What is V2 in aviation terms?

In aviation terms, V2 refers specifically to the minimum speed that an aircraft must maintain before reaching an altitude of 35 feet during takeoff, with one engine inoperative. This speed is critical for ensuring that the aircraft can safely climb away from the runway in the event of engine failure shortly after takeoff.

The primary function of V2 is to provide a necessary margin of safety when an engine fails, allowing a safe climb and ensuring that the aircraft can maintain controllability. This speed is calculated based on various factors, including the aircraft's weight, environmental conditions, and configuration at the time of departure.

Maintaining V2 during the takeoff phase is especially important for twin-engine aircraft, where the loss of an engine could significantly affect performance. The other answers relate to different flight phases or conditions, such as maximum climb speed after takeoff, sustained cruise speed, or landing approach speed, but they do not specifically address the critical safety parameter that V2 represents in the context of engine failure.