What are the APU accumulator pressure limits?

The correct answer is based on the operational specifications for the Auxiliary Power Unit (APU) accumulator pressure limits, which are crucial for ensuring safe and efficient APU operation. The APU accumulator provides hydraulic pressure to the aircraft's systems, and maintaining it within the specified limits is vital for functionality.

The pressure range of 2700 to 3100 psi is established as the optimal operational limit, ensuring that the hydraulic systems can perform effectively without risking damage to components or system failures. This pressure range supports the necessary functions, such as starting the APU and enabling its operations in various environmental conditions.

In contrast, the other options fall outside of these parameters. Options with lower maximum pressures or higher minimum pressures do not align with the required specifications for safe APU operation, making them unsuitable choices. Understanding these limits is crucial for plane captains to ensure that all systems are functioning properly and safely during operations.