What is the primary function of the second detent on the parking brake handle regarding engine operation?

The second detent on the parking brake handle serves a crucial function in ensuring that the engine continues to operate under specific circumstances. When the parking brake is engaged, the second detent provides a level of safety and operational capability by allowing certain engine parameters to remain active. This can be particularly important during ground operations where it is necessary to maintain engine performance for tasks such as taxiing or to provide hydraulic power.

Understanding the role of this detent supports the safety protocols within the aircraft's operational framework. It prevents accidental shut down of the engines when the parking brake is engaged, thus ensuring the pilot can manage the aircraft effectively during various phases of ground operations. This aspect of the design emphasizes the importance of maintaining control and function while the aircraft is stationary or during slow movements.