standard day conditions. Conditions that have been decided upon by the ICAO (International Civil Aeronautics Organization) for relating all aircraft and engine performance to a given reference. See standard atmospheric conditions.
standard-frequency signal (radio-frequency signal standard). A highly accurate radio-frequency signal broadcast from the National Bureau of Standards radio station, station WWV. The standard-frequency signal is broadcast on frequencies of 2.5, 5.0, 10.0, 15.0, 20.0, and 25.0 megahertz.
standard-rate turn (aircraft flight maneuver). A turn in which an aircraft changes its direction at a rate of 3° per second (360° in two minutes) for low-or medium-speed aircraft. For high-speed aircraft, the standard-rate turn is 1 1/2° per second (360° in four minutes).
standard terminal arrival. See STAR.
standard weights (aircraft operations). Values used when specific weights are not available:
Gasoline 6.0 pounds/U.S. gallon
Turbine engine fuel 6.7 pounds/U.S. gallon
Lubricating oil 7.5 pounds/U.S. gallon
Water 8.35 pounds/U.S. gallon
Aircraft load
General aviation
Crew & passengers 170 pounds Air carrier
Passenger (summer) 160 pounds
Passenger (winter) 165 pounds
Male cabin attendant 150 pounds
Female cabin attendant 130 pounds
Other crewmembers 170 pounds
Checked baggage 23.5 pounds
Carry-on baggage 5 pounds
standing wave (meteorology). A wave in the atmosphere that remains stationary in a moving fluid. The standing waves most commonly encountered in flight are mountain waves, or lee waves.
standing waves (electrical transmission line). Stationary voltage waves existing on an antenna or transmission line that are caused by two waves, identical in amplitude and frequency, but traveling in opposite directions along the conductor.
“Stand by” (air traffic control). A phrase used by ATC meaning that the controller or pilot must pause for a few seconds, usually to attend to other duties of a higher priority. It also means to wait, as in “stand by for clearance.” The phrase “stand by” is neither an approval nor denial.
standpipe. A pipe protruding upward from the bottom of a tank, or reservoir, that allows part of the tank to be used as a reserve, or standby, source of fluid. The oil supply tanks for some aircraft engines have a standpipe in them. The main engine-driven oil pump is supplied from the standpipe, and emergency oil to feather the propeller is taken from the bottom of the tank. If an oil leak causes a loss of all of the oil the engine pump can move, there is still enough oil left in the tank to feather the propeller.
staple (fastener). A U-shaped wire loop with sharp points on both ends. Staples are used to fasten wires to a wooden post or wall, and to fasten sheets of paper together.
staple (textile material). The average length of the fibers of a textile material. Cotton, for example, is classified as either long staple or short staple, depending upon the length of the cotton fibers.
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