Airspeed Limitations, Manoeuvring Speeds and Performance

Alphabet Soup?
Aviation Acronyms can seem like Alphabet Soup!

With Airspeeds and V-Speeds, there are dozens of Aviation Acronyms for the student pilot to learn and remember.

Your Aviation Acronym Decoder begins with some talk about Velocity.

V is for Velocity
Important aviation Airspeeds are identified and defined using standard terms. Scientists and Engineers refer to Speed as Velocity. Therefore these standard Airspeeds (Velocity) are defined as V-Speeds where the V is for Velocity.

Aircraft designers and manufacturers perform flight tests to help determine performance limitations of aircraft. The resulting flight test data is used to help determine specific best practice speeds for safe operation of the aircraft. Recommended Velocity Speeds (V-Speeds) are published and these airspeeds are relied on for best performance and safety of the aircraft. Pilots should be knowledgeable about the published V-Speeds for each type and configuration of aircraft they fly.

Pilot’s Operating Handbook
Pilots should consult the Pilot’s Operating Handbook, or POH, for the aircraft they fly. These important V-Speeds will be published in the POH (Information Manual) for their specific Aircraft type and model. 

Airspeed Indicator
Fortunately, the Airspeed Indicator in your airplane will have some of the more important V-Speeds highlighted or emphasized directly on the dial of the flight instrument. This helps the pilot to visually recognize these V-Speeds and easily determine how close they are to the V-Speeds while in flight.

General aviation aircraft depict the most commonly-used and most safety-critical airspeeds or V-Speeds on the Airspeed Indicator. These are displayed as color-coded arcs and lines located on the face of an aircraft’s airspeed indicator flight instrument.

White, Green, Yellow and Red
You will notice the colour-coded bands or arcs on the Airspeed Indicator. Pictured is a sample ‘Steam Gauge’ Airspeed Indicator. Let’s take a closer look, to determine some of these important V-Speeds. Remember, this is just an example, and the V-Speeds will differ based on the exact type, model and configuration of aircraft you fly.

The White Arc
The Flaps Operating Range is denoted by the White Arc. Flaps may only be used within this range of speeds.

Vs0
The beginning of the White Arc is the power off Stalling Speed with gear and full flaps extended, also known as Vs0. The Vs0 (Velocity Stall 0) represents the Stalling Speed of the aircraft configured for landing. (i.e. Gear Down and Flaps Down) An easy way to remember this is to think of the Velocity (V) of Stall (s) with everything hanging Out (0) or Vs0.

Vs and Vs1
Now that you are familiar with Vs0, it’s easy to remember Vs1. The beginning of the Green Arc is the power off Stalling Speed with the Gear and Flaps retracted. Vs is the Velocity (V) of the Stall (s), or minimum steady flight speed for which the aircraft is still controllable. As a memory aid, Vs1 is the Velocity (V) of the Stall (s) with everything Inside (1 looks like the letter i for inside). This is the Stall speed or minimum steady flight speed for which the aircraft is still controllable in a specific configuration.

The lower ends of the Green Arc and the White Arc depict the stalling speed with wing flaps retracted (Vs1), and stalling speed with wing flaps fully extended (Vs0), respectively. These Vs (Velocity of Stall) speeds are the stalling speeds for the aircraft at its maximum weight.

Vfe
The Top of the White Arc depicts the Maximum Flap Extended Speed. This is referred to as Vfe for Velocity (V) with Flaps (f) Extended (e). This represents the maximum airspeed at which you may extend the flaps, or fly with them extended. The flaps may not be used above this range (White Arc) or possible structural damage may occur to the aircraft.

The Green Arc
The Green Arc on the Airspeed Indicator depicts the normal operating airspeed range. As we have learned, Vs is the Velocity (V) of the Stall (s) and the Vs or Vs1 speed is denoted by the beginning of the Green Arc. At the top end of the Green Arc, is the Vno.

Vno
As the Green Arc is the Normal Operating Range, the top of the green arc is the Velocity (V) of Normal (n) Operations (o) or Vno. This is the maximum structural cruising speed. Operation of the Aircraft at the Vno speed, and lower, is within the certified range for operations within gusts. The aircraft is certified to withstand substantial wind gusts without experiencing structural damage. Operations above Vno move into the Yellow Arc on the Airspeed Indicator. Do not exceed Vno, except in Smooth Air, and only with caution.

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