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

What is the primary purpose of the DC fuel pump?

1. To provide fuel to the engines only

2. To transfer fuel between tanks

3. To provide fuel to the APU on ground and for quick left engine relight

4. To maintain fuel pressure in all situations

The correct answer is: To provide fuel to the APU on ground and for quick left engine relight

The primary purpose of the DC fuel pump is to provide fuel to the Auxiliary Power Unit (APU) while the aircraft is on the ground, as well as to assist in quick relighting of the left engine if necessary. This dual function is crucial for ensuring that the APU has a continuous and reliable supply of fuel when the aircraft is stationary, allowing it to operate effectively and provide power for various ground services without the need to activate the main engines. Additionally, aiding in quick relight scenarios enhances safety and operational readiness, particularly in situations where the left engine may need to be restarted rapidly after shutdown or during an in-flight emergency. While transferring fuel between tanks and maintaining fuel pressure are important functions within an aircraft's fuel system, they are not the primary purpose of the DC fuel pump, making the option regarding the APU and engine relight the most accurate.