What are V-speeds in aviation, and what do they mean?

V-speeds in aviation are standard labels for airspeed references used during take-off, climb, approach and landing, or to mark aircraft limits. For example, VS identifies a stall-related speed, VR is rotation speed and VNE is never-exceed speed. Some values are published limits; others are calculated for the flight.

For Aviation & Real-World Flying, including simulator use, the crucial distinction is that a V-speed is not automatically a target. It may be a minimum, a maximum, a calculated target, a decision point or a cue to perform an action. The letter V comes from vitesse, the French word for speed.

What is VS in aviation, and what does VS1 speed mean?

In a V-speed list, VS means stalling speed or the minimum steady flight speed at which the aircraft remains controllable under stated conditions.

An aircraft stalls when its wing exceeds the critical angle of attack, not simply because the indicator reaches a memorised number. Weight, configuration, load factor, power, turbulence and wing contamination can alter the observed stall speed or behaviour. A level turn raises load factor, so the aircraft can stall at a higher indicated speed than it does in straight-and-level flight.

Context matters because VS can also mean vertical speed on an autopilot panel, primary flight display or vertical-speed indicator. There it refers to climb or descent rate, normally in feet per minute, rather than a stall-related V-speed.

Main aviation V-speeds and their meanings

The main V-speeds cover stall references, take-off decisions, climb performance, landing targets and structural or configuration limits.

Not every aircraft uses every designation. A light single may publish VS0, VS1, VX, VY and configuration limits without having formal V1 or V2 figures. Transport aircraft rely heavily on calculated take-off and landing speeds, while manufacturers may define additional references for a particular type.

How do V1, VR and V2 work together?

V1 governs the reject-or-continue decision, VR tells the pilot when to rotate, and V2 is the take-off safety reference used during the initial multi-engine climb.

1. Before V1: a rejected take-off may be initiated when the briefed criteria require it and adequate stopping performance remains.
2. At V1: the first stopping action must begin no later than this speed to retain the calculated accelerate-stop basis. V1 is not a cue to begin considering the decision.
3. At VR: the pilot starts a controlled rotation towards the specified pitch attitude.
4. At V2: the aircraft has the planned take-off safety-speed reference for the initial climb, including the applicable engine-out case.

The numbers are calculated together but are not interchangeable. Our explanation of how 737-800 take-off and landing speeds are derived from aircraft and runway data gives a practical transport-aircraft example.

Are V-speeds fixed or calculated?

Some V-speeds are published aircraft limitations, while take-off, approach and other performance speeds must be selected or calculated for the actual conditions.

• Published limitations: VNE, VNO, VLE and VFE are commonly listed in the aircraft flight manual, pilot’s operating handbook, placards or instrument markings. VFE can vary by flap setting, and VLO can differ between extension and retraction.
• Scheduled performance speeds: VX, VY and VA may change with altitude, weight or configuration. The documentation may publish several values or provide a chart.
• Flight-specific speeds: V1, VR, V2, VREF and VAPP depend on factors such as weight, centre of gravity, flap setting, runway length and intersection, slope, wind, temperature, pressure altitude and runway condition.

Even an apparently fixed value belongs only to the stated aircraft variant, configuration and operating conditions. Modifications can change limits, and some aircraft use altitude-dependent schedules rather than one permanent red-line number. Never transfer a figure from a similar model without confirming that its documentation applies.

Are V-speeds IAS or groundspeed?

Most pilot-facing V-speeds are flown using indicated airspeed, normally expressed as knots indicated airspeed or KIAS, rather than GPS groundspeed.

Certification and performance material may define a speed in calibrated airspeed, while the operating handbook supplies an indicated value or conversion for cockpit use. Some older aircraft use miles per hour, so check the unit as well as the number. Reading 70 mph as 70 knots creates a significant error.

Groundspeed measures movement across the surface and changes with wind. It does not directly represent the airflow responsible for lift, stall and aerodynamic loads. Our guide to the difference between indicated airspeed and GPS groundspeed explains why a strong headwind or tailwind must not be applied to VS, VR or VREF as if it changed the aircraft’s aerodynamic speed.

Fast aircraft also observe Mach limits at altitude. The applicable maximum is whichever is reached first: VMO on the indicated-airspeed scale or MMO on the Mach display.

Finding the correct V-speed for an aircraft

The authoritative source is the documentation and performance data for the exact aircraft, variant, configuration and operating weight.

1. Identify the aircraft: confirm the model, engine, equipment standard and any modification that affects weight, aerodynamics or limitations.
2. Use the right source: for real flying, consult the approved flight manual, operating handbook, placards and operator data. In a simulator, use the documentation or performance tool supplied for the model being flown rather than an unrelated generic chart.
3. Match the conditions: select the correct weight, centre of gravity, flap setting, runway, weather and surface state. Transport performance calculations may also depend on thrust setting and aircraft-system configuration.
4. Check the speed’s purpose and unit: establish whether it is a target, minimum, maximum or action cue, and whether the source gives KIAS, KCAS, mph or Mach.
5. Recalculate after changes: update the figures if payload, fuel, runway, flap setting or weather changes. A speed bug only confirms what was entered; it does not prove the value is valid.

For a familiar light-aircraft example, our worked Cessna 172 V-speed chart explains VS0, VS1, VX, VY and the principal operating limits. Cessna 172 variants are not identical, so the matching handbook still takes precedence.

What do the airspeed indicator colour arcs show?

On a conventional general-aviation airspeed indicator, the colour arcs summarise the principal stall, flap and structural speed ranges.

• The white arc normally extends from VS0 to VFE and marks the flap operating range.
• The green arc normally extends from VS1 to VNO and marks the normal operating range.
• The yellow arc extends from VNO to VNE and is used only with caution in smooth air.
• The red line marks VNE.

These markings do not provide every speed: VX, VY, VA and take-off references usually come from documentation, a placard, checklist or electronic display. Our Cessna 172 cockpit and instrument guide shows where the airspeed arcs appear on a typical light-aircraft panel.

Common V-speed mistakes in flight simulators

Most simulator problems arise from using the correct label with the wrong number, condition, unit or pilot action.

• Rotating at V1: V1 is the take-off decision reference; VR is the cue to begin rotation.
• Using VS as vertical speed: VS means stall-related speed in a V-speed table, but it can mean vertical speed when shown as an autopilot or display mode.
• Copying another aircraft’s numbers: two visually similar variants can have different engines, weights, flap limits and performance.
• Reusing stale take-off data: changing payload, fuel, weather, runway or flap setting can invalidate V1, VR and V2.
• Flying GPS groundspeed: aerodynamic V-speeds normally use indicated airspeed, not the GPS read-out.
• Treating every speed as a target: VAPP may be a target, VR is an action cue, and VFE or VNE is a limit that must not be exceeded.
• Confusing VREF with VAPP: VAPP commonly includes an additive above VREF. Use the procedure defined for that aircraft rather than flying the two as interchangeable numbers.
• Treating VA as a safety shield: manoeuvring speed does not make repeated control reversals, combined inputs or severe turbulence harmless.
• Trusting an entered speed bug: an FMS or primary-flight-display marker can show a perfectly entered but incorrectly calculated value.

If a simulated aircraft reaches VR but refuses to rotate, simply adding more speed can consume the remaining runway and exceed tyre or flap limits. Check elevator and stabiliser trim, centre of gravity, gross weight, take-off flap configuration and control-axis calibration before blaming the published V-speed.