What is the common result of deploying spoilers?

Deploying spoilers on an aircraft primarily serves to decrease lift and induce drag, which is crucial for controlling descent and enhancing the aircraft's stability during landing. Spoilers are surfaces on the wings that can be raised to disrupt the airflow, thereby reducing the pressure over the wing and decreasing lift. This is particularly useful when an aircraft is approaching to land, as it allows for a steeper descent without gaining additional speed, helping pilots manage their approach more effectively.

The induced drag from spoilers also contributes to slowing the aircraft down. By intentionally creating drag, pilots can control their descent rate more efficiently and create a safer landing environment, especially in situations requiring quick reduction of altitude.

In contrast, increasing lift is contrary to the purpose of spoilers, which is to limit it. Enhancing fuel efficiency and improving navigation do not directly relate to the function of spoilers and their primary effects during flight operations.