There's a new super-midsize champ.
Belt into the left seat of the G280, as we did in late August 2012, and it's immediately clear that its PlaneView280 flight deck puts this aircraft on par with the best of Gulfstream's large-cabin aircraft. Brian Dickerson, senior production test pilot for Gulfstream, accompanied us as instructor pilot in the right seat of s.n. 2004 and Bob Wilson, midsize Gulfstream aircraft experimental test pilot, rode along as safety pilot.
Dickerson explained that the G280 is the only aircraft in this class to have both full-authority auto throttles and an auto braking system. It's also the only super-midsize aircraft in current production offering optional HUD and EVS, although the demonstrator wasn't so equipped. We noted thatplans to offer optional HUD and EVS on the Legacy 500 when it arrives in late 2013.
PlaneView280 has three 15-in. landscape configuration displays instead of the four 14-in. units used in larger Gulfstream aircraft. Each screen may be divided in half or quarters, providing as many as a dozen different images. It's easy to learn how to select various functions. Must-have functions are all top level, mostly selected by discrete controls. Nice-to-have functions are selected by using cursor control devices on the outboard side ledges.
The glareshield has left- and right-side standby multifunction controllers (SMC) adapted from the units aboard the G650 that function both as integrated standby instrument systems and display controllers. The SMC also provides APU start and operation monitoring when the aircraft batteries are the only source of electrical power.
The center section has the flight guidance control panel with direct readouts for speed, heading/track, vertical speed/flight path angle and preset altitude, that aid hand/eye coordination. These same data are available on the display screens.
Dickerson and Wilson prepped the aircraft and they had the APU running when we arrived at Gulfstream's Dallas-Love Field facility (elevation 487 ft.). Outside, the temperature was 33C/91F, but inside the aircraft it was 21C/70F.
Pre-start checks were straightforward, including use of the standby multifunction controller to run through stall, TCAS and TAWS tests, plus setting the landing field elevation. The FMS performance database is not yet certified, so Wilson computed takeoff data for a 32,000-lb. takeoff weight and flaps 20 deg. He calculated 106 KIAS for V1 takeoff decision speed, 112 KIAS for rotation and 124 KIAS for the V2 OEI takeoff safety speed. En route climb speed was 171 KIAS. Using those speeds and opting for a “bleeds off” takeoff, we computed takeoff field distance at 3,725 ft. The APU would furnish bleed air for air-conditioning and pressurization until after takeoff.
Rolling out of the chocks, we found the nosewheel steering and new brake-by-wire system to be smooth and precise. We reflected on how far brake-by-wire systems have progressed since the original GIV's primitive system of the mid-1980s.
Once cleared for takeoff on Runway 13R, we advanced the throttles midway and engaged the auto-throttle system. Rpm advanced to 90.6% N1, providing nearly 7,600 lb. of thrust on each engine. With a weight-to-thrust ratio of 2.11 to 1, acceleration was spirited.
Rotation force was moderate and roll force was well harmonized with pitch force. The ailerons and elevator have virtually no perceptible on-center stiction, making the aircraft quite enjoyable to hand-fly. In addition, thrust change causes very little pitch change. Some pilots may not want to relinquish control to the autopilot. But the auto-throttle system is so smooth and precise that there's little reason not to use it.
After takeoff, the pneumatic system automatically switched from APU bleed air to engine bleed air. At that point, we secured the APU.
Following a 250 KIAS/Mach 0.75 speed schedule, the aircraft climbed to FL 450 in 21 min., including a 3 min. ATC delay. That's impressive as the OATs were mostly ISA+15C to 17C until we climbed above FL 300. At FL 450, though, OAT cooled off to ISA-5C. Fuel burn for the climb was about 1,000 lb.
We checked cruise performance at Mach 0.80 normal cruise and Mach 0.84 high-speed cruise at FL 450 at ISA-5C to -6C temperatures. At a weight of 30,800 lb., fuel burn was 1,510 pph at normal cruise and 1,810 pph at high-speed cruise. Gulfstream's AFM indicates the aircraft's long-range cruise speed at this weight is Mach 0.79 and fuel flow should be about 1,400 pph. At Mach 0.84, the book predicts 1,778 pph at that weight and OAT.
