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.
The G280's cabin is 17-in. longer than that of the G200 because the fuselage fuel tank has been removed. The extra cabin length makes available 8 in. more seating room in the main area and a 9-in. larger aft lavatory. The finished cabin is 6.1-ft. high, 6.9-ft. wide, with a 5.4-ft.-wide floor, and is 25.9-ft. long. Each side of the main seating area now has two extra windows and the lavatory has a window on each side. Variable hue LED wash lighting and aisle lighting are standard, along with several passenger reading and work surface lights.
Buyers are offered a choice of Gulfstream Select interior configurations with standardized floor plans, cabinetry, cabin sidewalls and cabin systems. All factory standard configurations incorporate Gulfstream's Cabin Essential redundant cabin management system. All aircraft come equipped with electronic and paper copies of Gulfstream's cabin operating manual, a maintenance handbook and instruction video.
Configurations are available to accommodate eight to 10 passengers, each design having a forward four-seat club section. Individual chairs are 25-in. wide with 21 in. of seat room between the armrests. Each seat has a telescoping headrest with optional foldout “wings” to support the sides of the head.
About 10% of buyers are opting for a second four-seat club section in the aft cabin. Close to 45% are choosing an aft section with two facing chairs on the right side with a 6.7-ft. long, three-place divan on the left side. The remaining buyers are selecting a four-place conference grouping on the left side of the aft cabin with the three-place divan on the right side. Customers said they wanted life-raft storage underneath the divan, so that feature is built into the aircraft.