What is the role of speed brakes in an aircraft?

Speed brakes play a crucial role in the performance and handling of an aircraft, primarily functioning to reduce speed during various phases of flight. When deployed, speed brakes create additional drag, which helps slow the aircraft down effectively without the need for excessive use of the wheels' brakes. This is particularly useful during descent and landing, as it allows pilots to maintain control of the aircraft's speed while managing descent rates and approach profiles.

In contrast, increasing altitude is not a function of speed brakes; their purpose is specifically to slow down the aircraft. Similarly, while speed brakes can assist in the landing phase, they do not directly improve fuel efficiency; in fact, their deployment usually results in increased drag, which generally leads to higher fuel consumption. Lastly, speed brakes do not stabilize the aircraft in flight; stability is achieved through proper control of lift and weight balance, while speed brakes are a tool for speed management.