If you’ve spent any time around aviation, you’ve likely heard the term “V-speeds.” These critical performance speeds are used by pilots to ensure safe and efficient operation of an aircraft in various flight phases. From takeoff to landing, V-speeds provide a standardized set of guidelines for pilots. But what do these speeds mean, and why are they so important?

In this post, we’ll explore the most common V-speeds, their significance, and how pilots use them during flights.

What Are V-Speeds?

V-speeds are standardized terms used to define critical airspeeds for pilots to manage aircraft performance and ensure safety. Specific speeds vary by aircraft model and are detailed in the Aircraft Flight Manual.

The “V” comes from the French word “Vitesse,” meaning speed. These speeds are crucial because they help pilots operate their aircraft within safe boundaries. Each V-speed refers to a specific parameter or safety margin related to an aircraft’s operation, performance, or structural limits. Understanding and applying these speeds ensures safe and predictable behavior under varying conditions.

Why Are V-Speeds Important?

V-speeds are critical parameters in aviation as they define specific airspeeds for various phases of flight. Adhering to these speeds ensures the safety and efficiency of aircraft operations. By maintaining appropriate speeds, pilots can avoid exceeding structural limits, prevent stalls, and ensure adequate control during takeoff, landing, and various flight maneuvers. V-speeds are essential for maintaining aircraft integrity and passenger safety.

V-speeds provide pilots with a clear understanding of how an aircraft will perform under certain conditions. They account for factors such as aircraft weight, altitude, weather conditions, and flight configuration (e.g., flaps extended or retracted). By following V-speed guidelines, pilots can ensure they are operating within the aircraft’s performance envelope, which is crucial for maintaining safety.

List of V-Speeds and Their Meanings

V-speeds cover a wide range of critical speeds that are essential for flight safety and performance. Here’s a list of the most important V-speeds, categorized based on different phases of flight.

V1 – Decision Speed

V1 is a critical speed during takeoff — the speed by which the decision to continue or abort the takeoff must be made. Before reaching V1, the aircraft can safely stop on the runway. After passing V1, the pilot must continue the takeoff, even if an emergency arises, because the aircraft won’t have enough runway left to stop safely. V1 is calculated based on runway length, aircraft weight, and environmental factors like wind and runway conditions.

VR – Rotation Speed

VR is the speed at which the pilot initiates the takeoff rotation (lifting the nose). This is when the pilot pulls back on the control yoke to raise the nose of the aircraft and begin the climb. VR is vital for achieving a smooth and safe liftoff. It ensures that the aircraft has reached enough speed for the wings to generate sufficient lift. The pilot rotates the aircraft at VR to transition from ground roll to flight.

V2 – Takeoff Safety Speed

V2 represents the speed the aircraft must achieve by the time it reaches an altitude of 35 feet after takeoff. This speed ensures the aircraft has a sufficient climb rate, even in the event of an engine failure. V2 is especially important for twin-engine aircraft. It allows the plane to continue climbing with just one engine operating. After liftoff, pilots aim to maintain V2 until the aircraft reaches a safe altitude, ensuring stable flight with maximum safety.

VMCA – Minimum Control Speed with Critical Engine Inoperative (Air)

VMCA is the minimum airspeed at which an aircraft (typically a multi-engine aircraft) can be controlled when the critical engine (the engine whose failure would most adversely affect the aircraft’s handling and performance) is inoperative, and the remaining engine(s) are at maximum power. If the airspeed drops below VMCA during engine failure, the aircraft may become uncontrollable due to the loss of directional control and asymmetric thrust. Pilots ensure that during takeoff, climb, and other critical flight phases, the airspeed is maintained above VMCA to retain full control of the aircraft, especially in the event of an engine failure.

VMCG – Minimum Control Speed on Ground

VMCG is the minimum speed on the ground at which the aircraft can maintain directional control during the takeoff roll with one engine inoperative (typically the critical engine) and the other engine(s) at maximum thrust. Below this speed, the aircraft may veer off the runway. Below VMCG, there may not be enough aerodynamic force over the rudder to counter the asymmetric thrust from the operating engine(s), resulting in loss of directional control on the ground. VMCG is critical during the takeoff roll, and pilots need to ensure that if an engine failure occurs, the speed is above VMCG to allow for control without risking runway excursion.

VA – Maneuvering Speed

VA is the maximum speed at which an aircraft can withstand full, abrupt control inputs (e.g., a sharp turn or rapid pitch change) without suffering structural damage. VA is important for pilots to know when flying in turbulent conditions or when making aggressive maneuvers. At or below VA, the aircraft will stall before exceeding its design structural load limits, protecting it from overstressing. Exceeding VA can cause excessive stress on the wings, fuselage, or control surfaces, leading to potential structural failure. VA is not a fixed number; it changes with the aircraft’s weight. As the weight decreases, VA also decreases. This is because a lighter aircraft is more easily affected by sudden changes in control inputs.

