What is the required action after the first and second start attempts of the APU?

When attempting to start the Auxiliary Power Unit (APU), it's crucial to follow the specified protocols for subsequent start attempts after the first and second failures. When the second start attempt does not succeed, the required action is to wait for a predefined period before trying again to avoid overheating or damage to the unit.

In this context, waiting 60 seconds after the second start attempt before attempting to start again is the correct procedure. This timeframe allows the APU to cool down sufficiently, ensuring that subsequent attempts are made under conditions conducive to successful operation. Implementing this wait time helps maintain the integrity of the APU and prevents unnecessary wear and tear on the equipment.