Final answer:
In aviation, the air turbine starter system is used to start jet engines and should not be engaged while the engine is already rotating, as it could cause damage, so the statement is true.
Step-by-step explanation:
The student's question, "The air turbine starter cannot be engaged when the engine is rotating." appears to be related to the operation of an air turbine starter system, typically used in aviation to start jet engines. Since the air turbine starter is designed to rotate the engine to a speed where it can sustain combustion on its own, it should not be engaged while the engine is already rotating. This could cause damage to the starter system or the engine. Therefore, the statement is True: the air turbine starter cannot be engaged when the engine is rotating because it is designed to initiate rotation, not to interact with a rotating engine.