Gulfstream’s G650 has flown only using its electrically powered, fly-by-wire backup flight-control actuation system.
Test pilots Jake Howard and Gary Freeman and flight test engineers Bill Osborne and Nathaniel Rutland evaluated G650 serial number 6001’s fly-by-wire system in electric backup actuation mode for 2 hours and 20 minutes of the 3 hours and 33 minute flight on December 21, performing five landings with the backup system engaged.
“It flew so well that unless pilots were told they were in backup actuation mode I don’t think they would notice,” said Freeman.
Fly-by-wire technology typically uses a third hydraulic system as a safety backup in the event of a dual hydraulic system failure. However, Gulfstream’s fly-by-wire electric backup hydraulic actuators (EBHA), while still primarily hydraulically powered, offers electric power as a backup, with a self-contained hydraulic reservoir and motor pump to allow full aircraft operation should hydraulic loss occur.
The G650 is fitted with Parker Hannifin manufactured EBHAs on every primary control surface (elevator, rudder and aileron), as well as the outboard spoiler, designed to enhance safety and aircraft availability because of the two different power sources. Gulfstream claims this will be a considerable advantage in the “extremely rare” event of catastrophic failure, such as a rotor burst.