VMO – Maximum Operating Speed

VMO is the maximum speed at which the aircraft can be safely operated under normal conditions. It is a structural limit that applies across all phases of flight, beyond which there is a risk of damaging the aircraft. VMO is often found in jets and high-performance aircraft and is usually expressed in knots indicated airspeed (KIAS). Exceeding VMO can lead to structural damage, excessive aerodynamic loads, or control difficulties. It’s primarily concerned with preventing overstress of the airframe during higher-speed flight.

VNO – Maximum Structural Cruising Speed

VNO is the maximum speed at which the aircraft can be flown safely in turbulent air without risking structural damage. It’s often referred to as the “normal operating speed” or “normal structural cruising speed.” VNO is generally used as a guideline when flying in rough air or turbulence. Above this speed, the aircraft should only be flown in calm air. Flying above VNO in turbulent air can cause excessive stress on the aircraft’s structure, so pilots reduce speed to VNO or lower during turbulence to avoid overstressing the airframe.

VMO vs. VNO
VMO is the absolute maximum operating speed in smooth air, while VNO is the speed limit for normal operation, particularly in turbulent or rough air. Exceeding VNO in turbulence can lead to structural stress, while exceeding VMO can lead to more immediate structural risks regardless of turbulence. VNO is more concerned with structural integrity in turbulence, whereas VMO is a hard limit that shouldn’t be exceeded under normal circumstances.

VREF – Landing Reference Speed

VREF is the approach speed used for landing, typically calculated as 1.3 times the stall speed in landing configuration. This speed provides a safe margin above the stall speed to ensure a stable approach and landing, allowing for small adjustments in pitch or power without risking a stall.

VAPP – Approach Speed

VAPP is the speed flown during the approach phase before reaching VREF. It accounts for variables such as wind gusts and weight, often incorporating a margin above VREF to allow for a safe approach in less-than-ideal conditions (such as gusty winds). VAPP is typically slightly higher than VREF to ensure adequate speed in case of fluctuations in airspeed. Pilots use VAPP when initially lining up for the approach to the runway. As they get closer to the runway threshold, they adjust speed to VREF for the final approach and landing.

VLE – Maximum Landing Gear Extended Speed

VLE is the maximum speed at which an aircraft can fly with the landing gear fully extended. Beyond this speed, the landing gear and its mechanisms may suffer structural damage due to the increased aerodynamic forces. Pilots must ensure that the aircraft’s airspeed stays below VLE whenever the landing gear is extended, such as during approach or when descending to land.

VLO – Maximum Landing Gear Operating Speed

VLO is the maximum speed at which the landing gear can be safely extended or retracted. Operating the landing gear (deploying or retracting) at speeds higher than VLO can cause damage to the landing gear mechanism. Pilots must operate the landing gear below VLO to avoid mechanical failures while extending or retracting the landing gear. This prevents overstressing the mechanical systems of the landing gear during extension or retraction.

VMCL – Minimum Control Speed in Landing Configuration

VMCL is the minimum speed at which the aircraft can be controlled during landing (in landing configuration) with one engine inoperative and the other engine(s) at maximum power. VMCL ensures that the aircraft remains controllable with asymmetric thrust when in the landing configuration (flaps and landing gear extended). If the speed falls below VMCL, the aircraft may lose control in yaw or roll due to the imbalance of power between engines. During approach and landing, particularly in engine-out situations, pilots must ensure the airspeed stays above VMCL to maintain control and avoid a loss of directional stability.

VFE – Maximum Flap Extended Speed

VFE is the maximum speed at which an aircraft can safely fly with flaps extended without damaging them. Flaps increase lift at lower speeds, but extending them too far at high speeds can cause structural damage. Exceeding VFE can damage the flaps or other parts of the aircraft. Pilots must ensure they do not extend flaps at speeds higher than VFE to avoid compromising the aircraft’s integrity.

VSO – Stall Speed in Landing Configuration

VSO is the stall speed when the aircraft is in its landing configuration—typically with full flaps extended and landing gear down. This is the lowest speed at which the aircraft can fly before stalling while configured for landing. Knowing VSO helps pilots avoid stalling during final approach and landing. Pilots ensure they maintain speeds above VSO when coming in for a landing to prevent unintentional stalls.

VS1 – Stall Speed in a Clean Configuration

VS1 is the stall speed in the aircraft’s clean configuration, meaning without flaps extended or landing gear down. This speed is higher than VSO due to the reduced drag in the clean configuration. VS1 helps pilots understand the minimum speed they need to maintain in standard flight to avoid a stall. During normal flight, pilots ensure they stay well above VS1 to maintain safe and controlled flight.

