Graham Warwick/WASHINGTON DC
Bombardier has begun a performance enhancement programme (PEP) for its Global Express business jets. The aircraft are emerging from completion centres with heavier interiors than were allowed for during design, resulting in a range reduction. A package of aerodynamic and other improvements is intended to restore their original performance.
The Global Express' maximum design range of 12,000km (6,500nm) was based on an interior completion allowance of 2,725kg (6,000lb). Of the 14 aircraft that have entered service so far, the lightest interior is 2,747kg and the heaviest is 3,558kg, says Global Express director Luc Fouquette.
The average interior weight is 3,137kg, and this has been adopted as the baseline completion allowance. The result is a 166km (90nm) reduction in maximum range. "This is still 100nm [185km] more than any other aircraft in its class," says Fouquette.
The PEP is expected to add 185km to the aircraft's range. The package of "minor changes" includes sealing or reducing gaps around the thrust reverser doors, between the horizontal and vertical stabilisers and at the ailerons.
"The tolerances allowed during design were too much," says Fouquette. Other drag-reducing changes include a redesigned forward wing-body fairing, improved seal between the fuselage and wing, and the addition of louvres to the environmental control system exhaust.
The biggest changes are a redesign of the engine exhaust mixer to reduce drag and modification of the fuel-scavenging system to recover 63.5kg more fuel.
PEP changes are being introduced in stages. They will be incorporated in new production aircraft by the first quarter next year. The improvements are free to customers for retrofit into aircraft in service or in completion.
Source: Flight International
