GRAHAM WARWICK / WASHINGTON DC
Bombardier's new business jet has been designed to fill a niche in the super mid-size range and dominate a market for an expected 1,300 aircraft over 10 years
With a line-up ranging from the light Learjet 31A to the long-range Global Express, Bombardier had the luxury of designing its newest business jet to fill a specific niche in its product portfolio. As a result, everything about the aircraft is optimised around the US coast-to-coast mission, even its name - Continental.
The niche the Canadian company identified was in the emerging super mid-size market, filling the gap in price and performance between its mid-size Learjet 60 and large Challenger 604.
With the Continental, the company aims to dominate a market expected to total almost 1,300 aircraft over 10 years.
The Continental is the product of the most extensive market research Bombardier has ever undertaken, says executive vice-president, engineering and product development, John Holding. The two-year process began in 1996 with a survey of chief executives to identify what they liked and disliked about current aircraft. This isolated the real drivers of value in the mid-size market and shaped the Continental.
The resulting aircraft is relentlessly conventional in its design and ruthlessly optimised for its mission. "We had a very specific target - to fill a gap in our product line," says Continental product director Claude Chidiac. "We were very clear about what we wanted to do with this aircraft. It's aimed squarely at the continental mission."
The Continental is also designed to a price point - under $15 million at 1998 prices. "Super mid-size aircraft are becoming more expensive. There is a need for a true transcontinental aircraft that will not break the bank," says Chidiac. Existing super mid-size jets cost $18.6-18.8 million, while the Continental's closest competitor, Raytheon's Hawker Horizon, costs $16.9 million but is promoted as an intercontinental aircraft.
"There was much more design-to-cost discipline," says Holding. "We established the price the market can bear, which drove us to design for a cost at which we can still make a profit. It's a challenging price, but we have achieved it without compromising the quality of the aircraft." Such cost considerations may be relatively new to business aviation, but Bombardier faces similar price pressures in its regional aircraft, he says.
The aircraft is also designed for low operating costs. "In other business aircraft, DOCs [direct operating costs] turn out what they are. We specifically looked at life-cycle costs," says Holding. This was achieved by keeping the aircraft simple, carefully selecting components and working closely with risk-sharing partners. The maintenance service plan available with the new HoneywellAS907 engine is a major contributor to the Continental's competitive DOCs.
Fractional influences
"DOCs are key to fractional ownership," says Chidiac. Fractionals achieve much higher utilisation rates than traditional business jet operators and experience from Bombardier's Flexjet programme strongly influenced the Continental's design. The first four or five production aircraft are destined for Flexjet, Holding says, where they will accumulate hours quickly and lead the fleet in uncovering any early issues.
Designing for the continental mission has resulted in an aircraft with a 5,700km (3,100nm) range, able to carry eight passengers coast-to-coast across the USA at Mach 0.8 against the strongest winds.
At the same time, balanced field length is under 1,530m (5,000ft), thereby providing access to smaller airports, while initial cruise altitude is 41,000ft (12,500m) and maximum cruise altitude 45,000ft, allowing the aircraft to climb quickly above crowded airspace.
The cabin is among the largest in its class, 2.18m wide and 1.85m high (86in and 76in, respectively) with a flat floor large enough to provide double club seating for eight passengers, a forward galley and an aft toilet and baggage compartment. The drag of the widebody cross-section is offset by area-ruling of the aft fuselage. Although acknowledging that speed is important for large business jets, Holding believes M0.8-0.82 is sufficient for the Continental's shorter missions.
An all-metal airframe avoids the potential certification and ownership risks Bombardier sees in the composite fuselage of Raytheon's Hawker Horizon. "We made a key decision not to experiment with new technology, so we have a conventional metal airframe," says Chidiac. Holding agrees: "Price and time to market were very sensitive, so we did not experiment with technology." He believes Raytheon runs the risk of further delays to the Horizon.
The all-metal wing has a supercritical section and winglets, the latest iteration of technology pioneered on the original Challenger. The wing area, at 48.5m² (522ft²), is larger than that of the Challenger, to give the required short-field performance without the complexity of leading-edge flaps and with a single trailing-edge Fowler flap per side. All fuel is contained in the wing, for simplicity and safety.
Simplicity also drove the systems philosophy. "We tried to keep it simple and think cost," says Holding. "We looked at what the end customer saw as value and did not add the cost and complexity of systems that were nice to have, but did not add to the mission. This aircraft is designed to do a specific mission very economically."
The electrical system is DC, with 400A brushless generators on the engines and a tail-mounted auxiliary power unit allowing for dispatch with any one generator failed. The fuel system uses motive flow pumps with backup brushless DC motor pumps for increased reliability. The two 207 bar (3,000lb/in²) hydraulic systems each have an engine-driven pump and a DC motor pump for improved redundancy.
