The quadrant sketched here is part of the control system for the wing-elevator of a commercial aircraft. It is to be made of a light alloy (aluminium or magnesium) with the shape shown in the figure. It weighs about \(5 \mathrm{~kg}\). The minimum section thickness is \(5 \mathrm{~mm}\), and - apart from the bearing surfaces - the requirements on surface finish and precision are not strict: surface finish \(\leq 10 \mu \mathrm{m}\) and precision \(\leq 0.5 \mathrm{~mm}\). The bearing surfaces require a surface finish \(\leq 1 \mu \mathrm{m}\) and a precision \(\leq 0.05 \mathrm{~mm}\). A production run of 100 is planned.