Supercooled water droplets.  Water droplets that have been  cooled below the freezing point, but are still in a liquid state.  STAR.  See standard terminal arrival route.  Static longitudinal stability.  The aerodynamic pitching  moments required to return the aircraft to the equilibrium  angle of attack.  Static pressure.  Pressure of air that is still or not moving,  measured perpendicular to the surface of the aircraft.  Surface analysis chart.  A report that depicts an analysis of  the current surface weather. Shows the areas of high and low  pressure, fronts, temperatures, dewpoints, wind directions  and speeds, local weather, and visual obstructions.  Synchro.  A device used to transmit indications of angular  movement or position from one location to another.  Synthetic vision.  A realistic display depiction of the aircraft  in relation to terrain and flight path.  Static stability.  The initial tendency an aircraft displays  when disturbed from a state of equilibrium.  Station.  A location in the airplane that is identified by a  number designating its distance in inches from the datum.  The datum is, therefore, identified as station zero. An item  located at station +50 would have an arm of 50 inches.  TAA.  See terminal arrival area.  TACAN.  See tactical air navigation.  Tactical air navigation (TACAN).  An electronic navigation  system used by military aircraft, providing both distance and  direction information.  Stationary front.  A front that is moving at a speed of less  than 5 knots.  Steep turns.  In instrument flight, any turn greater than standard  rate; in visual flight, anything greater than a 45° bank.  Stepdown fix.  The point after which additional descent is  permitted within a segment of an IAP.  Takeoff decision speed (V$_{1}$).  Per 14 CFR section 23.51:  “the calibrated airspeed on the ground at which, as a result  of engine failure or other reasons, the pilot assumed to have  made a decision to continue or discontinue the takeoff.”  Strapdown system.  An INS in which the accelerometers  and gyros are permanently “strapped down” or aligned with  the three axes of the aircraft.  Takeoff distance.  The distance required to complete an  all-engines operative takeoff to the 35-foot height. It must  be at least 15 percent less than the distance required for a  one-engine inoperative engine takeoff. This distance is not  normally a limiting factor as it is usually less than the one- engine inoperative takeoff distance.  Stratoshere.  A layer of the atmosphere above the tropopause  extending to a height of approximately 160,000 feet.  Stress.  The body’s response to demands placed upon it.  Stress management.  The personal analysis of the kinds of  stress experienced while flying, the application of appropriate  stress assessment tools, and other coping mechanisms.  Takeoff safety speed (V$_{2}$).  Per 14 CFR part 1: “A referenced  airspeed obtained after lift-off at which the required one­ engine-inoperative climb performance can be achieved.”  TAWS.  See terrain awareness and warning system.  Structural icing.  The accumulation of ice on the exterior  of the aircraft.  Taxiway lights.  Omnidirectional lights that outline the edges  of the taxiway and are blue in color.  Taxiway turnoff lights.  Lights that are flush with the runway  which emit a steady green color.  TCAS.  See traffic alert collision avoidance system.  TCH.  See threshold crossing height.  TDZE.  See touchdown zone elevation.  Sublimation.  Process by which a solid is changed to a gas  without going through the liquid state.  Suction relief valve.  A relief valve in an instrument vacuum  system required to maintain the correct low pressure inside  the instrument case for the proper operation of the gyros.  Supercharger.  An engine- or exhaust-driven air compressor  used to provide additional pressure to the induction air so the  engine can produce additional power.  G-29  T 