Which component located in the utility module isolates a leak in the APU Accumulator?

Which component located in the utility module isolates a leak in the APU Accumulator?

• A. The APU Shutoff Valve
• B. The Transfer Valve
• C. The Velocity Fuse
• D. The Hydraulic Pressure Regulator

Answer: (C)

The key idea is how the system protects itself from a leak in the APU accumulator. The velocity fuse is a self-contained device in the utility module that responds to a rapid change in fluid flow. If the APU accumulator starts leaking, the flow velocity through the line spikes, triggering the fuse to close off that path and isolate the leak. This prevents hydraulic fluid from continuing to escape into the rest of the system and maintains overall hydraulic integrity. The other components don’t perform this local isolation role. The APU shutoff valve is meant to stop all APU-derived hydraulic power by shutting off the APU supply, not to isolate a leak within the accumulator itself. The transfer valve directs fluid between sources but doesn’t act as a leak-isolating device. The hydraulic pressure regulator controls system pressure rather than isolating a leak.

The key idea is how the system protects itself from a leak in the APU accumulator. The velocity fuse is a self-contained device in the utility module that responds to a rapid change in fluid flow. If the APU accumulator starts leaking, the flow velocity through the line spikes, triggering the fuse to close off that path and isolate the leak. This prevents hydraulic fluid from continuing to escape into the rest of the system and maintains overall hydraulic integrity.

The other components don’t perform this local isolation role. The APU shutoff valve is meant to stop all APU-derived hydraulic power by shutting off the APU supply, not to isolate a leak within the accumulator itself. The transfer valve directs fluid between sources but doesn’t act as a leak-isolating device. The hydraulic pressure regulator controls system pressure rather than isolating a leak.