In earlier episodes, the restoration team has been exploring, reverse engineering, and restoring a Bendix MG-1 Central Air Data Computer (Part 1, Part 2, Part 3). But once it starts to work, how do you know it’s producing correct results? A pitot/static test set generates precisely calibrated pressure values to simulate sensors on an aircraft in flight, allowing test of flight instrumentation over the full flight envelope. Modern units are complicated and very expensive, so the team turns to a test set produced by Smiths Aerospace in Britain for the Royal Air Force, manufactured around 1960, and using some of the earliest transistor electronics. The device was built with military-grate ruggedness, but its electro-mechanical-pneumatic insides are showing their age. Can it be brought back to life?