APS3200 APU is a very smart engine. Each cycle it generates an advanced performance report with data. Prognos for APU, our state of the art fleet management platform uses this data to predict when the APU is about to fail. With this software our engineers are able to remove the APU before failure.
Data alone is not sufficient, our APU engineers are constantly monitoring the engine performance of about 1000 aircraft. How we do? Check out this video.