FAA Aircraft Dispatcher Practice Exam

How are primary flight controls operated if both the A and B systems fail?

1. Using manual controls

2. Using only the emergency system

3. They will be inoperative

4. With auxiliary power only

The correct answer is: Using manual controls

Primary flight controls are typically designed with multiple layers of redundancy to ensure safety and operational capability even in the event of a system failure. If both the A and B systems fail, the most reliable method of control reverts to manual controls. This allows pilots to maintain the ability to maneuver the aircraft directly, utilizing mechanical linkages that remain operable despite electronic or hydraulic system failures. In aviation, there are often backup systems in place for managing primary flight controls. However, if those backup systems also fail, relying on manual controls ensures the highest level of control available. This approach highlights the fundamental design intention in aircraft, prioritizing user input and control in critical situations. Using only the emergency system is not the main mode of control in the event of complete system failure, as emergency systems often serve as a backup rather than a primary control mechanism. The other provided choices do not account for the need for direct pilot interaction with the aircraft controls, which is why relying on manual controls is essential in this circumstance.