This decreases the lift the wing produces at the tip to improve
the stall characteristics of the wing. Also called washout.
Two-stroke engine. A simple form of reciprocating engine
that completes its operating cycle in two strokes of its
piston, one down and one up. Two-stroke-cycle engines are
inefficient in their use of fuel, but their simplicity makes
them popular for powering light-sport aircraft and ultralight
vehicles where light weight and low cost are paramount.
Ultralight. A single person only vehicle as defined by 14
CFR section 103.1.
Uncontrolled airspace. Class G airspace that has not been
designated as Class A, B, C, D, or E. It is airspace in which
air traffic control has no authority or responsibility to control
air traffic; however, pilots should remember there are VFR
minimums which apply to this airspace.
Unicom. A nongovernment air/ground radio communication
station which may provide airport information at public use
airports where there is no tower or automated flight service
station.
Unusable fuel. Fuel that cannot be consumed by the engine.
This fuel is considered part of the empty weight of the
aircraft.
Useful load. The weight of the pilot, copilot, passengers,
baggage, usable fuel, and drainable oil. It is the basic empty
weight subtracted from the maximum allowable gross weight.
This term applies to general aviation aircraft only.
Unstabilized approach. The final approach of an aircraft that
has not achieved a stable rate of descent or controlled flight
track by a predetermined altitude, usually 500 feet AGL.
Unusual attitude. An unintentional, unanticipated, or
extreme aircraft attitude.
Useful load. The weight of the pilot, copilot, passengers,
baggage, usable fuel, and drainable oil. It is the basic empty
weight subtracted from the maximum allowable gross weight.
This term applies to general aviation aircraft only.
User-defined waypoints. Waypoint location and other data
which may be input by the user, this is the only GPS database
information that may be altered (edited) by the user.
Upwind Leg. A flight path parallel to the landing runway in
the direction of landing.
Vapor lock. A problem that mostly affects gasoline-fuelled
internal combustion engines. It occurs when the liquid fuel
changes state from liquid to gas while still in the fuel delivery
system. This disrupts the operation of the fuel pump, causing
loss of feed pressure to the carburetor or fuel injection system,
resulting in transient loss of power or complete stalling.
Restarting the engine from this state may be difficult. The fuel
can vaporise due to being heated by the engine, by the local
climate, or due to a lower boiling point at high altitude.
VASI. See visual approach slope indicator.
Vehicle. Manmade means of transportation; an ultralight
aircraft (not a light-sport aircraft).
Venturi. A specially shaped restriction in a tube designed
to speed up the flow of fluid passing through in accordance
with Bernoulli’s principle. Venturis are used in carburetors
and in many types of fluid control devices to produce a
pressure drop proportional to the speed of the fluid passing
through them.
Venturi Effect. The effect of Bernoulli’s principle, which
states that the pressure of a fluid decreases as it is speeded up
without losing or gaining any energy from the outside.
Verified. Confirmation of information or configuration
status.
Vertical axis (yaw). An imaginary line passing vertically
through the center of gravity of an aircraft. The vertical axis
is called the z-axis or the yaw axis.
Vertical speed indicator (VSI). An instrument that uses
static pressure to display a rate of climb or descent in feet
per minute. The VSI can also sometimes be called a vertical
velocity indicator (VVI).
Vertigo. A type of spatial disorientation caused by the
physical senses sending conflicting signals to the brain.
Vertigo is especially hazardous when flying under conditions
of poor visibility and may cause pilot incapacitation, but may
be minimized by confidence in the indication of the flight
instruments.
VFR. See visual flight rules.
VFR Terminal Area Charts . Charts designated to depict
Class B airspace in greater detail and greater scale than
sectional charts.
Vg diagram. A chart that relates velocity to load factor. It
is valid only for a specific weight, configuration and altitude
and shows the maximum amount of positive or negative lift
the airplane is capable of generating at a given speed. Also
shows the safe load factor limits and the load factor that the
aircraft can sustain at various speeds.
VNE. See never-exceed speed.
VNO. See maximum structural cruising speed.
VS. See stalling speed.
VX. See best angle-of-climb speed.
VY. See best rate-of-climb speed.
Victor airways. Airways based on a centerline that extends
from one VOR or VORTAC navigation aid or intersection,
to another navigation aid (or through several navigation aids
or intersections); used to establish a known route for en route
procedures between terminal areas.
