Carbon Tracking

An ignition system malfunction caused by a fine track of carbon deposited inside the distributor of an aircraft magneto. The resistance of the air inside the distributor at high altitude is so low that it is possible for a spark to jump between the distributor terminals. As this spark moves across the surface of the distributor block, it leaves a thin track of carbon. The resistance of this carbon track is so much lower than that of the material of which the distributor block is made that high voltage leaks through it during normal engine operation. This high-voltage leakage can cause misfiring, loss of engine power, and possible engine damage.