V1 |
The speed beyond which the takeoff should no longer
be aborted. |
V2 |
Speed at which the
aircraft may safely be climbed with one engine
inoperative. |
V2min |
Minimum takeoff
speed. |
V3 |
Flap retraction speed. |
V4 |
Steady initial climb
speed. The all engines operating take-off climb
speed used to the point where acceleration to flap
retraction speed is initiated. Should be attained by
a gross height of 400 feet. |
VA |
Design maneuvering
speed. This is the speed above which it is unwise to
make full application of any single flight control
(or "pull to the stops") as it may generate a force
greater than the aircraft's structural limitations. |
Vat |
Indicated airspeed at threshold, which is usually
equal to the stall speed VS0 multiplied
by 1.3 or stall speed VS1g multiplied by
1.23 in the landing configuration at the maximum
certificated landing mass, though some manufacturers
apply different criteria. If both VS0 and
VS1g are available, the higher resulting
Vat shall be applied. Also called
"approach speed". |
VB |
Design speed for maximum gust intensity. |
VC |
Design cruise speed, used to show compliance with
gust intensity loading. |
Vcef |
See V1; generally used in documentation
of military aircraft performance. |
VD |
Design diving speed, the highest speed planned to be
achieved in testing. |
VDF |
Demonstrated flight diving speed, the highest actual
speed achieved in testing. |
VEF |
The speed at which the
critical engine
is assumed to fail during takeoff. |
VF |
Designed flap speed. |
VFC |
Maximum speed for stability characteristics. |
VFE |
Maximum flap extended speed. |
VFTO |
Final takeoff speed. |
VH |
Maximum speed in level flight at maximum continuous
power. |
VLE |
Maximum landing gear extended speed. This is the
maximum speed at which a retractable gear aircraft
should be flown with the landing gear extended. |
VLO |
Maximum landing gear operating speed. This is the
maximum speed at which the landing gear on a
retractable gear aircraft should be extended or
retracted. |
VLOF |
Lift-off speed. |
VMC |
Minimum control
speed. Mostly used as the minimum control
speed for the takeoff configuration (takeoff flaps).
Several VMCs exist for different flight
phases and airplane configurations: VMCG,
VMCA, VMCA1, VMCA2,
VMCL, VMCL1, VMCL2.
Refer to the
minimum control speed article for a thorough
explanation. |
VMCA |
Minimum control
speed in the air.
The minimum
speed at which steady straight flight can be
maintained when an engine fails or is inoperative
and with the corresponding opposite engine set to
provide maximum thrust, provided a small (3° - 5°)
bank angle is being maintained away from the
inoperative engine and the rudder is used up to
maximum to maintain straight flight. The exact
required bank angle for VMCA to be valid
should be provided by the manufacturer with
VMC(A)
data; any other bank angle results in a higher
actual VMC(A). Refer to the
minimum control
speed article for a description of
(pilot-induced) factors that have influence on VMCA.
VMCA is also presented as VMC
in many manuals. |
VMCG |
Minimum control
speed on the ground is the lowest speed at
which the takeoff may be safely continued following
an engine failure during the takeoff run. Below VMCG,
the throttles need to be closed at once when an
engine fails, to avoid veering off the runway. |
VMCL |
Minimum control
speed in the landing configuration with one
engine inoperative. |
VMO |
Maximum operating limit speed. |
VMU |
Minimum un-stick speed. |
VNE |
Never exceed speed. |
VNO |
Maximum structural cruising speed or maximum speed
for normal operations. |
VO |
Maximum operating maneuvering speed. |
VR |
Rotation
speed. The speed at which the pilot begins to apply
control inputs to cause the aircraft nose to pitch
up, after which it will leave the ground. |
Vrot |
Used instead of VR (in discussions of the
takeoff performance of military aircraft) to denote
rotation speed in conjunction with the term
Vref (refusal speed). |
VRef |
Landing reference speed or threshold crossing speed.
(In discussions of the takeoff performance of
military aircraft, the term Vref stands
for refusal speed. Refusal speed is the
maximum speed during takeoff from which the air
vehicle can stop within the available remaining
runway length for a specified altitude, weight, and
configuration.) Incorrectly, or as an abbreviation, some
documentation refers to Vref and/or Vrot
speeds as "Vr." |
VS |
Stall speed or minimum steady flight speed for which
the aircraft is still controllable. |
VS0 |
Stall speed or minimum flight speed in landing
configuration. |
VS1 |
Stall speed or minimum steady flight speed for which
the aircraft is still controllable in a specific
configuration. |
VSR |
Reference stall speed. |
VSR0 |
Reference stall speed in landing configuration. |
VSR1 |
Reference stall speed in a specific configuration. |
VSW |
Speed at which the stall warning will occur. |
VTOSS |
Category A rotorcraft takeoff safety speed. |
VX |
Best
angle of climb. |
VY |
Best
rate of climb. |
VBE |
Best endurance speed the speed that gives the
greatest airborne time for fuel consumed. |
VBG |
Best power-off glide speed the speed that provides
maximum lift-to-drag ratio and thus the greatest
gliding distance available. |
VBR |
Best range speed the speed that gives the greatest
range for fuel consumed often identical to Vmd. |
VFS |
Final segment of a departure with one powerplant
failed. |
Vimd |
Minimum drag. |
Vimp |
Minimum power. |
VLLO |
Maximum landing light operating speed for aircraft
with retractable landing lights. |
Vmbe |
Maximum brake energy speed. |
Vmd |
Minimum drag (per lift) often identical to VBR.
(alternatively same as Vimd. |
Vmin |
Minimum speed for instrument flight (IFR) for
helicopters. |
Vmp |
Minimum power. |
Vms |
Minimum sink speed at median wing loading - the
speed at which the minimum descent rate is obtained.
In modern gliders, Vms and Vmc
have evolved to the same value. |
Vp |
Aquaplaning speed. |
VPD |
Maximum speed at which whole-aircraft parachute
deployment has been demonstrated. |
Vra |
Rough air speed (turbulence penetration speed). |
VSL |
Stall speed in a specific configuration. |
Vs1g |
Stall speed at 1g load factor. |
Vsse |
Safe single engine speed. |
Vt |
Threshold speed. |
VTD |
Touchdown speed. |
VTGT |
Target speed. |
VTO |
Take-off speed. (see also VLOF). |
Vtocs |
Take-off climbout speed (helicopters) |
Vtos |
Minimum speed for a positive rate of climb with one
engine inoperative. |
Vtmax |
Max threshold speed. |
Vwo |
Maximum window or canopy open operating speed. |
VXSE |
Best angle of climb speed with a single operating
engine in a light, twin-engine aircraft
the speed that provides the most altitude gain per
unit of horizontal distance following an engine
failure, while maintaining a small bank angle that
should be presented with the engine-out climb
performance data. |
VYSE |
Best rate of climb speed with a single operating
engine in a light, twin-engine aircraft
the speed that provides the most altitude gain per
unit of time following an engine failure, while
maintaining a small bank angle that should be
presented with the engine-out climb performance
data. |
VZRC |
Zero rate of climb speed in a twin-engine aircraft. |