There's a new super-midsize champ.
Nearly Clean Screen Design
The G280 has new CAA Israel and Part 25 type certificates, ones that are not linked to a previous model. The aircraft complies with Part 25 through Amendment A1-120, plus A122. CS-25 A2 type certification is in the works. The aircraft meets ICAO Annex 16 and FAR Part 36 Stage 4 noise standards, along with FAR Part 34 fuel venting and exhaust emission requirements.
The TCs and other approvals are, or will be, owned byLP, a joint venture of Gulfstream Aerospace and Ltd. based at Tel Aviv-Ben Gurion Airport. The green aircraft is assembled at IAI using parts made in the U.S., Israel and other countries in accordance with a CAA Israel production certificate. It's then fitted with a ferry package and flown to Gulfstream's Dallas-Love Field facility for painting and outfitting.
The G280's design is classic Gulfstream, one for which the engineers in Savannah provided ample margin for weight gain during the development process. They fitted it with a generously sized wing and empennage, along with powerful engines. The G280 has sporty performance in spite of its nearly 4,000-lb. weight increase compared to the G200.
That wasn't the case for IAI's G200. It fell well short of performance goals because the Israelis set overly ambitious weight goals, specifying an 18,100-lb. BOW and 33,450-lb. MTOW. The original design indeed was even more anemic than the final product. IAI planned to use 5,900-lb.-thrust engines, as we reported in December 1993.
The aircraft's BOW later ballooned to 20,200 lb., fuel capacity was increased and MTOW was bumped to 35,650 lb. The 369-sq.-ft. modified Astra SP wing and 6,040-lb. increased thrust Pratt & Whitney Canada PW306A engines simply couldn't handle the increased heft. The added weight gave it one of the highest wing loadings and weakest thrust-to-weight ratios of any purpose-built business jet.
Gulfstream fixed those problems for the G280 starting with a clean-sheet wing derived from the G550 airfoil with a slightly different twist distribution and new large, wide radius winglets. It has more sweep and 495 sq. ft. of area, 34% more than the G200 wing. While it has less than half of the G550's wing, the G280 has nearly identical wing loading because of its lower weight. Similar to the G550, design cruise speed is Mach 0.80, up from Mach 0.75 for the G200. That yields up to 29 KTAS more speed, enough to shave half an hour or more off the flight time between London and New York.
The larger wing, along with the wing center section tank and feeders, also holds 20% more fuel than the G200's wing and center tanks. The increased fuel capacity in the wing tanks enabled Gulfstream to shrink the size of 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 was reduced by 390 lb. from the G200, but the more-efficient wing and new engines more than made up the difference. Range with four passengers is boosted nearly 300 nm even though long-range cruise is 29 KTAS faster. Gulfstream selected second-generation 7,624-lb.-thrustAS907-2-1G turbofans, marketed as HTF7250G engines, to replace the P&WC powerplants on the G200. The Honeywell engines give the G280 the best thrust-to-weight ratio of any Gulfstream in current production.
Similar to Savannah-built Gulfstreams, the G280 also gets a new T-tail empennage that replaces the G200's cruciform tail. The vertical and horizontal stabilizers have more area to handle the aircraft's nearly two-ton weight increase. The horizontal stab also has more sweep.
The new aircraft retains fuselage outer loft contours, but the G200's all metal, semi-monocoque structure was modified to handle increased pressurization, the new wing, additional windows and aft internal baggage bay access door. In addition, the external baggage door was changed to a plug design that opens inward. The main entry door is virtually the same as the one on the G200, but it's now hydraulically retracted rather than using air springs.
The increase in pressurization to 9.2 psi from 8.9 psi results in a 1,000-ft. reduction in maximum cabin altitude. Passengers, however, will on average experience slightly higher cabin altitudes because the aircraft can climb directly to FL 430 or higher, resulting in a 6,500-ft. cabin altitude. The G200 could barely reach FL 390 at MTOW, where cabin altitude is 6,000 ft.
The flight control system of the new aircraft has little in common with that of the 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 a high fidelity aerodynamic feel. Computer controlled multifunction 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.
The G280 is fitted with a fly-wire-wire (FBW) rudder in place of the manually actuated, boost-assisted system installed on the G200. The rudder pedals have no mechanical connection to the rudder. Instead, the pedals have movement transducers that send electrical signals to two, dual-channel digital FBW computers. Each computer then commands a separate FBW electrohydraulic rudder servo actuator, powered by the left or right hydraulic system.
The avionics system also sends signals to the FBW computer for rudder bias in the event of asymmetric thrust, yaw damping and turn coordination. In the event of an engine failure, the rudder bias system is so effective that it virtually eliminates any sideslip. Since the rudder pedals aren't connected to rudder linkages, they wouldn't provide pilots tactile feedback of an engine-out condition without an add-on system. The G280 is fitted with a rudder feel servo system that mildly deflects the rudder pedals in proportion to thrust asymmetry, thus providing artificial feel that “talks to your toes” during an engine-out condition.
In keeping with long-standing Gulfstream design practices, the G280 has no leading-edge high-lift devices. The trailing-edge flaps are electrically controlled and hydraulically actuated. The G200's relatively small wing, in contrast, needs flaps and leading-edge slats and Krueger flaps to boost lift for takeoff and landing.
The G280 has a thoroughly updated and fully split bus electrical system with increased automatic load shedding compared to the G200's hybrid split/parallel bus architecture that shares common emergency and hot battery buses. Aboard the G280, there are left and right 28-VDC 400A brushless generators, plus a 28-VDC 400A 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. Similar to the G200, the right battery is used to start the APU. But the engines use air turbine starters, so the G280 doesn't need the G200's big batteries, which can be used for electric starting of its main propulsion engines.
The hydraulic system also has been updated, mainly to provide additional redundancy for the FBW rudder. The left and right sides have both engine-driven and electrically powered hydraulic pumps, similar to the Challenger 300. The design provides the necessary power redundancy for the digital FBW rudder.
As with the G200, the right side powers the landing gear, nosewheel steering, Q-feel system for the elevators and on-side thrust reverser. The stall prevention stick pusher function now is incorporated into the autopilot pitch servo. The left-side system powers the ground spoilers as in the G200, but now it also powers the entry door retraction system and wing flaps. Both sides power the brake-by-wire system, multifunction spoilers and elevators.
The G280's air-conditioning and pressurization system is similar to that of its predecessor, but the single air-cycle machine pack has been modified to improve refrigeration performance. The APU now is approved as essential equipment. It's certified for unattended operations and it can be used on takeoff and up to 20,000 ft. for pressurization and air-conditioning.
The basic G200 landing gear set is retained, including virtually identical nose gear and nosewheel steering. The beefier trailing link main landing gear handles the G280's higher weights. The aircraft gets 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 mode for maximum braking.
The ice protection system has been changed significantly. Gone are the G200's pneumatic deice boots on the leading edges of the wing and horizontal stabilizer. The G280 uses bleed air for heated wing anti-ice. Similar to most other turbofan aircraft with horizontal T-tails, the stabilizer doesn't have ice protection. As aboard the G200, engine bleed air is used to heat the engine inlets for anti-ice protection and electrical heaters protect the windshields, probes and static ports.