What is a main disadvantage of a gravity-fed fuel system?

A gravity-fed fuel system relies on the force of gravity to deliver fuel from the tank to the engine. While this system simplifies the design and avoids the need for complex fuel pumps, it has significant limitations, particularly in terms of flow control and performance at lower fuel levels.

When fuel levels are low, the gravitational force may not provide sufficient pressure to maintain a consistent flow to the engine, which can lead to fuel starvation and engine performance issues. This inconsistency poses challenges during critical phases of flight, such as takeoff and climb, where reliable fuel delivery is crucial for maintaining engine operation. Moreover, the lack of active flow control can hinder the aircraft's ability to manage fuel consumption efficiently, particularly in varied operating conditions.

Consequently, while gravity-fed systems can be simple and cost-effective in certain applications, their limitations in flow control and reliability at low fuel levels represent a significant disadvantage, particularly in aviation where safety and performance are paramount.