In what situation would the standby hydraulic system likely be activated?

• A. During routine maintenance checks
• B. When the primary hydraulic system fails
• C. During engine start-up
• D. For fueling operations

Answer: (B)

The standby hydraulic system is specifically designed to activate when the primary hydraulic system fails. This is a critical safety measure ensuring that essential systems, such as flight controls or landing gear, can still operate in the event of a primary failure. The standby system serves as a backup, allowing for continued functionality and mitigating the risk of total hydraulic failure during operations.

In contrast, the other choices relate to scenarios where the primary system is functioning properly. Routine maintenance checks typically do not require activation of the standby system, as these checks are conducted while ensuring all systems are operational. Engine start-up processes generally rely on the primary system and do not necessitate the use of a standby. Fueling operations are also separate from hydraulic functions and would not trigger the standby system's activation.