W  Y  Z  I-10  Zero fuel weight.........................................................10-10 Somatogravic illusion...............................................17-7 The leans...................................................................17-7 vestibular system..........................................................17-6 V$_{FE}$ ..............................................................................11-18 VFR terminal area charts .............................................16-2 VFR waypoints ..........................................................16-33 Vg diagram...................................................................5-37 Viscosity ........................................................................4-2 Visibility ....................................................................12-17 Vision in flight ...........................................................17-19 Visual approach slope indicator (VASI)....................14-16 visual flight rules (VFR) ..............................................16-1 Visual glide slope indicators......................................14-16 Visual illusions.............................................................17-8 Autokinesis...............................................................17-8 False horizon ............................................................17-8 V$_{LE}$..............................................................................11-18 V$_{LO}$..............................................................................11-18 V$_{NE}$..............................................................................11-19 V$_{NO }$.............................................................................11-19 VOR/DME RNAV.....................................................16-28 Vortex avoidance procedures.....................................14-28 Vortex behavior .........................................................14-27 Vortex generation.......................................................14-26 Vortex strength...........................................................14-27 V$_{S0 }$..............................................................................11-18 V$_{S1 }$..............................................................................11-18 V-Tail.............................................................................6-8 V$_{X}$ ...............................................................................11-18 V$_{Y}$ ...............................................................................11-18 Wake turbulence ................................................ 5-9, 14-26 Warning areas ..............................................................15-4 Water refraction .........................................................17-10 WCA ..........................................................................16-10 Weather ........................................................................12-1 Weather avoidance assistance....................................13-18 Weather briefings.........................................................13-5 Abbreviated briefing.................................................13-5 Outlook briefing .......................................................13-5 Standard briefing ......................................................13-5 Weather charts ...........................................................13-13 Significant weather prognostic charts ....................13-15 Surface analysis chart.............................................13-13 Dew point............................................................13-13 Present weather ..................................................13-13 Pressure change/tendency ..................................13-13 Sea level pressure ...............................................13-13 Sky cover .............................................................13-13 Temperature........................................................13-13 Yaw ..............................................................................5-13 Yawing.........................................................................5-19 Yaw String ...................................................................8-18 Wind....................................................................13-13 Weather depiction chart..........................................13-15 Weather check............................................................16-17 Weather products age and expiration.........................13-18 Weight.......................................... 5-1, 5-2, 5-8, 5-40, 10-2 Weight and balance............................................ 5-40, 10-4 Weight and balance computations............................10-5 Weight and balance restrictions ...............................10-6 Weight and loading distribution.....................................9-3 Weight control .............................................................10-1 Weight-shift-control.....................................................1-15 Wind correction angle (WCA)...................................16-16 Wind direction indicators...........................................14-20 Wind patterns ...............................................................12-7 Winds and temperature aloft forecast (FB)................13-13 Winds and temperatures aloft ......................................13-5 Wind shear Low-level wind shear .............................................12-11 Wind shifts .................................................................12-21 Wind sock ..................................................................14-20 Wind triangle .............................................................16-13 Winglets .........................................................................4-9 Wings .............................................................................3-3 Wingtip vortices.............................................................5-8 World aeronautical charts ............................................16-2 WSR-88D NEXRAD radar..........................................13-3