When the hydraulic system is fully pressurized, the PRESS PSI indicator reads which range?

• A. 3200-3600
• B. 3800-4200
• C. 4000-4600
• D. 3600-3800

Answer: (B)

The main thing this question tests is understanding what the PRESS PSI indicator shows when the hydraulic system is at full capacity. The indicator reflects the actual pressure in the hydraulic circuit, and when the system is fully pressurized, the pumps have built up pressure to supply all actuators with enough force.

For this aircraft, full pressurization corresponds to about 3,800 to 4,200 psi. This range represents the design operating pressure and accommodates typical variations due to temperature, pump speed, and minor line losses. Seeing a reading in this band indicates the hydraulic system is ready to deliver the needed power to braking, steering, and other hydraulic components.

If the pressure were significantly lower, it would suggest the system isn’t fully charged—possible causes include a pump issue, a leak, or air trapped in the lines. If it were outside the upper end, it could signal an overpressure condition or a relief/monitoring action kicking in.