Four years after the announcement of the Astra IV, Aircraft Co. (now .) unveiled the $14.5 million Hawker Horizon, a revolutionary new composite fuselage/aluminum wing aircraft, at the 1996 NBAA Convention. The new Hawker would “retain the [legacy] Hawker’s classic look and feel,” but would offer large-cabin aircraft class avionics and systems, a high-speed, super-critical airfoil and a thorough aerodynamic clean-up.
Raytheon positioned the Horizon as a step-up product from the legacy Hawkers. It could fly considerably higher, faster and farther than any British-designed Hawker, plus it would have much improved hot-and-high takeoff performance.
Maximum range was set at 3,400 nm at Mach 0.78 and Raytheon guaranteed the airplane would be able to fly 3,100 nm at Mach 0.82, assuring the aircraft would have transcontinental U.S. range against virtually any probable headwind.
The overall 7.0-ft. outside diameter of the fuselage would be virtually the same as the all-aluminum legacy Hawker 125 series, but the more structurally efficient, sandwich construction composite fuselage tube would increase maximum cabin height to 6.0 ft. and width to 6.5 ft. Overall cabin volume would be 60% greater than that of the Hawker 800XP, which was the large-cabin midsize aircraft at the time. This would make room for two full seating areas. The Hawker Horizon also would have a flat floor, inflight access to the aft baggage compartment, a full-service forward galley and a full-width aft lavatory, all much-desired design features in the super-midsize class.
H. Sam Bruner, a prime architect of the GIV and lead engineer on the Hawker Horizon, embraced large-cabin aircraft design standards for the new aircraft. The Horizon would have long-life, low maintenance, brushless AC generators powering TRUs that supplied a split bus DC electrical system, dualLaseref IRS boxes, dual air cycle machines, bleed air wing anti-ice, along with fly-by-wire rudder and spoileron controls, plus a best-in-class 6,000-ft. maximum cabin altitude. It also would be the launch platform for Honeywell’s new Primus Epic flat-panel avionics system and it would be the first aircraft in class to have full-authority autothrottles, vertical navigation and an integrated performance computer.
Bruner wanted the Horizon to offer a legacy Gulfstream’s sporty performance. Similar to the GIV, it would have a generously sized 531-sq.-ft. wing and ample engine thrust to assure margin for weight growth. The original estimated maximum takeoff weight was 36,000 lb and each PW308A turbofan engine was to be rated at 6,500 lb. Estimated standard-day takeoff distance was 5,250 ft.
Raytheon boldly predicted first flight would occur in late 1999, with type certification and initial customer deliveries to commence in second quarter 2001. But the development program became mired in difficulties and composite fuselage manufacturing was plagued by process control hiccups. Some at Raytheon wondered if the Horizon program was too ambitious for the capabilities of its legacy engineering department in Wichita.
Initialtype certification finally occurred in November 2006. Along the way, Raytheon renamed the aircraft Hawker 4000. The program continued to stumble along with numerous post-certification IOUs due customers. Only a dozen production aircraft were delivered before 2009. certification wasn’t received until May 2010.
On balance, though, the Hawker 4000 is maturing into a strong player in the super-midsize league. Bruner’s foresight in providing plenty of wing and engine margins proved critical. When the empty weight of the aircraft ballooned by 2,700 lb, MTOW was bumped up to 39,500 lb and they asked P&WC to crank up engine thrust to 6,900 lb. There was ample wing and thrust to compensate for the weight gain. Actual takeoff distance decreased to 5,068 ft.
But the extra bulk did cause range performance to suffer by 300 nm. With eight passengers, the Hawker 4000 can fly just over 3,100 nm at Mach 0.80. However, it’s still the only currently certified super-midsize aircraft that can carry seven passengers with full fuel.
Hawker Beechcraft has delivered fewer than 60 Hawker 4000 aircraft in the past four years. In an attempt to stimulate sales, it’s holding down the price to $22 million, a bargain considering this aircraft’s capabilities and systems sophistication.