How are the hydraulic pumps cooled?

How are the hydraulic pumps cooled?

• A. Ram-air hydraulic fluid heat exchanger
• B. Oil cooler
• C. Liquid cooling loop
• D. Ambient air cooling only

Answer: (A)

Pumps in a hydraulic system heat the fluid as it’s moved at high pressure, so cooling comes from removing that heat from the hydraulic fluid itself. The ram-air hydraulic fluid heat exchanger does exactly that: hydraulic fluid passes through the exchanger and is cooled by the outside air (ram air) flowing over it. As the aircraft moves, this air flow carries heat away, cooling the fluid before it returns to the pump. This setup provides active cooling without needing a separate liquid coolant loop, and it’s more effective than relying on ambient air alone or a simple oil-only cooler in isolation.

Pumps in a hydraulic system heat the fluid as it’s moved at high pressure, so cooling comes from removing that heat from the hydraulic fluid itself. The ram-air hydraulic fluid heat exchanger does exactly that: hydraulic fluid passes through the exchanger and is cooled by the outside air (ram air) flowing over it. As the aircraft moves, this air flow carries heat away, cooling the fluid before it returns to the pump. This setup provides active cooling without needing a separate liquid coolant loop, and it’s more effective than relying on ambient air alone or a simple oil-only cooler in isolation.