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Aviation History
1997
1997 - 2292.PDF
CORPORATE AVIATION Global Express 9004 has been painted, ready for its NBAA debut 1998. A further 60 will be delivered in 1998-9. Holding says that Bombardier has held on to its Learjet 45 customers "...by being honest with them". The company has orders for some 130 Learjet 45s, including 25 for the Flexjet fractional-ownership programme operated by Bombardier Business JetSolutions. Shares in "four or five" aircraft have already been sold, and the Learjet 45 promises to be a "good prod uct" for the Flexjet scheme, he believes. BREAKING NEW GROUND Assessing the Learjet 45 programme, Holding says: "At the end of the day, the concept was right, the basic design was right. Bringing it together and certificating it was difficult." He believes that the programme "...has broken new ground" by being the first to involve con current US Federal Aviation Administration and European Joint Aviation Authorities QAA) certification of a business jet - JAA approval is expected soon after that of the FAA. Concurrent FAA and JAA certification is also a key goal of the Global Express programme. Holding seems relaxed about progress with Global Express flight testing, despite the third aircraft having been grounded for six weeks for repairs following an inadvertent wheels-up landing. "We're about four to six weeks behind where I'd like to be, but there are no real con cerns overall," he says. One reason for his confidence is the progress made using the first two aircraft; another is the imminent first flight of a fourth Global Express, which will join the Wichita-based test fleet in late September. Aircraft 9001, assigned to performance and handling flight-tests, has been used for stall, sta bility and flutter evaluation - all of particular concern, Holding admits, because of the Global Express' highly swept, high-speed, wing with its complex high-lift devices. "There was some concern about our high-speed wing, but we designed it to have very good low-speed charac teristics. It's very pilot-friendly," he says. "The aircraft has demonstrated good natural stall," Holding says, adding that handling qual ities during stalls are "superb". Stall speeds equal the company's best estimates and stall characteristics meet or exceed predictions; there has been "excellent" correlation between computational fluid-dynamics analysis, wind- tunnel testing and flight, he says. Low approach speeds have been confirmed - reference speed (VnFF) is 125kt at maximum landing weight - and preliminary flight testing has shown that take-off performance meets predictions. Brake testing to determine the landing performance will begin in September. Learjet 45s line up for post-certification modifications before delivery In-flight handling characteristics are "excel lent". Dutch roll is controllable throughout the flight envelope with yaw dampers off, Holding says. Flutter testing has been completed out to 398kt and Mach 0.95. Buffet onset during manoeuvres at high speed and altitude has shown good correlation with predictions, "...confirming the superior manoeuvre mar gin". A bank angle of 5 3 ° can be attained before buffet onset at M0.8 and 51,000ft, he says. Aircraft 9002 is assigned to systems evalua tion, and early tests have involved the brakes, landing gear, auxiliary power-unit (APU), engines and avionics. Overall brake perfor mance is "exceptional", says Holding, and assessment of the brake-by-wire system has been completed. Landing-gear testing has included successful in-flight extension and retraction after a prolonged high-altitude cold soak. The APU has been operated up to 45,000ft and start ed up to 37,OOOft, meeting the specification. Holding says that all results to date from the BMW Rolls-Royce BR710 turbofans "...have met or exceeded expectations". The engines will be overweight when the Global Express enters service, but a plan has been proposed to achieve the guaranteed weight. The aircraft weight guarantee will be met and, even with overweight engines, there will be "no problem" meeting the performance guarantees, he says. Bombardier may certificate the Global Express with a 22 5kg higher maximum take-off weight, he reveals, to give the operator more flexibility. TESTING THE RANGE Tests to confirm the Global Express' quoted 12,400km range have still to be conducted. Aircraft 9003 and 9004 will be used, because 9001 and 9002 have instrumentation which increases drag. "We have enough data already to know that we will meet our commitments," Holding says. He hopes to have completed a good range test before the National Business Aviation Association show at Dallas, Texas, on 23-25 September, where 9004 will be displayed. Aircraft 9004 has been outfitted with an inte rior at the Global Express final-assembly plant at de Havilland in Toronto. Holding says that the aim has been to demonstrate what can be achieved within the aircraft's 2,700kg comple tion allowance. Beginning with Global Express 9005, now in final assembly, aircraft will be outfitted and painted at Bombardier's new com pletion centre, now under construction in Montreal. Aircraft 9005 is to arrive there in November, and the centre will be able to accommodate up to 14 Global Expresses at a time and complete 30 business jets a year. The Global Express is due to enter service in June 1998, but much testing remains to be done. Holding is confident that the certification date will be met, and that there is flexibility in the programme. Aircraft 9004, for example, is as signed to function and reliability testing in early 1998, but will be available from September for other flight testing, he says. • 32 FLIGHT INTERNATIONAL 10 - 16 September 1997
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