An instrument used with some of the larger reciprocating engines and turboprop or turboshaft engines to measure the reaction between the propeller reduction gears and the engine case.

The sum of the parasite drag and induced drag.

The control of IFR en route traffic within delegated airspace between two or more adjacent approach control facilities, designed to expedite traffic and reduce control and pilot communication requirements.

See United States Terminal Procedures Publication.

The actual path made over the ground in flight.

Flying a heading that will maintain the desired track to or from the station regardless of crosswind conditions.

An airborne system developed by the FAA that operates independently from the ground-based Air Traffic Control system. Designed to increase flight deck awareness of proximate aircraft and to serve as a “last line of defense” for the prevention of midair collisions.

A ground-based service providing information to the flight deck via data link using the S-mode transponder and altitude encoder to improve the safety and efficiency of “see and avoid” flight through an automatic display that informs the pilot of nearby traffic.

The portion of the airfoil where the airflow over the upper surface rejoins the lower surface airflow.

Meteorological and aeronautical data recorded on tapes and broadcast over selected NAVAIDs. Generally, the broadcast contains route-oriented data with specially prepared NWS forecasts, inflight advisories, and winds aloft. It also includes selected current information such as weather reports (METAR/SPECI), NOTAMs, and special notices.

The airborne portion of the ATC radar beacon system.

One of 4,096 four-digit discrete codes ATC assigns to distinguish between aircraft.

Immediate indication of the direction of aircraft movement, as shown on instruments.

Landing gear employing a third wheel located on the nose of the aircraft.

To adjust the aerodynamic forces on the control surfaces so that the aircraft maintains the set attitude without any control input.

A small auxiliary hinged portion of a movable control surface that can be adjusted during flight to a position resulting in a balance of control forces.

. The boundary layer between the troposphere and the mesosphere which acts as a lid to confine most of the water vapor, and the associated weather, to the troposphere.

The layer of the atmosphere extending from the surface to a height of 20,000 to 60,000 feet, depending on latitude.

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.

Per 14 CFR part 1: “A referenced airspeed obtained after lift-off at which the required one-engine-inoperative climb performance can be achieved.”

See terrain awareness and warning system.

Omnidirectional lights that outline the edges of the taxiway and are blue in color.

Lights that are flush with the runway which emit a steady green color.

See traffic alert collision avoidance system.

See Tower En Route Control.

The manner in which procedures are executed.

Telephone recording of area and/or route meteorological briefings, airspace procedures, and special aviation-oriented announcements.

Restriction to flight imposed in order to: 1. Protect persons and property in the air or on the surface from an existing or imminent flight associated hazard;2. Provide a safe environment for the operation of disaster relief aircraft; 3. Prevent an unsafe congestion of sightseeing aircraft above an incident; 4. Protect the President, Vice President, or other public figures; and, 5. Provide a safe environment for space agency operations. Pilots are expected to check appropriate NOTAMs during flight planning when conducting flight in an area where a temporary flight restriction is in effect.

Maintaining an excessively strong grip on the control column, usually resulting in an overcontrolled situation.

A report established for the 5 statute mile radius around an airport. Utilizes the same descriptors and abbreviations as the METAR report.

Areas where participating pilots can receive additional radar services. The purpose of the service is to provide separation between all IFR operations and participating VFR aircraft.

A timed-based system that provides information concerning potential hazards with fixed objects by using GPS positioning and a database of terrain and obstructions to provide true predictability of the upcoming terrain and obstacles.

See temporary flight restriction.

The last layer of the atmosphere that begins above the mesosphere and gradually fades away into space.

The force which imparts a change in the velocity of a mass. This force is measured in pounds but has no element of time or rate. The term “thrust required” is generally associated with jet engines. A forward force which propels the airplane through the air.

The forward aerodynamic force produced by a propeller, fan, or turbojet engine as it forces a mass of air to the rear, behind the aircraft.

An imaginary line passing through the center of the propeller hub, perpendicular to the plane of the propeller rotation.

See traffic information service.

The aerodynamic pitching moments required to return the aircraft to the equilibrium angle of attack.

Pressure of air that is still or not moving, measured perpendicular to the surface of the aircraft.

The initial tendency an aircraft displays when disturbed from a state of equilibrium.

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.

A front that is moving at a speed of less than 5 knots.

In instrument flight, any turn greater than standard rate; in visual flight, anything greater than a 45° bank.

A layer of the atmosphere above the tropopause extending to a height of approximately 160,000 feet.

The body’s response to demands placed upon it.

The personal analysis of the kinds of stress experienced while flying, the application of appropriate stress assessment tools, and other coping mechanisms.

The accumulation of ice on the exterior of the aircraft.

Process by which a solid is changed to a gas without going through the liquid state.

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.

An engine- or exhaust-driven air compressor used to provide additional pressure to the induction air so the engine can produce additional power.

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

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.

A device used to transmit indications of angular movement or position from one location to another.

A realistic display depiction of the aircraft in relation to terrain and flight path.

See tactical air navigation.

An electronic navigation system used by military aircraft, providing both distance and direction information.

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.”

The misperception of being in a nose-up or nose-down attitude, caused by a rapid acceleration or deceleration while in flight situations that lack visual reference.

