and test.