As an avionics engineer, could I butt in to explain a bit about the evolution of compasses and compass swinging?
Purely magnetic compasses evolved to gyro stabilised compasses using a "flux detector" that served as the actual compass. On smaller aircraft these were (and in many aircraft, still are) swung in the traditional manner. In larger aircraft such as the B707, VC10 and early B747s for example, an "electrical" swing was used. An electro-magnetic table would be placed below the flux gate and instead of the earth's magnetic field being held steady while the aircraft was moved, the aircraft would remain stationary while a simulated earth's field was rotated beneath it. With the advent of inertial reference systems employing laser gyros the compass system has disappeared. IRS is far more exact than magnetic detection and the compass swing has disappeared. The standby compass is "swung" against the inertial system, usually during revenue flight, and it is in any case only accurate within 5 degrees. Lugging an A380 round a compass base would be an interesting procedure to say the least