Visual approach slope indicator (VASI). A visual aid of
lights arranged to provide descent guidance information
during the approach to the runway. A pilot on the correct
glideslope will see red lights over white lights.
Visual flight rules (VFR) . Rules in the Code of Federal
Regulations that govern the procedures for conducting flight
under visual conditions.
Visual meteorological conditions (VMC). Meteorological
conditions expressed in terms of visibility, distance from
cloud, and ceiling meeting or exceeding the minimums
specified for VFR.
VSI. See vertical speed indicator.
Wake turbulence. Wingtip vortices that are created when
an aircraft generates lift. When an aircraft generates lift, air
spills over the wingtips from the high pressure areas below
the wings to the low pressure areas above them. This flow
causes rapidly rotating whirlpools of air called wingtip
vortices or wake turbulence.
Warm front. The boundary area formed when a warm air
mass contacts and flows over a colder air mass. Warm fronts
cause low ceilings and rain.
Warning area. An area containing hazards to any aircraft
not participating in the activities being conducted in the
area. Warning areas may contain intensive military training,
gunnery exercises, or special weapons testing.
Waypoint. A designated geographical location used for route
definition or progress-reporting purposes and is defined in
terms of latitude/longitude coordinates.
Washout. The design of the WSC wing in which a wing
is twisted so its angle of attack is less at the tip than at the
root. Washout decreases the lift the wing produces at the tip
to improve the stall characteristics of the wing. Also called
twist.
Washout strut. The structural member attached to the
leading edges which holds the tip twist for the wing at low
or negative angles of attack.
WCA. See wind correction angle.
Weather briefing. Means for pilots to gather information
vital to the nature of the flight from a flight service station
specialist.
Weathervane. The tendency to point into the wind.
Weight. A measure of the heaviness of an object. One of the
four main forces acting on an aircraft. The force by which a
body is attracted downward toward the center of the Earth
(or another celestial body) by gravity. Weight is equal to
the mass of the body times the local value of gravitational
acceleration.
Weight-Shift Control Aircraft. Powered aircraft with a
framed pivoting wing and a fuselage controllable only in
pitch and roll by the pilot’s ability to change the aircraft’s
center of gravity with respect to the wing. Flight control of
the aircraft depends on the wing’s ability to flexibly deform
rather than the use of control surfaces.
Whip stall. A pitch attitude that is too high for a WSC,
at which the tips would stall from flying outside the WSC
limitations or flying in extreme/severe turbulence.
Wind correction angle. Correction applied to the course to
establish a heading so that track will coincide with course.
Also called the Crab angle.
Wind direction indicators. Indicators that include a
wind sock, wind tee, or tetrahedron. Visual reference will
determine wind direction and runway in use.
Wind drift correction. Correction applied to the heading
of the aircraft necessary to keep the aircraft tracking over a
desired track. Also called the wind correction angle or crab
angle.
Wind shear. A sudden, drastic shift in wind speed, direction,
or both that may occur in the horizontal or vertical plane.
Wing. A fabric skin with an aluminum frame that produces
the lift necessary to support the WSC in flight; including the
flight wires/control frame below and the ground wires/king
post above.
Wing keel. The WSC structural component in the longitudinal
center of the wing that connects the two leading edges
together at the nose and connects the carriage to the wing.
Wing loading. The amount of weight that a wing must
support to provide lift.
Wingspan. The maximum distance from wingtip to
wingtip.
Wing twist. A design feature of the WSC that reduces the
angle of attack from the root to the tip.
Wingtip vortices. The rapidly rotating air that spills over an
aircraft’s wings during flight. The intensity of the turbulence
depends on the aircraft’s weight, speed, and configuration. It
is also referred to as wake turbulence. Vortices from heavy
aircraft may be extremely hazardous to small aircraft.
World Aeronautical Charts (WAC). A standard series
of aeronautical charts covering land areas of the world at a
size and scale convenient for navigation (1:1,000,000) by
moderate speed aircraft. Topographic information includes
cities and towns, principal roads, railroads, distinctive
landmarks, drainage, and relief. Aeronautical information
includes visual and radio aids to navigation, airports, airways,
restricted areas, obstructions and other pertinent data.
WSC. See weight-shift control.
Weight-Shift Control—Land (WSCL). WSC that takes off
and lands on land. This can be wheels or ski equipped.
