VFe

Vfe is an airspeed limit used in aviation to indicate the maximum indicated airspeed at which a given flap configuration may be safely extended. The term stands for maximum flap extension speed and is published by aircraft manufacturers in the flight manual and the aircraft’s aeronautical documentation. For most airplanes, each flap setting has its own Vfe value, meaning flap positions such as 10 degrees or 30 degrees will have corresponding Vfe limits.

Vfe is a structural and aerodynamic limit. Exceeding the Vfe for the current flap configuration can impose excessive loads, causing flap hardware damage, improper deployment, or adverse handling characteristics. Therefore, pilots are required to operate with flaps within the approved speeds and retract or adjust flaps if airspeed approaches or exceeds the limit. Vfe is typically well below the overall maximum operating speed (Vno) and/or the high-speed redline (Vne), and it is often lower at heavier weights or in configurations with more extended flaps.

Variations in Vfe can occur with changes in weight, center of gravity, altitude, temperature, and aircraft condition. The exact values are aircraft-specific and can differ between models and series. Practitioners consult the flight manual for the precise Vfe values for each flap setting and for any notes on limitations during takeoff, approach, and landing phases.

Related operating limits include Vmo/MMO (maximum operating/mach numbers), Vs (stall speed), Vno (maximum structural cruising speed), and Vne (never-exceed speed). Vfe is one component of a broader set of performance and structural limits designed to ensure safe flap operation.