What safety measure prevents APU overspeed?

What safety measure prevents APU overspeed?

• A. Emergency fuel shutoff valve
• B. Overspeed governor that shuts down the unit
• C. Throttle limiter
• D. Automatic restart feature

Answer: (B)

The overspeed governor is a crucial safety feature in the APU designed to regulate the operational speed of the unit. Its primary function is to prevent the APU from exceeding a predetermined speed, which could lead to mechanical failure or catastrophic damage. When a certain speed threshold is reached, the overspeed governor intervenes by shutting down the unit, thereby protecting both the APU itself and the aircraft from potential hazards associated with overspeed conditions. This system is vital for maintaining optimal performance and ensuring safety during APU operation. The other measures, while they may contribute to overall safety and operation, do not specifically address overspeed situations in the same direct manner as the overspeed governor.

The overspeed governor is a crucial safety feature in the APU designed to regulate the operational speed of the unit. Its primary function is to prevent the APU from exceeding a predetermined speed, which could lead to mechanical failure or catastrophic damage. When a certain speed threshold is reached, the overspeed governor intervenes by shutting down the unit, thereby protecting both the APU itself and the aircraft from potential hazards associated with overspeed conditions.

This system is vital for maintaining optimal performance and ensuring safety during APU operation. The other measures, while they may contribute to overall safety and operation, do not specifically address overspeed situations in the same direct manner as the overspeed governor.