Which procedure ensures energy isolation of hydraulic systems during landing gear maintenance?

• A. De-energize hydraulics
• B. Lockout/tagout procedures
• C. Wheel chocks
• D. Wear PPE

Answer: (B)

Isolating hydraulic energy before any maintenance is essential to prevent unexpected movement or fluid release while technicians work on the landing gear. The proper method is lockout/tagout procedures. This approach identifies every energy source feeding the hydraulic system, then physically locks the controls or energy valves in the off position and applies standardized tags to warn that maintenance is in progress. The lock physically prevents anyone from re-energizing the system until the lock is removed by the person who applied it, and verification steps confirm the system is de-energized.

In landing gear work, this protects you from accidental actuations, which could extend or retract gear or release hydraulic fluid under pressure, risking injury and damage. The procedure also typically includes releasing stored pressure and ensuring zero energy before starting work.

De-energizing hydraulics alone may stop the main power source but doesn’t prevent re-energization or account for stored energy. Wheel chocks stop the aircraft from moving but don’t isolate hydraulic energy, and wearing PPE, while important for safety, does not address energy isolation itself.