Story ID: 030
Canadair Challenger: A Widebody Pioneer
By: David Donald
Caption: Bombardier's successful programs trace back to a company that produced flying boats during World War II
Word Count: 1954
Bombardier’s Challenger jets remain strong sellers today but the roots of these programs, as well as of its flagship Globals, trace back decades to the company Canadian Vickers, which produced large numbers of PBV-1 Canso (license-built Catalina) amphibious aircraft for the Allied war effort in World War II.
In 1944, it was taken over by the Canadian government, although it was sold in 1946 to what later became General Dynamics. A vast production facility was constructed at Cartierville in Quebec, which during the Cold War built CL-13/F-86 Sabres, CL-90/F-104 Starfighters, and CL-219/F-5 Freedom Fighters to assist with the rearming of NATO air arms. There were commercial projects, too, such as the CL-44 derivative of the Britannia airliner, the CL-66 version of the Convair CV-540, and the CL-215 amphibian.
By the mid-1970s, much of that business was gone. Major contracts had been fulfilled but not replaced, and the workforce had been slashed from 10,000 to 1,400. A new major project was desperately needed.
Enter Bill Lear. The legendary creator of the Learjet had left his company in 1969, having sold it to Gates two years previously. In the early 1970s, he had reasoned that the business jet market would come under increasing pressure as oil prices rose, culminating in the 1973 oil crisis. The future of the thirsty, turbojet-powered aircraft that dominated the market looked bleak.
Lear also recognized that there had been several critical developments in technology that had not yet arrived in the bizjet arena, principally the use of fuel-efficient turbofans and the aerodynamically efficient supercritical wing. He schemed a concept that included both, which he named the Learstar 600.
Armed with his design and backed up by data that underlined its efficiency, Lear visited all of the U.S. manufacturers to tout the Learstar 600, but all had invested heavily in their existing designs and had no appetite for a new aircraft program. So, with one eye on the near-empty Cartierville factory and an under-employed design staff of experienced engineers who were no strangers to innovation, Lear called Canadair.
Initially, at least, the pitch had a lukewarm reception, but there was sufficient interest for a study to be launched that pitted the Learstar against likely rivals, such as the Falcon 50 and Gulfstream II. The results were favorable enough for further work to proceed from late 1975.
In the following year, the government re-acquired Canadair and began secretly funding the program. This had come about in part due to personal conversations between Lear and future prime minister Jean Chrétien, who was minister of trade and industry, and later finance, during this time. The secret nature of the support later caused controversy in Canada.
Canadair officially acquired the Learstar 600 program in April 1976 and began detailed design work. The project was formally launched on Oct. 29, 1976, at which point Canadair had taken 53 firm orders. The launch customer was Federal Express, which placed an order for 25 parcel carriers.
At its instigation, the design incorporated a large cargo door from the outset. However, FedEx canceled its order following the overturning of aircraft size restrictions in the freight market, resulting in the company turning to the Boeing 727 instead.
Lear’s original concept had been little more than that, and the eventual aircraft was in most respects a clean-sheet Canadair design. There were many changes made: the low-set tailplane was replaced with a T-tail to raise the surfaces out of the jet efflux; the original Garrett TFE731 turbofans were replaced by Avco Lycoming ALF 502s, largely at the behest of FedEx; fuel carriage was moved to the supercritical wings; and, most importantly, the fuselage was enlarged to provide “widebody” accommodation for either freight or passengers.
In March 1977, the aircraft was renamed the CL-600 Challenger. Lear had disliked the widebody approach, disparagingly referring to the aircraft as “Fat Albert,” and such disagreements led to his ousting from the program. He died in May 1978.
Into the Air
By early 1977, three prototypes were under construction. A mock-up was displayed at the Paris Air Show that year, and by the year's end, orders had topped 100. The appearance of the Challenger spurred the development and launch of the rival Citation III and Gulfstream III.
Canadair rolled out the prototype (C-GCGR-X, c/n 1001) on May 25, 1978, powered by the 7,500-pound thrust ALF 502L. The first aircraft took to the air at Montreal on Nov. 8, 1978, piloted by Norm Ronaason and Doug Adkins, with the second and third joining it on test duties in the following year.
After around 25 flights from Montreal, the flight test and certification campaign was moved to Mojave in California to take advantage of better weather. The first aircraft was lost in a crash there on April 3, 1980. One Canadian Department of Transport regulator demanded that the new aircraft have an aerodynamic deep-stall protection capability, despite U.S. and European officials having accepted electrical stick-shakers and -pushers.
Accordingly, Canadair was forced to add a small surface that made one wing stall before the other, so causing a routine fall-off stall before the deep stall that plagued T-tail designs could develop. This requirement was later dropped from the certification approval, but not before it led to tragedy.
A series of trials were conducted to optimize and validate the strake design, with the prototype fitted with an anti-stall/spin chute. During one flight, an anomalous noise—later traced to an engine issue—was detected, and additional flights were planned to investigate. In one of these flights—1001’s 354th—the aircraft entered a deep stall and the chute had to be deployed. The stall was overcome as advertised, but the explosive release bolts that were designed to jettison the chute failed. The aircraft plummeted down to 6,000 feet, at which point the pilot, Norm Ronaason, ordered the crew to bail out. All three escaped the aircraft, with co-pilot Dave Gollings and test engineer Bill Scott surviving. Ronaason, however, had insufficient altitude for his chute to deploy properly and was killed.
