Final answer:
Leading edge flaps on an aircraft extend or retract as the wings transition from cruising to either takeoff or landing position to adjust lift. They are similar to the adjustable blades of a wind turbine that rotate to maximize efficiency. Flaps ensure better aerodynamic control and are critical for safe flight operations.
Step-by-step explanation:
You asked about when the leading edge flaps of an airplane wing extend or retract. These flaps are part of the wing's mechanism to control the aircraft's lift and maneuverability during various phases of flight, especially takeoff and landing. The statement is referring to the flaps being deployed or retracted as the aircraft's wings pass through a certain position, which would likely be the transition from a cruising position to one optimized for takeoff or landing. This is when the aerodynamic requirements of the wing change and the flaps are used to alter the shape of the wing, maximizing lift at lower speeds.
The flaps on the wings allow for better control by the pilot and are essential for safe flight operations. In reference to the provided information, the blades mentioned that can be rotated on an axis for engaging the wind at different angles can be likened to how flaps work on an airplane wing. By adjusting the angle, the efficiency and responsiveness of the aircraft to pilot inputs can be varied. This is analogous to how wind turbine blades adjust to maximize their efficiency in capturing wind energy.