When N2 increases to greater than ____ percent, the FADEC no longer monitors start parameters.

The correct answer is based on the operational characteristics of the Full Authority Digital Engine Control (FADEC) system used in the A320. Specifically, when the N2 (the engine's high-pressure rotor speed) exceeds 50 percent, the FADEC determines that the engine is successfully started and transitions from monitoring start parameters to normal operational parameters.

This threshold is significant because during the engine start process, the FADEC closely monitors certain parameters, such as N2, to ensure that the engine is starting correctly. If any anomalies or issues occur during the start, the FADEC can make decisions to abort the start to prevent potential damage or failure. Once N2 reaches above the 50 percent mark, the assumption is that the engine's start sequence is complete, and normal operational oversight can take over without the necessity for intense monitoring of start parameters.

Reaching N2 above this rate indicates that the engine has stabilized in its operation, moving beyond the critical start phase where precise control and monitoring are essential. This is why it’s key to understand the context of FADEC functions and engine operating parameters during different phases of engine operation.