By many accounts, Bombardier's Learjet 60XR manufacturing operation in Wichita represents the "last bastion" of the classic metal aircraft and the classic metal aircraft production process.

"It's a derivative of the very first Learjet," says Larry Thimmesch, project manager for the Learjet programme for Bombardier in Wichita, of the structural design philosophy for Learjet 60XR, the latest evolution of the company's mid-size, stand-up cabin jet. The line began with the Learjet 55, launched in 1977. The all-metal aircraft features an eight-spar wing that originated with the single-seat Swiss fighter, the FFA P-16, on which Bill Lear modelled the first Learjet 23 in the early 1960s. "It's a bullet-proof aircraft, literally," says Thimmesch. "You could shoot out every other spar and the aircraft could keep flying."

Though there are inefficiencies in over-designing an airframe, ie weight and extra materials, Bombardier's cost-benefit analysis for an update to the Learjet 60 in the 2003 timeframe favoured keeping the legacy design in place rather than bringing in composite technologies. For the recently launched eight-passenger Learjet 85, Bombardier outsourced the main structure of the aircraft to German aerospace composites expert, Grob.

The cost-benefit analysis also dictated keeping the entire build process at the company's "centre of excellence" in Wichita, making the Learjet 60XR the only Bombardier business aircraft built start-to-finish in one location by one workforce. As such, the aircraft's hand-built wing and fuselage are built as two separate assemblies at the plant in Wichita then joined in the final assembly and completions area, again at the same plant.

Other Bombardier business aircraft, from the Learjet 40XR to the Challenger 605, are built in sections at a variety of Bombardier plants then shipped to a final assembly location for construction. In Wichita, wings for the Learjet 40XR and Learjet 45XR arrive from Bombardier's DeHavilland facility in Toronto and are mated with fuselages coming from its Shorts facility in Northern Ireland.

One key benefit of having everyone in-house is response time, says Thimmesch. "It's the shortest supply line and it's very responsive to change," he says. "There's an immediate benefit in that the final assembly group is the end customer for the nearby wing and fuselage group. If an issue comes up, they can send someone over immediately to fix it."

Source: Flight International