High hydraulic pressure is indicated by which of the following?

High hydraulic pressure is indicated primarily by the pressure gauge, which provides real-time measurements of the hydraulic system's pressure levels. A properly functioning pressure gauge will display the pressure and allow the crew to monitor whether it falls within the normal operating range or indicates an abnormal situation, such as high pressure.

While warning alarms and visual indicators on the dashboard can play a role in alerting the crew to abnormal conditions, they typically serve as secondary systems that rely on the readings from the pressure gauge. Manual checks by the crew are important for verifying gauges and other indicators but do not provide an immediate and reliable measurement of hydraulic pressure during flight operations. Thus, the pressure gauge is the most direct and effective means of monitoring hydraulic pressure.