If System B quantity indicates zero and System B pressure is lost, will the power transfer unit still operate?

• A. No, PTU requires pressure to operate
• B. Yes, sufficient standpipe fluid remains
• C. Only if System A is operational
• D. Yes, but only temporarily

Answer: (B)

The power transfer unit (PTU) relies on the availability of hydraulic fluid to function. If System B shows zero quantity and has lost pressure, it indicates that there is insufficient fluid to maintain normal operations.

In this context, the option stating that "sufficient standpipe fluid remains" implies that there may still be a reserve of hydraulic fluid available in the standpipe or other sections of the system that can temporarily provide enough pressure for the PTU to operate. This scenario recognizes that although System B may not be fully functional due to the lost pressure and quantity, there could still be fluid present that allows for limited operation.

Understanding the mechanics of hydraulic systems, it's crucial to recognize that power transfer units are designed to function in emergency situations where primary systems may have failed or are under pressure loss. Therefore, the ability of the PTU to pull from residual capacity enables it to continue functioning at least for a short duration, depending on the amount of fluid that remains in the system.