Series 705 first to receive enhancements providing better performance and range

Enhancements announced for Bombardier's CRJ900 regional jet will make their debut later this year with delivery of the first CRJ700 Series 705LR to Air Canada. The 75-seat Series 705 uses the airframe of the CRJ900, and changes introduced to improve airfield performance and increase range will be certificated first for the 705, then for the CRJ900.

The enhanced CRJ900 airframe is one of a series of improvements to the 70- to 86-seat CRJ700/900 family introduced by Bombardier in response to customer request or anticipation of market demand.

The CRJ700 will be offered with the General Electric CF34-8C5 powering the stretched CRJ900, derated to the 12,700lb (56.4kN) normal take-off thrust of the existing -8C1. This will offer engine maintenance cost savings of up to 15% over 15 years, Bombardier says, and provide commonality with the CRJ900 powerplant. The derated CF34-8C5B1 will be available in the second quarter and is planned to become the standard engine on new production CRJ700s, says Rod Williams, vice-president, programmes and planning, Bombardier Regional Aircraft.

While existing CRJ700 operators will still be able to specify the -8C1 engine, he says, GE is introducing the option to upgrade the -8C1 to -8C5 standard during overhaul.

Bombardier is also introducing a third, Long Range (LR), variant of the CRJ700 with higher weights. Compared with the CRJ900ER, the LR option increases maximum take-off weight (MTOW) by 907kg to 34,900kg, maximum landing weight (MLW) 272kg to 30,600kg and maximum zero-fuel weight (MZFW) 1,020kg to 35,200kg. Range is increased by 442km (239nm) to 4,040km. The LR option will be available on new production aircraft and for retrofit to in-service CRJ700s in the first quarter of 2006. William says certification will involve re-analysis of existing work, and is expected to be a paperwork change and require minor physical changes, if any.

The landing gear may be changed in production for commonality with the strengthened undercarriage on the LR variant of the CRJ900, which Bombardier is also introducing. Compared with the CRJ900ER, the LR option increases MTOW by 907kg to 38,400kg, MLW by 680kg to 34,000kg and MZFW by 272kg to 32,000kg. Range is increased by 252km to 3,660km. Williams says impetus for introducing increased gross-weight versions of the CRJ700 and 900 was provided by the US Federal Aviation Administration's decision to increase the standard passenger weight from 91kg to 100kg.

CRJ900 enhancements include new, longer-span winglets that cant outwards 40°, instead of 20°, providing an net wing span and area increase and increasing lift-to-drag ratio. This reduces overall fuel consumption by 1%, Williams says. Wing leading-edge slats are rescheduled to deploy 20°, rather than 25°, when trailing-edge flaps are at 20°, improving take-off performance. Landing reference speed is lowered, reducing landing distance.

The enhanced CRJ900 will be available in the second quarter, and will be the standard airframe for new customers. The LR option will also be available in the second quarter, but will only be available for CRJ900s either built or upgraded to the enhanced airframe standard.


Source: Flight International