Weight-Shift Control—Sea (WSCS). WSC that takes of the
water. This can be pontoons or a boat configuration.
Yaw. Rotation about the vertical axis of an aircraft.
Zulu time. A term used in aviation for Coordinated Universal
Time (UTC) which places the entire world on one time
standard.
Index
black-hole approach .....................................................12-8
bouncing during touchdown ......................................11-29
cables and hardware .......................................................3-7
camber ............................................................................2-1
carriage .........................................................................3-10
carriage inspection .......................................................5-18
carriage moments ............................................... 2-16, 2-17
center of gravity ...........................................................2-11
certifi cates and documents ...........................................5-15
checklist after entering fl ight deck ...............................5-23
checklist for taxi ...........................................................5-25
climbs and climbing turns ............................................6-12
collision avoidance .........................................................1-9
communications ...........................................................3-19
confi ned areas ...............................................................13-7
control frame ..................................................................3-4
controlled airports ........................................................10-2
controlled airspace .........................................................8-4
controlled fi ring areas ..................................................8-10
cooling systems ............................................................5-20
coordinating the controls ................................................6-8
crosswind approaches and landings ...........................11-17
landings ..................................................................11-19
leg .............................................................................10-2
takeoff .........................................................................7-6
crosswind pattern procedures .....................................11-17
dashboards and instrument panels ...............................3-16
deck angle ......................................................................2-4
departure leg .................................................................10-2
descents and descending turns .....................................6-14
descent at minimum safe airspeed ...............................6-14
ditching ........................................................................13-8
downwind leg ...............................................................10-2
drag ........................................................................ 2-7, 2-8
drift and ground track control ........................................9-2
dynamic pressure ...........................................................2-7
abnormal engine instrument indications ....................13-13
aeronautical decision-making ............................ 1-10, 13-1
after landing .................................................................5-26
after landing roll ...........................................................11-7
airfoil ..............................................................................2-1
airport and navigation lighting aids .............................12-4
airport operations .........................................................10-2
airspace ..........................................................................8-2
Class A Airspace ........................................................8-8
Class B Airspace ........................................................8-7
Class C Airspace ........................................................8-6
Class D Airspace ........................................................8-6
Class E Airspace .........................................................8-4
Class G Airspace ........................................................8-2
alert areas .....................................................................8-10
alternating turns .........................................................11-21
angle of attack ................................................................2-4
approach .......................................................................13-6
approaches and landings ............................................12-11
AROW .........................................................................5-15
aspect ratio .....................................................................2-5
attitude and sink rate control ........................................13-5
attitude control ...........................................................13-18
attitude fl ying .................................................................6-4
avoiding pilot errors .....................................................1-11
axes of rotation .............................................................2-12
ballistic parachute system .................................. 3-15, 13-2
ballooning during roundout ........................................11-29
bank control ...................................................................6-4
base leg ............................................................... 10-2, 11-2
basic pilot eligibility ......................................................1-9
basic propeller principles .............................................2-20
basic safety concepts ....................................................13-4
battens and leading edge stiffener ..................................3-7
before takeoff check .....................................................5-26
best angle of climb speed .............................................6-13
best rate of climb speed ................................................6-12
effects and hazards of high crosswinds for
approaches and landings ............................................11-17
effects and the use of the controls ..................................6-2
effect of headwinds during fi nal approach ...................11-8
electrical fi res .............................................................13-12
electrical system ............................................... 3-15, 13-12
emergency approaches and landings ..........................11-26
descents ..................................................................13-10
equipment and survival gear ....................................13-8
landings ....................................................................13-3
energy management .....................................................6-19
engine and gearbox ......................................................3-20
engine failure after takeoff ...........................................13-9
engine fi re ...................................................................13-10
engine instruments .......................................................3-17
engine start ...................................................................5-23
entering a turn ................................................................6-8
equipment and lighting ................................................12-2
estimating height and movement .................................11-5
exiting a turn ..................................................................6-8
fatigue ..........................................................................1-13
faulty approaches and landings ..................................11-27
feel of the aircraft ...........................................................6-3
fi nal approach ..................................................... 10-2, 11-4
fl are ..............................................................................11-6
fl ex wing.........................................................................2-6
fl ight deck .....................................................................3-16
inspection .................................................................5-20
fl ight deck management ...........................................5-23
fl ight instruments .........................................................3-17
fl ight operations and pilot certifi cates ............................1-8
fl ight over charted u.s. wildlife refuges, parks, and
forest service areas .......................................................8-12
fl oating during roundout ............................................11-28
forced landing ..............................................................13-3
