What condition could lead to the activation of the PTU for pressure management?

The condition that could lead to the activation of the PTU (Power Transfer Unit) is a difference in pressure between the hydraulic systems. The PTU is designed to automatically engage when a significant pressure disparity occurs between the green and yellow hydraulic systems. This typically happens when one system experiences a drop in pressure due to high demand or a failure, while the other system maintains normal pressure levels. By activating the PTU, hydraulic fluid from the higher-pressure system is used to assist the lower-pressure system, thereby helping to maintain adequate hydraulic pressure for critical aircraft operations. This functionality is essential for ensuring the safe operation of flight controls, landing gear, and other hydraulic systems in the aircraft.

The other conditions listed do not directly trigger the PTU. High oil temperatures primarily affect engine performance rather than hydraulic pressure balance. Low fuel levels in the wings concern fuel management rather than hydraulic systems. Non-operational engines may result in other operational deficiencies, but they do not directly influence the hydraulic system's pressure difference that would activate the PTU.