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The human operator, the least reliable element of an aerodyne, but the most essential...!
Frank Caron (1991)


Last update:
26 September 2016

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Nice to know - V speeds
V1

Critical engine failure recognition speed
V1 is the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff with only the remaining engines. Any problems after V1 are treated as inflight emergencies.
In the case of a balanced field takeoff, V1 is the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance and the minimum speed at which the takeoff can be continued and achieve the required height above the takeoff surface within the takeoff distance. In this context, V1 is the takeoff decision speed.

Other presentation: V1 is the maximum speed where an action must occur to stop the airplane on the runway and the minimum speed at which the takeoff can be continued following the recognition of an engine failure and achieve the required height above the takeoff surface.

Other presentation from Boeing: It was determined in 1992 that the existing definition of V1 might have caused confusion because they did not make it clear that V1 is the maximum speed at which the flight crew must take the first action to reject a takeoff. As a result, the FAA has changed the definition of V1 in FAR Part 1 to read as follows:

  • V1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speedbrakes) to stop the airplane within the accelerate-stop distance and
  • V1 also means the minimum speed in the takeoff, following a failure of an engine at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.
V1 (MCG) or VMCG
Minimum Control Speed (GROUND)
The speed which correspond to an engine failure at VMCG plus the speed gained during one second following the engine failure.
It is the V1 minimum speed.
V2
Take Off safety speed
Also called takeoff screen speed, the minimum speed in the second segment of a climb following an engine failure.
V2 is the normal engine inoperative initial climb speed.
Minimum V2 must be equal to or greater than 1.13 VS1g and 1.1 VMCA
V2min
Minimum takeoff safety speed
V3 Steady initial climb speed with all engines operating
V4
Steady climb speed with all engines operating to be achieved by 400 ft gross height
VA
Design maneuvering speed
It is a
stalling speed at the maximum legal G-force and hence the maximum speed at which abrupt, full deflection, control inputs will not cause the aircraft to exceed its G-force limit).
Maneuvering speed is limited by aircraft structural characteristics.
VB
Design speed for maximum gust intensity
VBE
Best endurance speed
The speed that gives the greatest airborne time for fuel consumed. This may be used when there is reason to remain aloft for an extended period, such as waiting for a forecast improvement in weather on the ground.
VBG
Best power-off glide speed
The speed that provides maximum lift-to-drag ratio and thus the greatest gliding distance available.
Vc
Design cruising speed
Vclmax
Max coefficient of lift speed
VD
Design diving speed
Usually 1.4 × VNO.
VDF/MDF
Demonstrated flight diving speed
Vdmin
Minimum drag
VEF
Velocity Engine Failure
The Calibrated Airspeed at which the critical engine is assumed to fail during takeoff.
VF
Design flap speed
VFC/MFC
Maximum speed for stability characteristics
VFE
Maximum flap extended speed
Different maximum speeds may be specified for partial flap extension.
Top of white arc on many airspeed indicators.
VFEN Next Flap Extension Speed or Predictive Vfe at Next Flap/Slat Position
VFTO
Final takeoff speed
VH
Maximum speed in level flight with maximum continuous power.
Vimd or Vmd
Minimum drag
Vimp
Minimum power
VLE
Maximum landing gear extended speed
The maximum speed at which the aircraft may be flown with the landing gear extended
VLE is always higher than VLO
VLO
Maximum landing gear operating speed
The maximum speed at which the aircraft may be flying while raising or lowering the gear.
VLO is always lower than VLE
VLOF
Lift-off speed
VLS Lowest Selectable Speed
VM or VMAN Recommended Maneuvering Speed
VMAX Maximum Operating Speed
VMBE
Maximum Brake Energy speed
The maximum speed at which the wheel brakes have demonstrated the ability to absorb the energy required to stop the airplane for the takeoff conditions.
VMC
Minimum control speed with the critical engine inoperative
VMCA Minimum Control Speed (AIR)
VMCG or V1 (MCG) see V1 (MCG) or VMCG
Vmcl
Minimum control speed, approach and landing
VMD Minimum Drag
Vme
Maximum endurance
VMIN  Minimum Operating Speed
VMO/MMO
maximum operating limit speed.
Vmp
Minimum power
Vmr
Maximum range
VMU
Minimum unstick speed.
Vnd
Maximum structural cruising speed
VNE
Never-exceed speed
Red line and top of yellow arc on many airspeed indicators.
VNO Maximum structural cruising speed
The maximum speed to be used in turbulent conditions or can refer to the velocity of normal operation.
This speed is specific to the aircraft model.
VNO is specified as the upper limit of the green arc and bottom of yellow arc on many airspeed indicators. The range above VNO is marked on the airspeed indicator as a yellow arc from VNO to the VNE. The yellow arc is a caution, as speeds in this region may add dangerous stress to the aircraft, and are only to be used in smooth air when no turbulence or abrupt control inputs are expected.
Vp
Aquaplaning speed
VR
Rotation speed
The speed of an aircraft at which the pilot initiates rotation to obtain the scheduled takeoff performance. It must be greater or equal to the V1 speed.
VR >= 1.05 VMCA
Vra
Rough air speed
VREF

Reference landing approach speed
Speed (in calm air) at the landing screen height of 50 ft. Often used by pilots as a base from which to calculate speeds to be used during landing, and calculated as a margin over the stall speed; usually 1.3 × VS0.

VS
Stall speed
The stalling speed or the minimum steady flight speed at which the airplane is controllable. Usually synonymous with VS1, stall speed in a specified configuration.
Bottom of green arc on many airspeed indicators.
VS0
The stalling speed or the minimum steady flight speed in the landing configuration.
Bottom of white arc on many airspeed indicator.
VS1
The stalling speed or the minimum steady flight speed obtained in a specific configuration (usually a configuration "clean" of flaps, landing gear and other sources of drag).
VS1g
One g stall speed
VSR
Reference stall speed
VSR0
Reference stall speed in the landing configuration
VSR1
Reference stall speed in a specific configuration
VSS Stick Shaker speed
Vsse
Safe single engine speed
VSW
Speed at which onset of natural or artificial stall warning occurs
Vt
Threshold speed
Vtmax
Max threshold speed
VX
Speed for best angle of climb
This provides the best altitude gain per unit of horizontal distance, and is usually used for clearing obstacles during takeoff.
VXSE or VXE
Speed for best angle climb with the critical engine inoperative on multi engine aircraft
VY
Speed for best rate of climb
This provides the best altitude gain per unit of time.
VYSE or VYE
Speed for best rate of climb with the critical engine inoperative on multi engine aircraft

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