DEVELOPMENT OF THE Canadair Regional Jet Series 700 promises to be less difficult than launching the 70-seat aircraft, jokes John Holding, group executive vice-president, engineering and product development, at Bombardier Aerospace. Certainly, the Canadian company has been talking about stretching its 50-seat Canadair Regional Jet (CRJ) for almost as long as it has been building the aircraft.

The launch finally came in January with, it emerges, a mere four firm orders from French regional Brit'Air. Including conditional orders, options and memoranda of understanding, commitments for the CRJ-700 now stand at 67, but backlog is not Bombardier's immediate concern. The Canadian company has launched the 70-seater because it needs to offer its CRJ customers a family of aircraft.

It is the company's responsibility to ensure that customer airlines have a larger aircraft to cater for growth, says Bombardier Regional Aircraft division president Pierre Lortie. He describes the CRJ-700 as a "natural extension" of the company's regional-aircraft line, which also includes de Havilland Dash 8 turboprops seating from 30 to 70 passengers.

Natural it may be, but the company had to work hard to convince Bombardier's board to launch the stretched CRJ, particularly after it approved development of the 70-seat Dash 8-400 in June 1995 with a similarly slim orderbook. Key to both decisions is Bombardier's belief that distinct markets exist for the two aircraft - an argument given some credence by the fact that Dash 8-400 launch customer Great China Airlines of Taiwan has also signed a memorandum of understanding to buy CRJ-700s.

Bombardier forecasts almost equal market potential for both 70-seaters, estimating that the 60- to 90-seat short-range (turboprop) and long-range (jet) markets will each account for almost 25% of the 8,000 regional-aircraft deliveries it is projecting for the period 1996-2015. That equates to a potential market for the $23 million CRJ-700 of some 2,000 aircraft, and compares with protected deliveries of some 1,100 aircraft in the 40- to 59-seat long-range market served by the $20 million CRJ-200.



Design of the stretched CRJ-X began in 1994, and the configuration is effectively frozen, says Holding, although windtunnel testing continues to fine-tune the landing configuration and to confirm loads for drawing release. During the current joint-definition phase, started in February, some 500 people from Bombardier and its risk-sharing partners will work together in Montreal to freeze the interfaces between their parts of the aircraft before returning home to begin detail design.

Joint definition will be a key element in the success of the programme, Holding says. The process was pioneered on the Global Express business jet and refined on the Dash 8-400. While its partners are providing almost one-third of the CRJ-700's C$645 million ($478 million) development cost, Bombardier retains overall design authority, is responsible for technical management and systems integration, final assembly, certification, sales and support.

Although joint definition will continue until November, detail design will get under way in July as structural and systems interfaces are finalised. Canadair will build the cockpit section and wing, while Bombardier sister company Shorts will produce the fuselage barrel. Mitsubishi has been selected to provide the aft fuselage, and negotiations continue with potential risk-sharing suppliers of the tail section.

Although the aircraft is derived from today's CRJ, itself a derivative of Canadair's Challenger business jet, there is little structural commonality between the 50- and 70-seater, admits Holding. The fuselage has the same cross-section, but the floor has been dropped by 50mm and the windows raised 140mm to reduce the "tunnel effect" when entering the cabin, and to improve the field of view when seated - a criticism of the current CRJ. The CRJ-700 seats 70 four-abreast, with 790mm pitch (1.04m at the overwing-exit row), but can seat between 66 and 78 for different markets.

While the fuselage has been stretched 4.72m, the cabin has actually been extended further, he says, by moving the aft pressure-bulkhead back - made possible by relocating the auxiliary power-unit to the tailcone, where it is accessible through clamshell doors. Bombardier has taken advantage of the stretch by locating an underfloor baggage-bay, for gate-checked luggage, in the forward-fuselage plug.

Wingspan has been increased 1.83m by inserting a root plug, which houses additional fuel and the longer landing gear. Leading-edge high-lift devices are added to provide field performance similar to that of the current CRJ; take-off performance is significantly better, says Holding. Range and speed performance is similar to that of the CRJ-200, enabling operators of both to match aircraft capacity to demand without losing the flexibility and economy of common crew-qualification, he says.

The current CRJ's Rockwell-Collins Pro Line 4 avionics are retained. Avoiding flightdeck changes allows a common pilot pool and the differences training required will be limited to one simulator session, Bombardier believes. Beyond training, commonality extends to maintenance, spares and support, which account for the bulk of fleet costs, he argues.



General Electric is responsible for the complete powerplant, as a risk-sharing partner, with Shorts supplying the nacelle and thrust-reverser to GE. The 56kN (12,670lb)-thrust CF34-8C1 is a 50% growth version of the engine powering the current CRJ, and introduces full-authority digital engine-control. Other design changes include a common left/right nacelle, with clamshell cowls to improve accessibility - a criticism of the current CRJ.

Systems design is based on that of the existing aircraft, but with supplier partners responsible for providing integrated systems. Leibherr-Aerospace is developing the air-management system, covering ice protection, avionics cooling and cabin pressurisation; Sundstrand,the electrical-generation and slats/flaps-control systems; Menasco, the main and nose landing-gear complete with braking and steering systems; and Intertechnique, the fuel system.



Bombardier plans to fly the first of four test aircraft in the second quarter of 1999, and is aiming for simultaneous Canadian, European and US certification and first deliveries in the fourth quarter of 2000. The CRJ-700 will be approved under an amended CRJ type certificate, which is itself an amendment of the original Challenger ticket. Holding says the CRJ-X will be certificated to the latest requirements where there are design changes from the current aircraft.

Holding says that the larger aircraft, with its 20% lower seat-kilometre direct operating-costs, will allow regional airlines to grow by replacing existing major-airline jet services and by increasing frequency in existing jet-airliner markets - a trend Bombardier has observed already among current CRJ operators, where replacing or supplementing major-airline jet service accounts for almost 50% of operations.

As Bombardier Aerospace president Bob Brown says: "We have proved that the market for regional jets exists, and it is a major area for growth. Now that the momentum is building, the CRJ-700 makes sense."

Source: Flight International