What is the first segment of climb defined from?

The first segment of climb is defined from takeoff until the landing gear is retracted. This phase is crucial as it reflects the aircraft's initial climb performance right after leaving the ground. During this segment, the aircraft is still very close to the runway and is transitioning from the takeoff roll into the climb. It is designed to ensure that the airplane not only gets airborne safely but also reaches a stable climb configuration before any further adjustments are made, such as retracting the landing gear.

This segment is characterized by specific performance metrics, including the rate of climb and the angle of ascent, which are vital for ensuring safety and efficiency during takeoff. Understanding this initial segment is important for pilots to adhere to safety protocols and avoid potential hazards immediately after takeoff.