What does a green dot indicate on the PFD during climb?

The green dot on the Primary Flight Display (PFD) during climb signifies the managed speed, which is an important reference for pilots during various phases of flight. Managed speed represents the optimal speed that the aircraft's flight management system (FMS) suggests under specific conditions, factoring in factors like altitude, aircraft configuration, and air traffic control requirements.

This managed speed is designed to ensure efficient fuel consumption while maintaining performance, and it adjusts automatically based on the aircraft's flight path. During climb, maintaining the green dot speed can enhance rate of climb and engine performance, as well as facilitate adherence to specific air traffic control commands.

In contrast, the other options pertain to different aspects of flight dynamics or specific operational speeds that don’t directly relate to the managed speed during climb. For example, best glide speed is relevant in scenarios such as engine failure, while minimum drag speed and standard operating speed pertain to different contexts in the aircraft's performance envelope. Recognizing the meaning of the green dot as managed speed is crucial for effective flight management and operational efficiency.