VS – Stall Speed

VS is the slowest speed at which the aircraft can fly in straight and level flight without stalling. Knowing VS helps pilots avoid unintentional stalls, especially during takeoff, landing, or slow-speed maneuvers. The stall speed can vary based on the aircraft’s configuration, weight, and external conditions such as air density and turbulence. VS typically refers to the stall speed in a “clean configuration” (flaps retracted, landing gear up). When the aircraft is configured for landing (e.g., flaps extended), the stall speed will be lower (VSO).

VNE – Never Exceed Speed

As the name suggests, VNE is the maximum speed that should never be exceeded under any circumstances, as it may cause structural failure. This is the absolute maximum speed an aircraft can handle without risking structural failure. Exceeding VNE could cause catastrophic failure of the aircraft. Pilots always keep the aircraft below VNE, especially during descents or in turbulence, to ensure flight safety.

Calculating V-Speeds

V-speeds are not static; they vary based on factors such as aircraft weight, altitude, and temperature. Most aircraft have charts or performance tables in their Pilot’s Operating Handbook (POH) or Aircraft Flight Manual (AFM) that allow pilots to calculate these speeds for different flight conditions.

For example, heavier aircraft require higher speeds for takeoff and landing, and altitude affects air density, which in turn impacts lift and drag. This is why pilots must calculate V-speeds specific to each flight rather than relying on standard values.

Regulatory Requirements for V-Speeds

Regulatory requirements for V-speeds are established by aviation authorities such as the Federal Aviation Administration (FAA) in the U.S. and the European Union Aviation Safety Agency (EASA) in Europe.

Aircraft manufacturers must demonstrate compliance with regulatory standards for V-speeds during the certification process. These speeds must be determined, documented, and provided in the Aircraft Flight Manual (AFM) or Pilot Operating Handbook (POH). The relevant regulations include:

  • FAA: Regulations found in 14 CFR Part 25 (for transport category airplanes) or Part 23 (for normal, utility, and commuter airplanes).
  • EASA: Requirements are covered under CS-25 (Certification Specifications for Large Aeroplanes) and CS-23 (Small Aeroplanes).

Specific sections cover the requirements for determining V-speeds:

  • V1 – Decision Speed, VR – Rotation Speed, V2 – Takeoff Safety Speed
    • FAA: 14 CFR Part 25.107 / Part 23.51
    • EASA: CS 25.107 / CS 23.51
  • VMCA – Minimum Control Speed with Critical Engine Inoperative (Air), VMCG – Minimum Control Speed on Ground
    • FAA: 14 CFR Part 25.149 / Part 23.149
    • EASA: CS 25.149 / CS 23.149
  • VA – Maneuvering Speed
    • FAA: 14 CFR Part 25.335(c) / Part 23.335(c)
    • EASA: CS 25.335(c) / CS 23.335(c)
  • VMO – Maximum Operating Speed, VNO – Maximum Structural Cruising Speed
    • FAA: 14 CFR Part 25.1505 / Part 23.1505
    • EASA: CS 25.1505 / CS 23.1505
  • VREF – Landing Reference Speed, VAPP – Approach Speed
    • FAA: 14 CFR Part 25.125 / Part 23.73
    • EASA: CS 25.125 / CS 23.73
  • VLE – Maximum Landing Gear Extended Speed, VLO – Maximum Landing Gear Operating Speed
    • FAA: 14 CFR Part 25.1515 / Part 23.1515
    • EASA: CS 25.1515 / CS 23.1515
  • VMCL – Minimum Control Speed in Landing Configuration
    • FAA: 14 CFR Part 25.149
    • EASA: CS 25.149
  • VFE – Maximum Flap Extended Speed
    • FAA: 14 CFR Part 25.1511 / Part 23.1511
    • EASA: CS 25.1511 / CS 23.1511
  • VSO – Stall Speed in Landing Configuration, VS1 – Stall Speed in a Clean Configuration, VS – Stall Speed
    • FAA: 14 CFR Part 25.103 / Part 23.49
    • EASA: CS 25.103 / CS 23.49
  • VNE – Never Exceed Speed
    • FAA: 14 CFR Part 23.1505
    • EASA: CS 23.1505

Note: VNE (Never Exceed Speed) is primarily defined in CS-23, which covers smaller aircraft. CS-25, which applies to larger aircraft, does not explicitly use the term “VNE”, but it does set various speed limits and structural design requirements that effectively establish the maximum safe operating speed for these aircraft.

For certain V-speeds, regulations require visible markings on cockpit instruments, particularly the airspeed indicator:

  • VNE: Marked with a red radial line to denote the never-exceed speed.
  • VNO: Marked with a green arc to indicate the normal operating range.
  • VS1 and VSO: Marked by white and green arcs for stall speeds in clean and landing configurations, respectively.

These markings help ensure that pilots can quickly reference key speed limits during flight.

AviationHunt Team

Our team at AviationHunt is a group of aviation experts and enthusiasts. We aim to provide aviation insights, technical notes, best aircraft maintenance practices, and aviation safety tips.