Primary flight controls are a mix of manual and powered. Ailerons are manually activated via cable, while the elevators and single rudder panel are hydraulically powered by both systems with manual reversion. A single yaw damper is installed and there are two ground and two multifunction spoiler panels per side on the wing.
The cockpit uses the latest in avionics technology, but tailored to the continental mission. The Rockwell Collins Pro Line 21 integrated avionics suite features four large, 250 x 300mm (10 x 12in), liquid-crystal displays:a primary flight display and multifunction display for each pilot. Bombardier has elected not to incorporate cursor control devices and pull-down menus. "This is state of the art, rather than breaking new ground," says Chidiac.
The standard equipment list is tailored to the continental mission, and includes: enhanced ground proximity warning; traffic alert and collision avoidance; dual attitude heading reference systems and single global positioning sensor; and a single flight management system. The aircraft will be compliant with reduced vertical separation minima (RVSM) regulations at certification. "We have already mapped the skin waviness on the first aircraft, and it complies with the requirements for RVSM," says Holding.
While the Continental is optimised for the US coast-to-coast mission, the optional equipment list allows the operator to equip the aircraft for intercontinental flights. "We offer everything in the options needed to fly transatlantic, but it is not in the baseline aircraft," says Chidiac.
Options include a second FMS and GPS, and HF and satellite communications. There is no inertial reference system, but dual GPS will provide operators with the navigation performance required for North Atlantic flights, he says.
"We are developing the aircraft and a catalogue of options," says Chidiac. Provisions for the options that are expected to prove popular are already in the basic aircraft. "It's like the Learjet approach, everything is plug-and-play. The basic price includes everything for the intended mission. The options allow the customer to tailor the aircraft to a different mission."
Perhaps the biggest departure from Bombardier's low-risk approach to developing the Continental was the decision to adopt an all-new engine, driven by the operating economics. Designed for both the business and regional aircraft markets, the AS907 offered a low parts count, high reliability, good accessibility and simple maintainability. Honeywell is responsible for the complete integrated propulsion system, which includes the nacelle, engine build unit, air turbine starter, thrust reverser and mounts. Rated at 8,050lb thrust (36kN), the AS907 is derated to 6,500lb on the Continental to increase longevity. Design features include a low blade-count fan, integrally bladed compressor disks, low-emissions combustor and low-noise mixer exhaust.
Risk reduction
"What is attractive about the powerplant is that it is built with the operator in mind," says Holding, citing the accessibility for "on wing" maintenance. The fan module, or individual blades and composite stators, can be removed and replaced with the engine mounted on the aircraft, as can the accessory gearbox, mainshaft bearings and seals, low-pressure and high-pressure turbines and combustor. Individual fuel nozzles are replaceable on wing. Engine-mounted, the dual-channel full authority digital engine control (FADEC) provides optional trend monitoring. Maintenance is on-condition, and disks have 15,000-cycle design lives.
Honeywell has an extensive development and certification programme underway for the AS900 family, with 29 development engines manufactured and 15 currently in test. Over 8,300h out of more than 11,000h of testing planned by service entry have already been accumulated. The engine first flew in January on Honeywell's Boeing 720 testbed, and the AS977 version is in flight test on the BAE Systems Avro RJ-X regional airliner. To reduce risk, Bombardier asked Honeywell to conduct extensive testing of the integrated powerplant system before it flew on the Continental.
As a result a "totally representative" system - including nacelle, thrust-reverser, FADEC and throttle quadrant - has been flown on the 720. Overall, this saved time. "We would have had to do more testing on the ground if it had not flown on the 720," says Holding.
Earlier this year, Honeywell pushed back certification of the engine to build in design improvements that would typically have been incorporated post-certification. Bombardier, in turn, delayed the first flight of the Continental so that it could begin flying with certification-standard Block 2 engines incorporating these changes.
The real challenge in the Continental programme is not the technology in the aircraft, but the timescale for its development. Bombardier is aiming for certification 42 months after formal launch, its shortest timescale yet for an all-new aircraft.
To get a head start, the company pre-selected partners and brought them together for a nine-month joint conceptual design phase that concluded just before the formal programme launch in June 1999. A first for Bombardier, which previously begun working with partners during the joint definition phase following programme launch, joint conceptual definition proved to be a better way to work, says Holding.
"It allowed the partners to contribute more, to find better ways to do things outside of detailed specifications. There was more willingness to do trade-offs, more flexibility and a fuller understanding of what they were committed to. It was very beneficial to overall programme risk."
Provided they were prepared to sign up to the technical and commercial commitments required, the pre-selected companies were invited to join the programme as risk-sharing partners. Holding says some smaller players changed, but the major suppliers stayed on. These include Japan's Mitsubishi Heavy Industries (wing), Taiwan's AIDC (rear fuselage and tail), Australia's Hawker de Havilland (tailcone) and Fischer of Austria (fairings). AIDC is a new partner for Bombardier and, after overcoming initial issues, is performing well. "They have not held up the programme," says Holding.
