What is the function of an emergency power unit?

The primary function of an emergency power unit is to provide emergency electrical power. This system is crucial for maintaining essential functions in an aircraft during an electrical failure or when the main power supply is compromised. Emergency power ensures that vital systems, such as navigation, communication, and flight controls, remain operational, enabling the crew to manage emergencies effectively and maintain safety during flight.

While starting aircraft engines, assisting in navigation, and controlling cabin pressure are all important aspects of aircraft systems, these functions are typically managed by separate systems and do not fall under the duties of the emergency power unit. Therefore, the correct focus on the necessity of keeping critical electrical systems running in the event of emergencies highlights why the response regarding providing emergency electrical power is accurate.