- Airspeed: The speed of the airplane relative to the air. Expressed in several ways indicated airspeed, calibrated airspeed, equivalent airspeed, and true airspeed. It is measured with an airspeed indicator.
- Angle of Attack: The angle between where the wing is pointing and where it is going. (The amount of lift generated by a wing is directly related to the angle of attack, with greater angles generating more lift, as well as more drag. This remains true up to the stall point, where lift starts to decrease again because of flow separation.)
- Bench Test: The testing of an airplane component, typically in a laboratory simulated environment.
- EME: Electromagnetic energy – lightning is one source.
- EMI: Electromagnetic interference – from lightning or other electrical sources.
- Empennage: Tail Section including the vertical fin, horizontal stabilizer, elevator and rudder.
- Extended Operations (ETOPS): Rule allowing operators of approved jetliners to fly routes that take the airplane beyond the standard allowable flying time of an alternate airport. Under ETOPS twin-engine commercial airplanes are permitted to fly routes that take them beyond 60 minutes of an alternate airport and allows three- and four-engine passenger jetliners to fly air routes that take them beyond 180 minutes of an alternate airport.
- Federal Aviation Administration (FAA): Responsible for the safety of civil aviation in the United States. The Federal Aviation Act of 1958 created the agency under the name Federal Aviation Agency. The present name was adopted in 1967 when the FAA became a part of the Department of Transportation.
- Federal Aviation Regulations (FARs): In the U.S., the legal requirements and rules for the aviation industry.
- Flight Squawk: An entry on the flight discrepancy form describing an anomalous condition noted during flight.
- Fuselage: The body of the airplane.
- Go Around: A go-around is an aborted landing of an airplane that is on final approach.
- Instrument Flight Rules (IFR): Rules allowing aircraft to fly in areas of reduced visibility such as through clouds and fog with the use of the airplane’s flight deck instruments.
- Instrument Landing System (ILS): A ground-based system that provides landing approach guidance to airplanes and can be used at times of low visibility to aid in landing.
- Line Replaceable Unit (LRU): A self-contained, easily removable airplane component.
- Mach: Speed measurement based on the speed of sound.
- Master Minimum Equipment List (MMEL): An airplane-specific list of equipment that is allowed to be inoperative and still allow for dispatch of the flight.
- Maximum Takeoff Weight (MTOW): The maximum weight at which the pilot of an airplane is allowed to attempt takeoff. The MTOW of an aircraft is fixed. It does not vary with altitude or air temperature or the length of the runway to be used for takeoff or landing.
- Nacelle: The cowling surrounding the engine.
- Non-Destructive Inspection (NDI): Inspection of parts and materials methods that do not affect the physical characteristics or function of a part, component, structure or tooling.
- Rejected Takeoff: An aborted takeoff.
- Stall Test: In-flight testing wherein the Angle of Attack is raised to the point that the wings are no longer producing lift to understand the aerodynamic characteristics.
- Tailstrike: An extreme takeoff condition in which the tail strikes the surface of the runway.
- Touch and Go: Maneuver consisting of touching wheels down on runway and then taking off again.
- Type Inspection Authorization(TIA): A document that starts the formal FAA flight test certification program.
- Visual Flight Rules (VFR): Rules governing flight in day and night visual flight conditions.
- Vmc: The airspeed at which, when an engine is made inoperative, it is possible to recover the airplane and maintain straight flight (with a maximum 50 favorable bank angle) even with the most unfavorable flap setting and takeoff thrust on the operating engine.