forces in fl ight ................................................................2-7
fuel ...............................................................................5-20
fuel system components ...............................................3-20
glide ..............................................................................6-14
fl ight ...........................................................................2-6
turns ..........................................................................6-16
go-around ...................................................................11-13
ground adjustable trim systems ......................................3-9
ground effect ................................................................2-11
on takeoff ....................................................................7-7
ground roll ......................................................................7-2
hang glider .....................................................................1-4
hard landing ...............................................................11-30
high angles of attack ....................................................2-13
high fi nal approach .....................................................11-27
high roundout .............................................................11-28
high winds and strong turbulence ..............................13-15
during cruise fl ight .................................................13-15
during takeoffs and landings ..................................13-15
high winds during taxi ...............................................13-15
hypothermia .................................................................1-13
inadvertant propeller strike ........................................13-13
inadvertent fl ight into instrument meteorological
conditions ...................................................................13-16
induced drag ...................................................................2-8
infl ight adjustable trim systems ...................................3-10
infl ight fi re ..................................................................13-10
initial climb ..................................................... 7-2, 7-4, 7-6
instrument panel arrangements ....................................3-17
keel .................................................................................3-3
kinesthesia ......................................................................6-4
king post with wires-on-top wing design .......................3-5
landing gear ..................................................................3-11
for water and snow ...................................................3-14
malfunction .............................................................13-13
lateral axis ....................................................................2-12
pitch ..........................................................................2-12
late or rapid roundout .................................................11-28
leading edges ..................................................................3-2
level turns .......................................................................6-7
lift ...................................................................................2-7
lift-off ..................................................................... 7-2, 7-3
and climb out ..............................................................7-9
and initial climb ........................................................7-12
light sport aircraft ...........................................................1-6
Lilienthal, Otto ...............................................................1-2
local airport advisory ...................................................8-11
local conditions ..............................................................5-3
longitudinal axis ................................................... 2-3, 2-13
low angles of attack .....................................................2-14
low fi nal approach ......................................................11-27
maintaining aircraft control ........................................13-17
maneuvering by reference to ground objects .................9-2
maximum crosswind velocities ..................................11-19
medical factors .............................................................1-13
medium turns .................................................................6-8
military operations areas ................................................8-9
military training routes .................................................8-11
motorized hang gliders ...................................................1-4
national security areas ..................................................8-12
navigating the airspace .................................................8-13
navigation instruments .................................................3-17
night fl ying ...................................................................12-9
emergencies ............................................................12-12
illusions ....................................................................12-7
takeoff .......................................................................12-9
vision ........................................................................12-5
noise abatement ............................................................7-13
normal (calm wind) approaches and landings .............11-2
normal climb ................................................................6-12
normal takeoff ................................................................7-2
occupant prefl ight brief ................................................5-22
oil .................................................................................5-21
orientation and navigation ..........................................12-10
other airspace areas ......................................................8-11
parachute jump areas ....................................................8-11
parasite drag ...................................................................2-8
partial power descent ...................................................6-14
PAVE .............................................................................5-1
pilot equipment ............................................................12-3
pilot requirements ........................................................12-2
pitch ..............................................................................2-12
and power .................................................................6-16
angle ...........................................................................2-4
control .........................................................................6-4
control system ............................................................3-8
moments summary ...................................................2-16
pressures ...................................................................2-14
pitot-static system ......................................................13-12
planform .........................................................................2-5
pockets and hardware .....................................................3-7
porpoising ..................................................................11-29
positive transfer of controls .........................................1-10
postfl ight, parking, and securing ..................................5-27
power ..........................................................................11-13
power-off accuracy approaches .................................11-21
180° ........................................................................11-23
360° ........................................................................11-25
90° ..........................................................................11-22
power-off stall manuever .............................................6-23
powerplant inspection ..................................................5-19
powerplant system .......................................................3-19
power control .................................................................6-4
precautionary landing ...................................................13-3
prefl ight actions ..............................................................5-3
prefl ight inspection .......................................................5-15
preparation and prefl ight ..............................................12-8
prohibited areas ..............................................................8-8
psychological hazards ..................................................13-3
published VFR routes ..................................................8-12
