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read the speeds off. On the 727, V1
and VR are the same. Here are some:
Speed Meaning
MMO VMO for higher altitudes
VCEF See V1
VMO Max operating speed (at lower
altitudes), designed to prevent
excess damage from dynamic
pressure, so more relevant to high
speed aircraft. Equivalent of VNE.
Varies with altitude
VMU Max unstick speed
VNE Never Exceed speed, around 90%
of Dive Speed (VD). On a turbine,
equal to VMO or MMO.
VNO Normal Operations
VTOS Minimum speed positive climb
achieved in takeoff condition, one
or more engines out.
VLOF Lift off speed
VA Manoeuvring speed. The
maximum you can make abrupt,
full scale deflections of controls
without damage (about twice VS).
Not always the best speed for
entering turbulence (see below).
Valid only at gross weight. A 20%
decrease in weight needs a 10%
reduction in this.
VB Maximum gust or turbulence
penetration speed for turbines, at
Speed Meaning
penetration speed for turbines, at
least 10 kts below VA,
compensating for power used
delaying stall and windshear.
Lighter aircraft should be flown
slower, as stall speed decreases
in line with weight.
VC Cruise speed
VD Dive speed, normally at least 25%
higher than cruise speed.
VDF Demonstrated diving speed
VF Flap Speed
VFE Max speed flaps extended
VFO Max flap operating speed
VH Max level speed at max
continuous power.
VLE Max speed, gear extended
VLO Max gear operating speed
VLOF Lift off speed
VMCA Min Control Speed, for control in
air, with critical engine out and
other at takeoff thrust.
VMD Minimum Drag –induced drag
equals profile drag. It increases
with weight and lift.
VMD Minimum Drag –induced drag
equals profile drag.
V1 Takeoff Decision Speed, above
which the takeoff is continued, and
below it is abandoned, if an engine
fails. Technically, it is the critical
engine failure recognition speed,
also called Vcef. The distance
required to reject and stop will be
the same as that to accelerate to
V2 (below).
VR Rotation Speed, at which the
aircraft is rotated to the takeoff
attitude. VR must not be less than
V1 or 1.05 x VMC. It must also be
high enough to allow V2 to be
attained before reaching screen
height.
VREF Chosen speed for the approach
(ref speed), derived from 1.3 x VSO
(stall speed in landing
configuration), so it increases with
weight
VS Stall speed, or min steady
controllable speed in flight.
VSL As above, for a specific
configuration
Flight Planning 355
Speed Meaning
VSI Stall speed, clean, power off
VSO Stall Speed in landing config.
V2 Takeoff Safety Speed, or minimum
safe flying speed if you lose an
engine after takeoff, to be
achieved before screen height
(35'). Must be at least 20% more
than stall speed and 10% above
VMC. Weight is the main factor.
Should be calculated for each
landing for go-arounds.
V3 Flap retraction speed.
VX Best angle of climb
VY Best rate of climb
VYSE Best s/e rate of climb
VZRC Zero ROC – you cannot
accelerate, climb or turn, so must
reduce drag.
ETOPS
Essentially, Extended Range Twin
Operations covers twins on routes
more than one hours' flying time, at
the approved one engine cruise
speed (under standard conditions)
from a suitable aerodrome. A twinengined
turbojet must be able to
continue or divert where the flying
time is no longer than 180 minutes.
Higher maintenance standards are
naturally needed for all this, and
despatch of an ETOPS aircraft must
be carried out only by authorised
people. Aerodromes must allow you
to stop within the landing distance
available inside normal limits.
Services and facilities must also be
adequate, as must minima for the
expected runway. For an hour either
side of ETA, the latest forecast
weather conditions must equal or
exceed the planning minima for
alternates, and the forecast
crosswind component, including
gusts, must be less than the
maximum for landing, with one
engine out.
Some Questions
1. Given a distance from A to B of
480 nm, on a track of 090° with a
w/v of 270/60, and a TAS of 270
kts, find the distance of the critical
point from A, and the time it will
take to fly to it.
2. If the distance between A and B is
345 nm, the track is 140°, the w/v is
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Canadian Professional Pilot Studies2(95)
