Recovery phase.........................................................8-17 Spiral dives...................................................................8-15 Spoiler/dive brake malfunctions ..................................8-24 Spoilers ..........................................................................2-5 Stabilator ........................................................................2-6 Stability ........................................................................3-10 Dihedral ....................................................................3-12 Dynamic stability .....................................................3-10 Flutter  .......................................................................3-11 Lateral stability.........................................................3-12 Static stability ...........................................................3-10 Stall recognition and recovery .....................................7-32 Stalls.............................................................................3-17 Stall speed ......................................................................5-6 Standard atmosphere......................................................9-3 Static pressure lines........................................................4-2 Stowage........................................................................8-30 Straight glides ..............................................................7-27 Strop...............................................................................1-6 Survival gear checklists ...............................................8-28 Sustainer engines ...........................................................2-8 Swept-forward wing.......................................................3-7 System and equipment malfunctions ...........................8-20 Tailwheel/tailskid equipped glider oscillations  during launches and landings  .........................................8-8 Tailwind  .........................................................................5-3 Takeoff  .........................................................................12-7 Takeoff emergencies  ..................................................12-11 Glider climbs excessively high during takeoff.......12-11 Glider releases during takeoff with tow plane  operation normal .....................................................12-11 Tow plane power failure on the runway during  takeoff roll  ..............................................................12-11 Tow plane power failure or tow rope break after  takeoff above 200 feet ............................................12-11 Tow plane power failure or tow rope break after  takeoff but below 200 feet above ground level ......12-11 Take off planning  .........................................................12-5 Takeoff procedures and techniques ...............................7-3 Taxiing  .........................................................................7-18 Temperature  ........................................................... 5-3, 9-2 Thermal  ..........................................................................9-6 Thermal characteristics theories  ..................................10-2 Thermal indicators  .......................................................10-3 Thermal shape and structure  ..........................................9-6 Thermal soaring weather  ................................................9-6 Thermal waves ...............................................................9-9 Thrust  .............................................................................3-9 Variometer  ...................................................................4-11 Audio variometers ....................................................4-13 Electric variometers..................................................4-11 Unassisted takeoff  ..........................................................7-5 Using the plotter  ...........................................................11-5 Thunderstorms  .............................................................9-10 Cumulus stage ..........................................................9-11 Dissipating stage ......................................................9-12 Mature stage .............................................................9-11 Tiedown  .........................................................................6-4 Tips and techniques....................................................10-15 Total energy system  .....................................................4-14 Tow failure  ........................................................... 7-9, 8-10 Above 800' AGL ......................................................8-12 Above return to runway alititude..............................8-11 Above traffic pattern altitude....................................8-13 Without runway to land below returning altitude ....8-11 With runway to land and stop...................................8-11 Tow hook  .....................................................................12-2 Schweizer tow hook .................................................12-2 Tost tow hook  ...........................................................12-2 Towhook devices ...........................................................2-7 Towhook malfunctions  ................................................8-25 Towhook system failures  ...............................................8-8 Tow ring inspection  .....................................................12-4 Tow rope inspection  .....................................................12-4 Tow rope strength requirements...............................12-4 Tow speeds  ...................................................................7-12 Trailering  ........................................................................6-3 Transponder code  .........................................................13-9 Traps  ..........................................................................10-10 Trim ballast  ..................................................................5-14 Trim devices...................................................................2-6 True airspeed  ..............................................................10-17 True altitude  .................................................................4-10 Turn coordination  .........................................................3-15 Turns  ............................................................................7-28 Medium turns ...........................................................7-28 Shallow turns............................................................7-28 Steep turns ................................................................7-31 Turns on tow  .............................................................12-9 Types of airspeed  ...........................................................4-3 Calibrated airspeed ....................................................4-3 Indicated airspeed ......................................................4-3 True airspeed .............................................................4-4 Types of altitude  ..........................................................4-10 Types of drag   ................................................................3-3 T U V I-5