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. 

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. 

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. 

Strapdown system. An INS in which the accelerometers and gyros are permanently “strapped down” or aligned with the three axes of the aircraft. 

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. 

Structural icing. The accumulation of ice on the exterior of the aircraft. 

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. 

Supercooled water droplets.  Water droplets that have been cooled below the freezing point, but are still in a liquid state. 

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. 

## T 

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. 

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.” 

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. 

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. 

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. 

