How is the maximum speed at which flaps can be extended identified on an airspeed indicator?

The maximum speed at which flaps can be extended is indicated by the flap operating speed upper limit, commonly referred to as VFE. This speed is critical because it denotes the maximum airspeed at which the flaps can safely be deployed without risking damage to the aircraft's structure or compromising performance.

When a pilot extends the flaps, they change the aerodynamic characteristics of the aircraft, increasing lift but also introducing additional drag. Exceeding VFE while extending the flaps could lead to structural failure or undesirable flight characteristics, therefore understanding this limit is essential for safe aircraft operation.

While the other terms relate to specific aspects of flight as well, they do not designate the maximum safe speed for flap extension:

• The flap operating speed lower limit, VSO, marks the stall speed in a specified configuration and does not relate to flap extension speeds.

• Normal structural cruising speed, VNO, is the maximum speed for normal operations without exceeding structural limits but does not address flap operations specifically.

• Never-exceed speed, VNE, is a limit for maximum speed in the aircraft's operating envelope and, while being critical, does not indicate flap extension parameters.

Thus, recognizing VFE is essential for the safe operation of the aircraft during maneuvers