The state of confusion due to misleading information being sent to the brain from various sensory organs, resulting in a lack of awareness of the aircraft position in relation to a specific reference point.

A flight permit issued to an aircraft that does not meet airworthiness requirements but is capable of safe flight. A special flight permit can be issued to move an aircraft for the purposes of maintenance or repair, buyer delivery, manufacturer flight tests, evacuation from danger, or customer demonstration. Also referred to as a ferry permit.

Airspace in which flight activities are subject to restrictions that can create limitations on the mixed use of airspace. Consists of prohibited, restricted, warning, military operations, and alert areas.

The distance traveled in a given time.

An aggravated stall that results in an airplane descending in a helical, or corkscrew path.

A condition that exists when the static directional stability of the airplane is very strong as compared to the effect of its dihedral in maintaining lateral equilibrium.

The slipstream of a propeller-driven airplane rotates around the airplane. This slipstream strikes the left side of the vertical fin, causing the aircraft to yaw slightly. Rudder offset is sometimes used by aircraft designers to counteract this tendency.

High-drag devices that can be raised into the air flowing over an airfoil, reducing lift and increasing drag. Spoilers are used for roll control on some aircraft. Deploying spoilers on both wings at the same time allows the aircraft to descend without gaining speed. Spoilers are also used to shorten the ground roll after landing.

See single-pilot resource management.

See secondary surveillance radar.

See standard service volume.

A single-piece horizontal tail surface on an airplane that pivots around a central hinge point. A stabilator serves the purposes of both the horizontal stabilizer and the elevators.

The inherent quality of an airplane to correct for conditions that may disturb its equilibrium, and to return or to continue on the original flightpath. It is primarily an airplane design characteristic.

A type of hypoxia that results when the oxygen-rich blood in the lungs is not moving to the tissues that need it.

A rapid decrease in lift caused by the separation of airflow from the wing’s surface, brought on by exceeding the critical angle of attack. A stall can occur at any pitch attitude or airspeed.

At sea level, the standard atmosphere consists of a barometric pressure of 29.92 inches of mercury (“Hg) or 1013.2 millibars, and a temperature of 15 °C (59 °F). Pressure and temperature normally decrease as altitude increases. The standard lapse rate in the lower atmosphere for each 1,000 feet of altitude is approximately 1 “Hg and 2 °C (3.5 °F). For example, the standard pressure and temperature at 3,000 feet mean sea level (MSL) are 26.92 “Hg (29.92 “Hg – 3 “Hg) and 9 °C (15 °C – 6 °C).

This weight consists of the airframe, engines, and all items of operating equipment that have fixed locations and are permanently installed in the airplane including fixed ballast, hydraulic fluid, unusable fuel, and full engine oil.

Defines the limits of the volume of airspace which the VOR serves.

Weights established for numerous items involved in weight and balance computations. These weights should not be used if actual weights are available.

A satellite technology permitting the Department of Defense (DOD) to create, in the interest of national security, a significant clock and ephemeris error in the satellites, resulting in a navigation error.

An inner ear organ that detects angular acceleration of the body.

A fuselage design that includes a substructure of bulkheads and/or formers, along with stringers, to support flight loads and stresses imposed on the fuselage.

A form of multipointer pneumatic altimeter with an adjustable barometric scale that allows the reference pressure to be set to any desired level.

The maximum density altitude where the best rate-of-climb airspeed will produce a 100-feet-per-minute climb at maximum weight while in a clean configuration with maximum continuous power.

A motor or other form of actuator which receives a small signal from the control device and exerts a large force to accomplish the desired work.

An auxiliary control mounted on a primary control surface, which automatically moves in the direction opposite the primary control to provide an aerodynamic assist in the movement of the control.

The acronym for Significant Meteorological information. A weather advisory issued concerning weather significant to the safety of all aircraft.

An indication of signal strength received compared to background noise, which is a measure of the adequacy of the received signal.

Presents four panels showing forecast significant weather.

Transmission and reception on the same frequency.

The ability for a pilot to manage all resources effectively to ensure the outcome of the flight is successful.

Pilot knowledge of where the aircraft is in regard to location, air traffic control, weather, regulations, aircraft status, and other factors that may affect flight.

An uncoordinated turn in which the rate of turn is too great for the angle of bank, pulling the aircraft to the outside of the turn.

The procedural, psychomotor, and perceptual skills used to control a specific aircraft or its systems. They are the airmanship abilities that are gained through conventional training, are perfected, and become almost automatic through experience.

Drag generated between air molecules and the solid surface of the aircraft.

The horizontal distance from the aircraft antenna to the ground station, due to line-of-sight transmission of the DME signal.

A system whereby the heading gyro is “slaved to,” or continuously corrected to bring its direction readings into agreement with a remotely located magnetic direction sensing device (usually a flux valve or flux gate compass).

An uncoordinated turn in which the aircraft is banked too much for the rate of turn, so the horizontal lift component is greater than the centrifugal force, pulling the aircraft toward the inside of the turn.

An airplane of 12,500 pounds or less maximum certificated takeoff weight.

The future impact of a hazard that is not eliminated or controlled.