Glossary

Velocity. The speed or rate of movement in a certain V-G diagram. A chart that relates velocity to load factor. It direction. is valid only for a specific weight, configuration and altitude and shows the maximum amount of positive or negative lift Venturi tube. A specially shaped tube attached to the outside the airplane is capable of generating at a given speed. Also of an aircraft to produce suction to allow proper operation shows the safe load factor limits and the load factor that the of gyro instruments. aircraft can sustain at various speeds. Vertical axis. An imaginary line passing vertically through Victor airways. Airways based on a centerline that extends the center of gravity of an aircraft. The vertical axis is called from one VOR or VORTAC navigation aid or intersection, the z-axis or the yaw axis. to another navigation aid (or through several navigation aids or intersections); used to establish a known route for en route Vertical card compass. A magnetic compass that consists of procedures between terminal areas. an azimuth on a vertical card, resembling a heading indicator with a fixed miniature airplane to accurately present the Visual approach slope indicator (VASI). A visual aid of heading of the aircraft. The design uses eddy current damping lights arranged to provide descent guidance information to minimize lead and lag during turns. during the approach to the runway. A pilot on the correct glideslope will see red lights over white lights. Vertical speed indicator (VSI). A rate-of-pressure change instrument that gives an indication of any deviation from a Visual descent point (VDP). A defined point on the final constant pressure level. approach course of a nonprecision straight-in approach procedure from which normal descent from the MDA to the Vertical stability. Stability about an aircraft’s vertical axis. runway touchdown point may be commenced, provided the Also called yawing or directional stability. runway environment is clearly visible to the pilot. Very-high frequency (VHF). A band of radio frequencies Visual flight rules (VFR). Flight rules adopted by the falling between 30 and 300 MHz. FAA governing aircraft flight using visual references. VFR operations specify the amount of ceiling and the visibility the Very-high frequency omnidirectional range (VOR). pilot must have in order to operate according to these rules. Electronic navigation equipment in which the flight deck When the weather conditions are such that the pilot cannot instrument identifies the radial or line from the VOR station, operate according to VFR, he or she must use instrument measured in degrees clockwise from magnetic north, along flight rules (IFR). which the aircraft is located. Visual meteorological conditions (VMC). Meteorological Vestibule. The central cavity of the bony labyrinth of the conditions expressed in terms of visibility, distance from ear, or the parts of the membranous labyrinth that it contains. cloud, and ceiling meeting or exceeding the minimums specified for VFR. V . The maximum speed with the flaps extended. The upper FE limit of the white arc. V . Landing gear extended speed. The maximum speed at LE which an airplane can be safely flown with the landing gear VFR. See visual flight rules. extended. VFR on top. ATC authorization for an IFR aircraft to operate V .Landing gear operating speed. The maximum speed for LO in VFR conditions at any appropriate VFR altitude. extending or retracting the landing gear if using an airplane equipped with retractable landing gear. VFR over the top. A VFR operation in which an aircraft operates in VFR conditions on top of an undercast. V . Minimum control airspeed. This is the minimum MC flight speed at which a light, twin-engine airplane can be VFR terminal area chart. At a scale of 1:250,000, a chart satisfactorily controlled when an engine suddenly becomes that depicts Class B airspace, which provides for the control inoperative and the remaining engine is at takeoff power. or segregation of all the aircraft within the Class B airspace. The chart depicts topographic information and aeronautical VMC. See visual meteorological conditions. information including visual and radio aids to navigation, airports, controlled airspace, restricted areas, obstructions, and related data. G-33