The Fourth Climb Segment begins at what event?

• A. Flaps are retracted
• B. Gear up
• C. VFTO established
• D. Slats extended

Answer: (A)

Climb segments are defined by changes in aircraft configuration that affect lift and drag. When flaps are retracted, the airplane moves from a flaps-down takeoff/climb setup to a clean configuration, which reduces drag and allows a higher climb rate. This change marks a natural boundary for the Fourth Climb Segment, since the performance and handling assumptions used for that segment are based on the clean configuration.

Slats extended would occur earlier during takeoff and descent or early climb, so it isn’t the boundary for this segment. Gear up is related to retracting the landing gear, which typically happens after the initial climb and flap retraction but is not the designated boundary for the Fourth Climb Segment. VFTO established is a speed reference, not a configuration change that defines climb segments.