The latest entry in the 'super midsize' competition is put through its paces
soon will begin customer deliveries of its $24-million G280, a 3,600-nm-range super midsize jet.
Although not new to the category—Gulfstream acquired the Galaxy (nee Israel Aerospace Astra IV) in 2001 and renamed it—the G200's performance was inferior to's muscular Challenger 300, which went on to garner nearly 400 sales in the past decade. Nonetheless, G200 operators say their passengers loved the cabin and the aircraft's reliability. Gulfstream, along with Galaxy Aerospace, succeeded in delivering more than 240 aircraft.
Still, to remedy the G200's shortcomings, Gulfstream gave its successor a new wing and empennage and replaced the 6,040-lb.-thrust Pratt & Whitney PW306A engines with a pair ofHTF7250G turbofans, each rated at 7,624 lb. thrust, giving it the best thrust-to-weight ratio and runway performance in the category. And it boasts a more tanks-full payload, 350 nm more range and better fuel efficiency than its Canadian competitor.
Of equal importance to operators, G280 has more cabin volume than either Challenger 300 or G200, along with a lower cabin altitude and reduced cabin sound levels. Its 120-cu.-ft. aft baggage compartment is the largest in its class and it is now accessible inflight because the G200's aft fuselage fuel tank has been eliminated. G280's cabin has 19 windows—four more than G200.
Up front, there is large, full-service galley and a cockpit jump seat for the flight attendant. The aft lavatory has a vacuum toilet, a first for a super midsize aircraft. And all the way up front, the G280 features a PlaneView flight deck, which will be discussed more fully when we outline the flying characteristics later in this article.
Before taking to the air, it's good to note the regulatory milestones that have been met. G280 has new CAA Israel andPart 25 type certificates, and complies with Federal Aviation Regulations (FAR) Part 25 through Amendment 1-120, plus A122. The CS-25 A2 type certification is in the works. The aircraft meets International Civil Aviation Organization Annex 16 and FAR Part 36 Stage 4 noise standards, along with FAR Part 34 fuel venting and exhaust emission requirements.
The green aircraft is assembled at(IAI) in Tel Aviv, fitted with a ferry package and flown to Gulfstream's Dallas-Love Field facility for outfitting and painting. The G280's wing—derived from the G550 airfoil with a slightly different twist distribution and new large, wide radius winglets—has more sweep and 495 sq. ft. of area, 34% more than the G200 wing. Similar to G550, design cruise speed is Mach 0.80, up from Mach 0.75 for G200. That yields up to 29 more kt. true air speed (KTAS), enough to shave 30 min. or more off London-New York flight time.
The larger wing, along with the wing center section tank and feeders, also holds 20% more fuel than the G200's, enabling Gulfstream to shrink the forward belly tank and eliminate the 5,515-lb.-capacity, 67-cu.-ft. fuselage tank, replacing it with a 1,130-lb.-capacity aft belly tank. Overall fuel capacity actually is 390 lb. less than the G200's, but the more-efficient wing and new engines make up for the difference.
The G280's T-tail empennage features larger area fin and stabilizers to handle the aircraft's nearly 2-ton weight increase.
The flight-control system of the new aircraft has little in common with that of G200 other than similar pitch-control mechanisms and the stall-protection system. The roll-control system, for example, uses manually actuated ailerons with servo tabs that provide high-fidelity aerodynamic feel. Computer-controlled multi-function spoilers provide most of the muscle needed for roll control. The result is natural feel, abundant roll-control authority and well-harmonized pitch and roll forces at the yoke.
G280 is fitted with a fly-wire-wire (FBW) rudder in place of the manually actuated, boost-assisted system on the G200.
In keeping with long-standing Gulfstream design practice, G280 has no leading edge high-lift devices. The trailing edge flaps are electrically controlled and hydraulically actuated.
The aircraft boasts an updated, fully split buss electrical system with increased automatic load shedding compared to G200's hybrid split/parallel buss architecture that shares common emergency and hot battery busses. Aboard G280, there are left and right 28-volt-direct-current (VDC) 400A brushless generators, plus a 28-VDC 400A auxiliary power unit (APU) starter-generator rated for inflight use up to 40,000 ft. at reduced output. Left- and right-side 24 VDC 38AH heated lead-acid batteries, plus a standby battery, are standard.
The hydraulic system has been updated to provide additional redundancy for the FBW rudder. The left and right sides have both engine-driven and electrically powered hydraulic pumps, similar to Challenger 300. The design provides the necessary power redundancy for the digital FBW rudder.
The G280 has a new brake-by-wire system with an auto-braking function, a first for this class of business aircraft. The auto-braking system has low, medium and high deceleration levels, plus a rejected takeoff off mode for maximum braking.
The ice protection system has been changed significantly. Gone are the G200's pneumatic de-ice boots on the leading edges of the wing and horizontal stabilizer. G280 uses a bleed-air for heated wing anti-ice.
Pro Line Fusion avionics provide the backbone of G280's PlaneView cockpit. The main instrument panel features three 15-in. screens with cursor control devices on the left- and right-side ledges and left and right standby multifunction controllers [SMCs] in the glareshield panel. Gulfstream invented the SMCs to provide each pilot with a full-function electronic standby instrument system that doubles as a display and test control box. The 3 X 4-in. full-color LCD screens are in direct, head-up view of each flight crewmember.
Two multifunction control display units in the center console provide a flight management system (FMS), radio tuning and other functions. The throttle quadrant assembly that sends electronic commands to the engine Fadecs has servos that move the throttles in response to auto-throttle commands.
