Engineering Solutions to Everyday Industrial Problems
Hydraulic and fuel lines on Cessna Aircraft Co.'s Citation X business jet comprise about 700 assemblies of small diameter tubing. In the past, the lines were flared and fastened with fittings, but to reduce the weight of the plane, Cessna wanted to use titanium, which had to be assembled by welding. About 60% required a weld on both ends and the rest needed a weld on one end. Conventional gas tungsten arc welding (GTAW) can be used on larger diameter titanium lines but generally can't produce an acceptable weld quality on the smaller diameters, especially below 0.75 in. (19 mm). Changing to titanium lines presented a challenge of fastening small-diameter titanium lines while meeting extremely high levels of quality and reliability.