ready aircraft to enter fl ight deck .................................5-22
recognition .................................................................13-17
rectangular course ..........................................................9-4
refl ex systems .................................................................3-8
regional weather .............................................................5-3
rejected landings ........................................................11-13
rejected takeoff/engine failure .....................................7-12
resource management ...................................................1-12
restricted areas ...............................................................8-9
Rogallo, Francis .............................................................1-2
roll ................................................................................2-13
control system ............................................................3-9
stability and moments ...............................................2-16
rotation ...........................................................................7-2
rotation and lift-off .........................................................7-6
roundout .......................................................................11-6
routine prefl ight inspection ..........................................5-16
runaway throttle .........................................................13-13
runup ............................................................................12-8
runway incursion avoidance ........................................1-10
s-turns across a road .......................................................9-7
sail components ..............................................................3-6
attachment to wing frame ...........................................3-7
material and panels .....................................................3-7
scenario-based training ................................................1-12
setting up the WSC aircraft ............................................5-8
shallow turns ..................................................................6-8
short-fi eld approaches and landings ...........................11-14
short fi eld takeoff and steepest angle climb ...................7-8
simulated engine out ..................................................11-26
slow fi nal approach ....................................................11-27
slow fl ight ....................................................................6-20
and stalls ...................................................................6-20
soft and rough fi eld takeoff and climb .........................7-10
approaches and landings .........................................11-15
special use airspace ........................................................8-8
speed ..........................................................................11-13
stability and moments ..................................................2-13
stabilized approach concept .......................................11-10
stalls .............................................................................6-21
exceeding the critical AOA ......................................2-18
standard airport traffi c patterns ....................................10-2
starting ..........................................................................12-8
steep angle ..................................................................11-21
steep approach .................................................. 6-14, 11-20
steep turns ......................................................................6-8
performance maneuver .............................................6-16
straight-and-level fl ying .................................................6-4
structure ........................................................................3-11
stuck throttle ...............................................................13-13
system malfunctions ...................................................13-12
takeoff and climb .........................................................12-9
takeoff roll ...................................... 7-2, 7-3, 7-6, 7-9, 7-12
taking down the wsc aircraft ........................................5-12
taxiing ................................................................ 5-24, 12-8
temporary fl ight restrictions .........................................8-11
terminal radar service areas .........................................8-12
terrain selection ............................................................13-6
terrain types ..................................................................13-7
the propeller .................................................................3-20
throttle use ....................................................................11-2
thrust .................................................................... 2-7, 2-10
thrust moments .............................................................2-18
thrust required for increases in speed ...........................2-11
topless wings with struts ................................................3-5
touchdown ....................................................................11-7
towered airport operations .............................................8-6
transporting ....................................................................5-7
trim—normal stabilized fl ight ......................................2-13
control .........................................................................6-7
systems .......................................................................3-9
tuning the wing to fl y slower or faster .........................5-14
tuning the wing to fl y straight ......................................5-14
turbulent air approaches and landings ........................11-16
turns............................................................................13-18
around a point .............................................................9-9
uncontrolled airports ....................................................10-2
uncontrolled airspace .....................................................8-2
unique airfoil and wing design .....................................2-13
unique WSC fl ight characteristics ................................12-7
upwind leg ....................................................................10-2
use of checklists ...........................................................1-12
use of power ...............................................................11-28
vertical axis ..................................................................2-13
warning areas .................................................................8-9
water landings ..............................................................13-8
weather ...........................................................................5-3
weather related emergencies ......................................13-15
weight ................................................................... 2-7, 2-10
weight and loading .........................................................5-5
weight, load, and speed ................................................2-20
weight-shift control aircraft ...........................................1-7
weight-shift control LSA requirements .........................1-8
whip stall–tuck–tumble ................................................2-19
awareness .................................................................6-24
wing................................................................................3-2
chord ...........................................................................2-2
fl exibility ....................................................................2-6
frame components ......................................................3-2
inspection .................................................................5-17
loading ........................................................................2-6
rising after touchdown ............................................11-30
systems .......................................................................3-8
tuning ........................................................................5-14
twist ............................................................................2-3
Wright Flyer ...................................................................1-2
WSC and air traffi c control ..........................................8-12
WSC operations ...........................................................8-12
yaw ...............................................................................2-13
stability and moments ...............................................2-17
stability summary .....................................................2-18