General Authority of Civil Aviation (GACA) Aeronautical Information Publication (AIP) Practice Exam

In which situation will the backup generator activate?

1. When all main generators are operational

2. When at least one main generator or APU is offline

3. When there is no fuel supply

4. When maintenance is performed

The correct answer is: When at least one main generator or APU is offline

The backup generator is designed to ensure a continuous power supply in critical situations, particularly when there may be a loss of normal power sources. The correct scenario for the activation of the backup generator occurs when at least one of the main generators or the Auxiliary Power Unit (APU) is offline. This means that the backup generator serves its purpose of providing power when the primary sources are compromised, thereby enhancing safety and reliability in flight operations. In contrast, the first option indicates that the backup generator would activate when all main generators are fully operational, which undermines the need for a backup system. The options regarding a lack of fuel supply or maintenance-related scenarios do not directly correlate with the need for a backup generator's activation, as they pertain to operational issues beyond the electrical power system's immediate response requirements. The focus of a backup generator is primarily on maintaining power availability in instances where regular power sources fail.