What are aircraft hydraulic-system hazards?

• A. Hydraulic systems operate around 3,000 psi and may contain up to 185 gal; high pressure can sever fingers, hands, or limbs.
• B. Hydraulic systems operate at low pressure and pose no physical risk.
• C. They only contain hydraulic fluid in emergency lines.
• D. They operate at approximately 500 psi and rarely contain more than 20 gallons.

Answer: (A)

Aircraft hydraulic systems store and move energy through fluids at very high pressure. This energy means a line or component can release a powerful jet or a sudden surge if it ruptures, is damaged, or is accidentally actuated while being worked on. The pressure is typically thousands of pounds per square inch, and on large aircraft the hydraulic system can hold hundreds of gallons of fluid. That combination of high pressure and substantial fluid volume makes hydraulic lines capable of causing severe injuries, including deep lacerations or even injection injuries where fluid is forced into skin or tissue. The hazard isn’t limited to moving parts; a released jet or spray can propel objects, damage nearby surfaces, or contaminate skin and eyes with fluid that can be caustic to tissue. In rescue or maintenance situations, it’s essential to treat hydraulic lines as high-energy potential sources: avoid contact, depressurize and isolate circuits before work, and use appropriate PPE and procedures to prevent exposure.