We also checked buffet boundaries. The aircraft was buffet free up to 40-deg. angle of bank, corresponding to 1.3 g. At MTOW, the aircraft has 1.2 g of buffet margin from Mach 0.75 to 0.80 at FL 450. Buffet margin drops sharply above normal cruise speed.
We descended to 16,000 ft. for airwork southeast of Abilene, Texas, using idle thrust and the variable position speed brakes for drag. The air brakes produce very mild pitch-up when fully extended and just slight airframe rumble that's unlikely to disturb passengers.
Once level at low altitude, we flew a couple of steep turns. It's easy to maintain altitude using the PFD's flight path marker and airspeed trend vector. Pitch force is moderately heavy, thereby preventing over-control. Roll response, with the help of the FBW roll spoilers, is crisp, but roll effort is moderate, again preventing over-control. Dickerson commented that pilots aren't allowed to use the flight path marker on check rides.
Dickerson next demonstrated the aircraft's low-speed protection system. If the aircraft is slowed to 72% of the angle of attack (AOA) at which the stall warning stick pusher fires, the auto-throttle system automatically engages and power is advanced to prevent the stall. Up to maximum available thrust, the auto-throttle system will not allow angle of attack to exceed 78% of stick pusher AOA.
We then flew clean, flaps 20 approach and landing configuration stall approaches to stick pusher at weights of 30,150 lb. to 30,250 lb. For the three configurations, stall warning stick shaker then stall prevention stick pusher respectively were triggered at 139 KIAS and 131 KIAS, 113 KIAS and 106 KIAS, and 107 KIAS and 101 KIAS. Aircraft behavior during each of the maneuvers was very benign.
Next, it was off to Abilene's Runway 35R for pattern work, starting with the ILS approach. Wilson pegged Vref at 128 KIAS for the aircraft's estimated 29,600-lb. landing weight, providing a 23% margin over stall. Dickerson set the auto-braking system to medium deceleration for demonstration purposes.
We flew the approach at Vref+5 until crossing the fence. The relatively large wing and absence of leading edge slats/Kreuger flaps provides considerably more ground effect cushioning than in the G200. We floated down the runway for a few hundred extra feet before the aircraft touched down. Auto braking action was very smooth and progressive. The aircraft slowed to moderate taxi speed in about 2,500 ft.
It was then time to sample the G280's engine-out takeoff performance. Wilson computed speeds of 101 KIAS for V1, 109 KIAS for rotation and 121 KIAS for V2. Just above 101 KIAS, Dickerson retarded the right throttle to idle, simulating an engine failure. Only light left rudder pressure was needed to control yaw because of the powerful FBW rudder system. But the servo system moved the rudder pedals enough to make it apparent to our feet that the left engine was producing substantially more thrust than the right engine.
The aircraft was easy to control throughout the simulated OEI approach and landing. We noted that thrust response to throttle movement is very linear and predictable with theHTF7250 turbofans, thus speed was easily controlled. That's a vivid contrast to the throttle response of the PW306C engines that power the G200.
After landing, we taxied back to sample the aircraft's auto braking rejected takeoff feature. During our simulated takeoff roll, Dickerson called “Abort! Abort!” just past 80 KIAS. We snapped the throttles to idle. The ground spoilers fully deployed and the auto braking responded with maximum braking effort. There was the slightest tendency toward triggering the anti-skid system, but the aircraft decelerated smartly to a stop with no loss of directional stability.
Returning to Dallas-Love Field, we noticed that, compared to the G200, the aircraft's considerably larger wing and relatively stiff wing structure results in a firmer ride in turbulence. It feels similar to a G450.
We landed 1 hr., 49 min. after departing Love Field and easily stopped the aircraft in the first 3,800 ft. of runway.
Conclusions? The G280 delivers sporty performance, excellent handling qualities and unsurpassed avionics capabilities in this class of business aircraft. Its range, speed and systems capabilities are on a par with far more expensive large-cabin aircraft, placing it at the top of its class.