Despite the crash, the CL-600 received Canadian certification in August 1980 and FAA approval in November, albeit with mtow restrictions. There were numerous issues to overcome, including icing and being overweight, while the ALF 502L engines struggled to meet specifications and were prone to compressor stalls. Nevertheless, Canadair built 81 CL-600s.
TAG Aviation was the first recipient. In addition to private and corporate buyers, 12 were bought by the Royal Canadian Air Force for use as CC-144 passenger/light transport aircraft (eight) and CE-144 electronic warfare trainers (three). The 12th was the second prototype, which was employed on trials duties as the CX-144.
Challenger Developments
Development of the CL-600 family began before the type had flown, the initial derivative being the CL-610 Challenger E. This was a stretched version that was offered to FedEx in place of the 25 CL-600s on order following the deregulation of freight aircraft. As noted previously, FedEx canceled its order and a stretched version of the Challenger was shelved while Canadair focused on the executive model.
The original Challenger’s Achilles heel was its powerplant and, even while initial deliveries were just getting underway, Canadair announced the CL-601. This would have winglets for increased aerodynamic efficiency and a switch in the engine to the more powerful 8,650-pound General Electric CF34-1A turbofan, which could be distinguished from the ALF 502 by having a reduced-length cowling and exposed nozzle section. Three late-production CL-600s were completed with the winglets as the CL-600S.
The third prototype was adapted to the CL-601 configuration and made its first flight as such on April 10, 1982. The new CL-601-1A model proved popular in the marketplace and was further developed into the CL-601-3A with 9,220-pound CF34-3A engines and a glass cockpit. Both -1A and -3A were offered in an ER extended-range version with an additional fuel tank in the fin. The tank was standard in the final CL-601-3R sub-variant.
Next came the CL-604, for which the third prototype again provided the initial test platform. This model introduced saddle tanks to increase fuel capacity, structural improvements, and a new undercarriage that permitted higher takeoff weights. Rockwell Collins Pro Line 4 avionics were installed. A number were supplied to military users, including maritime surveillance aircraft for Denmark.
After more than 350 CL-604s had been built, the CL-605 was introduced in 2005. It had Pro Line 21 avionics and larger cabin windows. A new tailcone design was introduced. A further refresh to the design came in 2015 with the Challenger 650. A new cabin interior, Pro Line 21 Advanced avionics with synthetic vision system, and an increase in takeoff thrust were the principal new features. The 650 remains in production, with around 1,100 CL-600 family aircraft having been built to date.
Stretching the Challenger
Early delivery delays and issues with the CL-600 had nearly caused Canadair’s bankruptcy, and despite the boost in sales created by the CL-601, the government sold off the company to Bombardier in 1986. One of the new owner’s first projects was to begin development of a stretched version that was considerably more ambitious than the earlier CL-610. The result was the Canadair Regional Jet, or CRJ, formally launched in 1989.
Bombardier capitalized on the ability of the Challenger’s cabin to accommodate a 2+2 seating arrangement. By adding a 128-inch plug ahead of the wing and a 112-inch plug aft, the length was increased to 87 feet 10 inches, sufficient for 50 seats to be installed. On May 10, 1991, the first CRJ-100 took to the air, powered by 8,730-pound CF34-3A1 engines.
Sales were brisk, and the CRJ-200 followed soon after with more efficient CF34-3B1 engines. More than 1,000 CRJ-100/200s were built but operators were clamoring for more seats. Bombardier responded with the CRJ-700, with a further stretch to 106 feet 1 inch length and typical accommodation for 70 passengers. Subsequent stretches introduced the CRJ-900 (118 feet 11 inch/90 pax) and CRJ-1000 (128 feet 5 inch/104 pax). Sales of the longer CRJs added another 896 aircraft to the production list. CF34 power was retained throughout, and all of the aircraft were designated as subvariants of the CL-600 on the type certificate.
Bombardier also produced a business jet variant, dubbed Challenger 800, which was based on the CRJ-200. It was followed by the updated Challenger SE (later Challenger 850), which had the option of additional fuel tanks. Production of the CRJ-based bizjets reached 74 by the time production ended in 2012.
CL-600’s Legacy
Although embodying many features and technologies from the Challenger 600 family, the Challenger 300 (originally known as the Continental) was a clean-sheet design first flying in August 2001 and is still in production in its updated Challenger 3500 form.
In the meantime, Bombardier had been working on a vastly more ambitious new aircraft, the BD-700 Global Express. While it was essentially a clean-sheet design, the long-range aircraft naturally drew on experience from the Challenger and CRJ families, and all members of the Global family share the same fuselage cross-section initially introduced by the CL-600. The Global family has subsequently grown to become a major success for Bombardier.
One particular Challenger also played a significant role in the development of the later Global variants. The long-serving third CL-600 prototype was modified into the Active Control Technology testbed for fly-by-wire flight control systems. Flying as such from 1999 to 2004, the ACT aircraft contributed to the development of the Global 7500. It is now on display at the Canada Aviation and Space Museum at Rockcliffe in Ottawa. The second prototype also survives, displayed in the Air Force Heritage Park in Winnipeg, Manitoba.