Final answer:
In an APU assisted engine ground start, the ITT must not exceed a certain limit before moving the thrust lever to IDLE.
Step-by-step explanation:
Before moving the thrust lever from SHUT OFF to IDLE, the ITT must not exceed the maximum limit specified by the manufacturer. This limit is usually expressed in degrees Celsius or Fahrenheit.
For example, let's say the maximum ITT limit for a particular engine is 750°C. During the start sequence, the ITT rises as the engine spins up. The pilot or ground crew must closely monitor the ITT and ensure it remains below the specified limit before advancing the thrust lever to the IDLE position.