How is a leak in the 1st stage primary servos isolated?

• A. Turn off the master battery switch
• B. The pilot by moving the SERVO OFF switch to the 1st stage
• C. Pull the circuit breaker for the tail rotor system
• D. Close the bleed valve

Answer: (B)

The test is about quickly isolating a hydraulic leak by targeting the affected stage. In the UH-60, the SERVO OFF switch is used to shut off hydraulic flow to a specific servo stage. Setting it to the 1st stage removes hydraulic pressure from the first-stage primary servos, effectively isolating that stage from the rest of the system. This contains the leak, reduces fluid loss, and prevents contamination from spreading, while preserving the other hydraulic circuits for continued control.

Other actions aren’t appropriate for this situation: turning off the master battery cuts power to the entire helicopter, pulling a tail rotor circuit breaker doesn’t isolate the first-stage servos, and closing a bleed valve isn’t a reliable way to stop a leak or isolate the affected circuit.