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

Why can only one backup generator operate at a time?

1. There is a limit on the number of backup generators

2. Only one generator is needed for power conversion

3. Systems are designed to run one at a time

4. There is only one converter available

The correct answer is: There is only one converter available

The reason why only one backup generator can operate at a time is due to the presence of only one converter that is used to change the generated power into a usable form. In many systems, generators produce electricity in a certain format that needs to be converted before it can be utilized by the aircraft systems. If there is only one converter, it implies that it can handle input from only one generator at any given time. Allowing multiple generators to operate simultaneously would lead to complexities in power management and could risk damaging the converter or the aircraft's electrical systems. When evaluating the other options, they do not accurately address the underlying mechanical and electrical design constraints. For instance, there are indeed situations where multiple backup generators could exist, but the capability to utilize them hinges on the ability to convert the power produced. Hence, the presence of a single converter clearly defines the operational limitation to one generator being able to work at a time.