Main system suppliers include Honeywell (powerplant and APU), Rockwell Collins (avionics), Messier Dowty (landing gear), ECE (electrics), Leibherr (pressurisation and flaps), Parker Abex (hydraulics), Intertechnique (fuel), Moog (flight controls), Hella (lighting), Walter Kidde (fire suppression), PPG (windows), Goodrich (wheels and brakes), Scott Aviation (oxygen), DeCrane (interiors) and NLX (simulator).
Bombardier's Belfast, Northern Ireland, plant produces the centre fuselage and its Montreal, Canada, plant the forward fuselage and flight controls. Final assembly is at the company's Learjet plant in Wichita, Kansas, which is also the location of Bombardier's flight test centre. The major sub-assemblies arrive at Wichita with systems pre-installed, and the laser-aligned mating process requires the minimum of tooling, says Holding.
Key to achieving the aggressive timescale for certification is an even more extensive use of ground test rigs at partner sites than in previous Bombardier programmes. "We have pushed partners into development of more substantial ground test rigs to minimise risk," says Holding. "We have more complete systems rigs, such as a full-scale wing anti-ice rig." In addition, Bombardier has an integrated systems development rig, or "iron bird", and complete static-test and fatigue-test airframes.
Production ready
But the biggest contributor to compressing the certification timescale is the company's drive to get the first aircraft as close to production standard as possible. When it flew for the first time on 14 August, aircraft 20001 was more complete than any previous first of type produced by Bombardier, Holding says. "All the systems were operational, including anti-ice and thrust reversers. The aircraft was in a good state of compliance."
Flight testing has been structured to minimise risk. There will be five aircraft in the 1,500h programme. Aircraft 20002, 20003 and 20004 are fully assembled and in functional testing, and are scheduled to fly this month, October and November, while 20005 is in final assembly.
The aircraft are almost identical, says Holding, which allows for flexibility in flight-test scheduling. Aircraft 20001 and 20002 are equipped with the emergency egress and spin recovery systems required for flight envelope expansion and are interchangeable.
Aircraft 20003 will be equipped with most of the optional equipment, which will be certificated at the same time as the baseline aircraft. Aircraft 20004 and 20005 will be equipped with full interiors. The interior for 20004 is already complete in the fitting jig. Aircraft 20005 will receive the interior planned for Flexjet aircraft. Early definition of the avionics options and cabin interior has reduced risk and saved time, says Chidiac. "We will fly an interior 15-18 months before delivery, and we will sell aircraft 2 through 5 at the end of the programme."
Because the first aircraft are as close to certification standard as possible, Bombardier is anticipating a minimum number of design changes during flight test. Aircraft 20005 will be held back to incorporate as many as possible of those changes that do emerge, so that "we certificate what we deliver", says Chidiac.
Hopefully, this will eliminate most of the post-certification modifications that delayed delivery of the Learjet 41 and Global Express. Tests that could potentially result in structural changes have been scheduled early in the programme. "We will do icing this winter, and we have already done the birdstrike test," says Holding. "Whatever mod line there is will be very well controlled and limited to final changes such as software."
The schedule calls for Canadian certification in the third quarter of next year, followed shortly after by US and European approval, with the first green delivery planned for the fourth quarter. Aircraft will be outfitted and painted at Bombardier's Tucson, Arizona, completion centre alongside Challengers. By defining the interior early and working with a single cabin integrator, DeCrane, the company plans to reduce the completion cycle time and improve build quality. Experience with Flexjet's high-utilisation fleet has resulted in an emphasis on the reliability and maintainability of interior components, with a 20min goal set for changing out line-replaceable units.
Ramping up production
The Continental is scheduled to enter service in the first quarter of 2003, with the first few aircraft going to Flexjet. With firm orders for 115 aircraft, Bombardier plans to ramp up production to 60 a year by the fourth year.
"The market acceptance of this aircraft is unprecedented. It is the fastest selling introduction of any aircraft," says Holding. As a result, the Continental is sold out to 2005-6. "We want to despatch the backlog quickly because is is a competitive advantage to be able to offer the aircraft quickly," says Chidiac.
Bombardier sees the strong orderbook as a vindication of its decision to design the Continental for the widest possible market acceptance, even if the result is what Chidiac admits is "rather bland" aircraft. "In 1998 we decided to design a simple aircraft for a specific mission and a dominant market share. The Continental exactly meets the requirements, and the market is responding."
Bombardier calculates the Continental took 40% of the super mid-size orders in 2000. "The backlog is large and there are no signs of orders slowing down," he adds.
Source: Flight International
