Hawker Beechcraft is in the odd position of having two Hawker jets in its lineup that are many generations apart. The Hawker 4000 is a high-tech, super midsize jet with a carbon-fiber fuselage and the latest in system sophistication. The Hawker 900XP is the newest version of one of the very first business-jet designs. This Hawker has been in continuous production since 1962, longer than any other civilian jet. The only other airplane that comes close to such a long continuous-production run is the Boeing 737 that entered service in 1968.
Like the 737, the Hawker line has been stretched and had its wing modified, and is now powered by very advanced, efficient turbofan engines. The 900XP is little changed, except for the engines, from the previous 850XP, which grew winglets for better climb and improved range. New Honeywell TFE731-50R engines are so much better that all aspects of performance -- takeoff, climb, cruise speed, range -- are improved, with no addition of fuel capacity. And operating costs are reduced too.
Like other recently designed jets, the Hawker 4000 relies on multi-layered systems and sophisticated monitors to assure continued safety in the event of failures. But the 900XP is of a different era, when extra metal and manual backups for key systems governed design philosophy.
It's important to remember that the British were the first to have a viable civilian jet, the de Havilland Comet. The elegant Comet, with its engines buried in the wing roots, beat the Boeing 707 and Douglas DC-8 into airline service by several years in the 1950s.
But a series of in-flight airframe failures ended the Comet's lead as a jet airliner. The cause of the failures was eventually traced to metal fatigue, a phenomenon not well understood at the time. The higher levels of pressurization needed at jet altitudes, the different air loads and vibrations of jet flight, and a lack of understanding of how a fatigue crack could begin were all factors in the disasters. The entire global aviation industry learned important lessons from the Comet, but de Havilland learned the most.
Now put yourself in the shoes of the engineers at de Havilland who were tasked with designing a small jet intended to be used for personal transportation. The Hawker that we know today entered service as the Hawker-Siddeley 125, but the design originated at de Havilland before the companies merged under the Hawker name. The 125 number was a de Havilland design designation.
With the airframe failures of the Comet fresh in the minds of everyone at de Havilland, the level of conservatism when designing the 125 cannot be overstated. This airplane was designed to have an airframe that would never fail, and none has. It is approved for unpaved runways, even sod -- something very rare for a jet -- and Hawkers have survived both a ground-launched missile strike over Africa and a collision with a glider over the western United States. The crews of both airplanes landed without injury to passengers, though the captain of the Hawker that collided with the glider was injured when the glider's wing smashed into the nose of the jet.
When you look at a Hawker of any vintage, you can see this extra strength. The airplane weighs more than the minimum requirement, I'm sure, but there is enough useful load to fill the tanks and fill the seats, which is not the norm in other airplanes.
The systems are equally basic and robust. You don't need the hydraulics or electrics to carry on in the Hawker. There are system redundancy and backups, to be sure, but if your worst day happens, the Hawker will get you back to a runway.
The first several versions of the Hawker were powered by Rolls-Royce Viper turbojet engines. The Viper was a reliable but very loud and fuel-thirsty engine. And it didn't recover oil from all bearings in the engine, so oil consumption was high and copilots were tasked with pouring more oil in before every trip.
The airplane evolved into the 600, with a much longer cabin than the original, and with more fuel capacity for longer range. But the really big change came in 1976, when a refined version of the 600 was equipped with a Garrett -- now Honeywell -- TFE731 turbofan engines, and the airplane was renamed the 125-700. It was, along with the Learjet 35 and Falcon 10, one of the first applications of a turbofan in business jets. The 731 engine burned about half the fuel in cruise of the Viper, and range jumped accordingly.
In 1983 the wing was modified with a new shape and longer span, and the canopy was redesigned with wraparound windshields and a lower drag shape to create the 800. The Hawker had been a sales success, but it was the 800 that vaulted the airplane into the lead in the midsize-jet segment.
Though the Hawker traces its design roots back about 50 years, the Pro Line 21 avionics system, with its flat glass displays and full capability flight management systems, is on par with the most recently designed midsize jets. And the cabin materials and furnishings are top-notch, offering the comfort that has been key to keeping the airplane in production for so many decades.
