What does a clean configuration refer to in aviation?

A clean configuration in aviation refers to the absence of additional drag surfaces on the aircraft. This means that the aircraft is in a streamlined state, with landing gear retracted and flaps up or stowed. When an aircraft is in a clean configuration, it is optimized for efficient flight, reducing drag and improving fuel efficiency and performance.

The significance of maintaining a clean configuration is particularly crucial during phases of flight such as climb and cruise, where aerodynamic efficiency is paramount for performance and safety. Pilots are trained to ensure that the aircraft is cleaned up as quickly as possible after takeoff and before landing to minimize drag and optimize performance.

In contrast, the other options do not accurately describe what a clean configuration entails. For instance, being in a controlled descent focuses on the vertical maneuver of the aircraft rather than its aerodynamic state. Removing passengers and cargo pertains to weight management rather than configuration. Limiting aircraft speed to safe ranges is a matter of operational safety, not a description of the configuration itself.