PSA Airlines Canadair Regional Jet Systems (PSA-CRJ) Practice Exam

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Prepare for the PSA Airlines Canadair Regional Jet Systems Exam. Study with comprehensive flashcards and multiple choice questions, each with hints and explanations. Get ready to excel!

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What happens if the DC Service switch is left on overnight?

The APU battery gets charged
The APU battery is depleted
The main battery gets charged
No effect on the battery

The correct answer is: The APU battery is depleted

Leaving the DC Service switch on overnight depletes the APU battery. The DC Service switch is designed to supply power to various aircraft systems when the engines or auxiliary power unit (APU) are not running. If this switch is left on for an extended period, such as overnight, it draws power from the APU battery to maintain the necessary systems. Since the APU battery is not being charged during this time—without the APU running to replenish its charge—the battery gradually loses its charge and may become depleted. This understanding is critical for operational safety and ensuring that the aircraft's systems can function correctly when needed. Proper management of auxiliary power systems is essential to prevent situations where the battery power is insufficient for starting the APU or running critical systems.