During the approach to clean stall, the stall warning stick shaker fired at 129 KIAS or 0.94 normalized AOA. At 0.97 AOA, the FBW system limited elevator and horizontal stabilizer pitch control authority to prevent untoward handling characteristics. Holding the control wheel fully aft, the nose gently pitched down and we initiated recovery.
The dirty stall, with gear down and flaps extended to the full 39 deg., was equally non-dramatic. We trimmed for 122 KIAS or 0.67 AOA, began a normal glidepath-like descent and then leveled off without adding thrust, thus allowing the aircraft to decelerate. After the stick shaker fired, we continued to pull aft on the yoke until reaching the stops. At 0.98 normalized AOA, the nose gently dropped and we initiated recovery with only a slight loss of altitude.
Returning to Savannah, we prepared for a WAAS LPV (wide area augmentation system with vertical guidance approach procedures) to Runway 19. Horne computed Vref at 120 KIAS for a 65,500-lb. landing weight and a non-factored landing distance at 2,873 ft. based upon 13-kt. headwinds.
We bugged the target airspeed at 125 KIAS and let the auto-throttles maintain speed in gusting wind conditions.
The HUD's azimuth and glidepath guidance cues, along with the FPV marker, made it easy to hand fly the approach.
The FBW system transitions from high-level control law to direct law for takeoff and landing, so G650's smooth handling behavior during final approach reflects its aerodynamic refinement. At 50 ft., we pulled back the thrust to idle and continued to use the HUD until touchdown. We deployed the thrust reversers, lightly touched the brakes and turned on to a taxiway after a touchdown roll of about 5,200 ft.
Earlier we flew one engine inoperative (OEI) takeoff and landing in the G650 simulator at FlightSafety International's Savannah training center. Rudder pedal forces on the OEI takeoff were moderate and the aircraft was easy to control. For landing, though, we could not use the auto -throttle because the system only works if both engines are operating. Managing the asymmetric thrust, however, was not difficult.
Conclusions? G650 is the nicest flying large-cabin Gulfstream yet built. The FBW functionality is all but transparent unless probing the extremes of the flight envelope. Pilots might not know it's a FBW aircraft without being told. PlaneView II, the HUD and EVS, among advanced cockpit features provide unsurpassed situational awareness. The cabin environment, including increased volume, window size and pressurization, along with the redundancy and reliability of the cabin management system, make it Gulfstream's most commodious and functional business aircraft yet.
Being able to cruise at Mach 0.80 may have been the benchmark in the 20th century, but it seems slow by 21st-century standards. Even long-haul airliners now can cruise at Mach 0.85. Bombardier indeed routinely quotes Mach 0.82-0.85 as the normal cruise speed for its current production Global series business jets.
The G650 now raises the standard with its Mach 0.90 high-speed cruise and 6,000 nm range. Slow it to Mach 0.85 and go another 1,000 nm. Among purpose-built business jets, G650 has the best fuel efficiency while cruising at Mach 0.85.