CRJ700/900 to fly farther, for less

 - January 31, 2007, 7:44 AM

Bombardier has answered the call for a series of improvements to its line of 70- to 86-seat RJs, ranging from new engines on the CRJ700 to wing modifications on the CRJ900. Bombardier also plans to certify its CRJ700 and CRJ900 for higher mtows, giving each significantly more range.

According to Bombardier marketing v-p Barry McKinnon, the company began working on the various programs roughly a year ago at the behest of prospective customers. The CRJ700 program has centered on fitting derated versions of the engines used in the CRJ900 into the smaller jet. Slated for installation in production CRJ700s starting by the end of the second quarter, the new CF34-8C5B1 will replace the CF34-8C1.

Because the CRJ700 engine will run at lower thrusts than the CRJ900’s CF34-8C5, operators will see more time in service between overhauls, longer parts life and, hence, lower direct maintenance costs, said McKinnon. Bombardier estimates that a typical operator will see direct maintenance cost savings of 15 percent over 15 years.

Since the effort will result in a common engine for the CRJ700 and CRJ900, it will simplify fleet management and cut spares investment. The upgrade will also allow GE to end production of the CF34-8C1 and concentrate its development efforts and resources on a single engine type. General Electric plans to offer the upgrade to operators of existing engines as they come due for their first major shop visit.
In a completely separate effort, Bombardier introduced a new, longer- range variant of the CRJ700 scheduled for certification during next year’s first quarter. The new CRJ700LR will fly as far as 2,186 nm–some 240 nm farther than Bombardier’s
extended-range CRJ700ER. Bombardier achieved the gain by increasing the airplane’s mtow by 2,000 pounds, to 77,000 pounds, allowing operators to carry more fuel and better manage the higher passenger-weight assumptions the FAA recently mandated. The so-called paperwork mod also increased the CRJ700’s maximum landing weight by 600 pounds, to 67,600 pounds, and its zero fuel weight by 1,195 pounds, to 63,495 pounds.

Of all the improvements Bombardier introduced last month, the only real airframe changes involve the CRJ900, most notably a wingtip extension and a shallower winglet angle. Program engineer Eric Vandenberg explained that the larger wing area decreases wing loading and, therefore, results in better climb rates. Engineers also changed the flap settings at which the CRJ900’s slats deploy, allowing for lower approach speeds. The changes will also reduce fuel burn, said Vandenberg. At press time Bombardier had finished most of the flight testing on the LR prototype at its facilities in Wichita, and had begun detailed data analysis and certification documentation.

Meanwhile, Bombardier has found enough margin in the CRJ900’s weight limits to launch a new long-range variant of that airplane as well. As with the CRJ700LR, the CRJ900LR allows for both increased range and payload. As a result, it can carry a full 86-passenger load more than 895 nm from a 5,800-foot runway. All told, the changes extend the maximum range of the CRJ900LR to 1,976 nm.

McKinnon said the CRJ900’s only operator, Mesa Air Group, did not ask for the performance and range improvements. However, the benefits will also extend to the 75-seat CRJ705, which uses the same airframe and engines as the CRJ900. Air Canada stands as the launch customer for that airplane and expects to start taking delivery of its firm order for 15 of the improved versions this summer.