W U V  I-8 Vacuum systems ........................................................10-48 Twin-engine aircraft vacuum system operation .....10-51 Typical pump-driven system ..................................10-50 Venturi tube systems ..............................................10-48 Vacuum tubes...............................................................11-4 Valves ............................................................ 12-22, 16-20 Flow control valves ................................................12-22 Check valve ........................................................12-25 Hydraulic fuses ...................................................12-27 Orifice-type check valve.....................................12-25 Pressure-controlled sequence valve ....................12-25 Selector valves ....................................................12-22 Sequence valves..................................................12-25 Pressure control valves...........................................12-27 Pressure reducers ................................................12-29 Pressure regulators..............................................12-29 Relief valves .......................................................12-28 Shuttle valves .........................................................12-30 Shutoff valves .....................................................12-30 Vapor cycle air conditioning servicing  equipment...................................................................16-52 Warnings and cautions...............................................10-75 Annunciator systems ..............................................10-75 Aural warning systems ...........................................10-77 Water..........................................................................17-10 Wheel construction Inboard wheel half..................................................13-36 Outboard wheel half ...............................................13-36 Wheel inspection........................................................13-37 Off aircraft wheel inspection..................................13-37 Balance weights ..................................................13-42 Cleaning the wheel assembly..............................13-38 Cleaning the wheel bearings...............................13-38 Disassembly of the wheel ...................................13-38 Fusible plug inspection .......................................13-42 Inspection of the wheel halves............................13-41 Key and key screw inspection ............................13-42 Wheel bearing inspection ...................................13-38 Bruising ...........................................................13-39 Flase brinelling ................................................13-39 Galling .............................................................13-38 Overheating .....................................................13-38 Staining and surface marks..............................13-40 Wheel tie bolt inspection ....................................13-42 On aircraft inspection .............................................13-37 Proper installation...................................................13-37 Axle nut torque ...................................................13-37 Wide area augmentation system (WAAS).................11-70 Windshield frost, fog, and ice control systems Chemical.................................................................15-32 Electric....................................................................15-30 Unijunction transistors (UJT) ....................................11-16 Tread.......................................................................13-78 Tire inspection on the aircraft ....................................13-79 Inflation ..................................................................13-79 Tread condition.......................................................13-81 Tread damage......................................................13-82 Tread depth and wear pattern .............................13-81 Tire mounting.............................................................13-89 Tubeless tires..........................................................13-90 Tube-type tires........................................................13-90 Tire removal...............................................................13-86 Tire repair and retreading...........................................13-87 Tire storage ................................................................13-88 Total air temperature measurement ...........................10-42 Transistors..................................................................11-11 Transmission lines .....................................................11-76 Triacs..........................................................................11-14 Triodes .........................................................................11-5 Troubleshooting the fuel system................................14-46 Fuel leak classification ...........................................14-46 Location of leaks and defects .................................14-46 Replacement of gaskets, seals, and packings .........14-47 Turbine engine fuels ....................................................14-8 Turbine engine fuel issues........................................14-9 Turbine engine fuel types .........................................14-8 Turbine fuel volatility...............................................14-8 Full service refrigerant recovery, recycling,  evacuation, and recharging units ............................16-53 Leak detectors.........................................................16-54 Manifold set, gauges, hoses, and fittings................16-52 Refrigerant source ..................................................16-54 Vacuum pumps.......................................................16-54 Vapor cycle air conditioning system components Compressor.............................................................16-49 Condenser...............................................................16-50 Evaporator ..............................................................16-48 Expansion valve .....................................................16-47 Receiver dryer ........................................................16-47 Refrigerant..............................................................16-46 Service valves.........................................................16-51 Vapor lock....................................................................14-4 Vertical magnetic compass ........................................10-45 Vibration isolation .....................................................11-73 Viscosity ......................................................................12-2 Volatility ......................................................................14-4