Following TRU fail, which components are active?

Following TRU fail, which components are active?

• A. Essential DC bus components powered by battery
• B. Avionics powered by external power
• C. Hydraulic pumps energized
• D. All systems fail to power

Answer: (A)

When the Transformer Rectifier Unit fails, the normal path that converts generator output to DC for the essential bus is lost. The aircraft’s battery then supplies the essential DC bus, keeping critical equipment alive for a limited time. So components on the essential DC bus that are designed to run from the battery remain active. Avionics powered by external power won’t be guaranteed unless external power is connected, hydraulic pumps are typically not driven directly by the battery, and all systems failing would ignore the fact that essential systems can stay powered by the battery.

When the Transformer Rectifier Unit fails, the normal path that converts generator output to DC for the essential bus is lost. The aircraft’s battery then supplies the essential DC bus, keeping critical equipment alive for a limited time. So components on the essential DC bus that are designed to run from the battery remain active. Avionics powered by external power won’t be guaranteed unless external power is connected, hydraulic pumps are typically not driven directly by the battery, and all systems failing would ignore the fact that essential systems can stay powered by the battery.