Bombardier says it will have its final assembly line for the Learjet 85 in Wichita, Kansas, up and running by mid-July at the latest - approximately one year ahead of the expected US Federal Aviation Administration (FAA) certification of its largest Learjet family member.
The final assembly line will be pressed into service initially to build the five flight test aircraft for the programme. Workers in Wichita will assemble the composite fuselage sections and join with composite wings, Pratt & Whitney Canada PW307B turbofans and other subsystems. "The tooling is there; the people are trained," says Ralph Acs, Bombardier Learjet vice president and general manager.
Acs says all major composite sections for the first aircraft have been fabricated in the company's facility at Queretaro, Mexico, and in some cases, components have been made for the two additional aircraft. While all eight composite fuselage sections - built using a hand layup and vacuum-bagged curing process - are made in Queretaro, Bombardier builds the eight-passenger business jet's composite planks and wing spars in its Belfast, Ireland, facility and ships the components to Queretaro for assembly into wings. Spars are built using the resin transfer infusion (RTI) process that Bombardier developed for its CSeries single-aisle commercial airlines programme. The first spars and planks have been delivered to Queretaro.
In the early stages of the programme, Acs says Bombardier will receive components for the empennage and horizontal stabiliser from Queretaro and assemble the sections in Wichita. "The idea was [to assemble] the empennage and horizontal stabiliser for the early ship sets [in Wichita] to spread the overall load," he says. When complete, the pulsed final assembly line will hold five aircraft at any one time.
The reduced pressure effects of altitude on vacuum bagging during the cure process at Queretaro, which sits approximately 6,000ft (1,829m) above sea level, are being mitigated by a "debulking" process, says Acs: "It's all about extracting the air. Every five or so plies, you debulk for five hours."
The process involves squeezing out the air and volatiles between plies. "The debulking process is emphasised due to the altitude [of the facility]," says Acs. "At sea level, you don't have to do it as often."
Source: Flight International