Other standard features include triple VHF comm and dual nav radios, dual distance measuring equipment, dual combined Mode S/Traffic Alert and Collision Avoidance System (TCAS) transceivers, dual FMS with 12-channel wide-area-augmentation/satellite-based-augmentation-system GPS receivers, dual digital air computers and dual solid-state attitude-heading reference systems, along with a single Multiscan weather radar, automatic direction finder receiver, HF transceiver, triple-frequency emergency locator transmitter, radio altimeter, 120-min. cockpit-voice/flight-data recorders and a terrain awareness and warning system (TAWS). A VHF comm radio is data-link capable for air traffic control functions such as Europe's Link 2000.
The passenger seating area is 17 in. longer than the G200's because the fuselage fuel tank has been removed.
Buyers have a choice of interior configurations with standardized floor plans, cabinetry, cabin sidewalls and systems. Eight-, nine- and 10-passenger configurations are available, each having a forward four-seat club section.
About half the buyers opted for an aft section with two facing chairs on the right side with a 6.7-ft.-long, three-place divan on the left. Others selected a four-place conference grouping on the left side of the aft cabin with the three-place divan on the right. The life raft is stored underneath the divan.
All seat pairs fold into berths. The divan may be extended into the aisle to form a 31-in.-wide berth. The aircraft can sleep four on extended flights in fully or near-flat berths.
The cabin management system is designed to use off-the-shelf iPod Touch personal digital assistants (PDA), loaded with a company supplied app, as the remote control. Two iPod Touch PDAs are included with the aircraft. The master seat has an iPod Touch docking station for charging as well as an Iridium satellite phone communications handset.
The cabin audio/visual system offers dual 160-gigabyte media servers that each can store 80-100 high-definition movies. There also are laptop ports for inflight business presentations.
Standard equipment includes a 19-in. forward bulkhead LCD monitor and a proprietary moving map system with flight information, high-resolution satellite imagery, geographic borders and passenger briefing videos.
Belt into the left seat of G280, as we did recently, and it is immediately clear that the Plane-View280 flight deck puts this aircraft on par with the best of Gulfstream's large-cabin aircraft. Brian Dickerson, the company's senior production test pilot, was in the right seat and Bob Wilson, midsize Gulfstream aircraft experimental test pilot, rode along as safety pilot.
Dickerson explained that G280 is the only aircraft in this class to have both full-authority auto throttles and an auto-braking system. It is also the only super midsize aircraft in current production to offer an optional head-up display and an enhanced vision system, although these were not installed on the demonstrator.
Dickerson and Wilson prepped the aircraft and they had the APU running when we arrived at Gulfstream's ramp at its Dallas-Love Field facility (elev. 487 ft.). Outside, the temperature was 33C/91F; inside the aircraft it was 70F.
Pre-start checks were straightforward, using the standby multifunction controller to run through stall warning, TCAS and TAWS tests, plus setting the landing field elevation. The FMS performance database was 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 (one-engine-inoperative) 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.
Rolling out of the chocks, we found the nosewheel steering and new brake-by-wire system to be smooth and precise.
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 just under 7,400 lb. of thrust on each engine. With a weight-to-thrust ratio of 2.16:1, 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 changes cause 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 is 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 westward from Dallas-Love to Flight Level (FL) 450 in 21 min., including a 3-min. ATC delay. That is impressive as the outside air temperatures (OAT) were mostly ISA (international standard atmosphere)+15-17C until we climbed above FL300. At FL450, 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 FL450 at ISA-5-6C. At a weight of 30,800 lb., fuel burn was 1,510 lb. per hr. (pph) at normal cruise and 1,810 pph at HSC. The flight manual 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, it predicts 1,778 pph at that weight and OAT.
The aircraft was buffet-free up to a 40-deg. angle of bank, corresponding to 1.3g. At maximum takeoff weight, the aircraft has 1.2g of buffet margin from Mach 0.75-0.80 at FL450. 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 is unlikely to disturb passengers.
When level at low altitude, we flew a couple of steep turns. It is easy to maintain altitude using the primary flight display's flight path marker and airspeed trend vector. Pitch force is moderately heavy, thereby preventing over control. Roll response, with the help of the fly-by-wire roll spoilers, is crisp, but roll effort is moderate, again preventing over control.
Dickerson next demonstrated the 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 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 stickpusher at weights of 30,150-30,250 lb. For the three configurations, stall warning stickshaker then stall prevention stickpusher, 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 instrument landing system approach. Wilson pegged Vref at 128 KIAS for the aircraft's estimated 29,600-lb. landing weight, providing a 23% margin over stall. The auto braking system was set 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/Kreuger flaps provide considerably more ground effect cushioning than in the G200. We floated down the runway for a few hundred extra feet before touching down. The auto-braking action was very smooth and progressive, and the aircraft slowed to moderate taxi speed in about 2,500 ft.
To sample 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.
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 the HTF7250 turbofans, thus speed was easily controlled. That's a vivid contrast to the throttle response of the G200's PW306As.
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 over 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 easily stopped the aircraft in the first 3,800 ft. of runway.
Conclusions? G280 delivers sporty performance, excellent handling qualities and unsurpassed avionics capabilities in this class of business aircraft. Meanwhile, its range and speed capabilities are on a par with far more expensive large-cabin aircraft.
|Wing Loading||80.0 lb./sq.ft.|
|Power Loading||2.60 lb./lbf.|
|Engines||2 Honeywell HTF7250G|
|OATºC||7,624 lb. each/ISA+16.7C|
|Payload With Max. Fuel||1,000/454|
|Fuel With Max. Payload||11,550/5,239|
|Fuel With Executive Payload||14,000/6,350|
|Time to FL 370 (min.)||14|
|FAR Part 25|
|OEI rate (fpm/mpm)||846/258|
|FAR Part 25|
|OEI gradient (ft./nm; m/km)||371/61|
|Sea Level Cabin||28,900/8,809|
|Certification||FAR Part 25 A1-120, 122|