Aviation glossary: 32 flight terms in plain language

Terms

Angle of attack

Angle of attack is the angle between the wing and the oncoming air. A bigger angle gives more lift, but only up to the critical angle of attack. Beyond it the wing stalls, at any speed.

Why Do Planes Fly? How Wings Make Lift, and Why They Stall · Stall recovery

Lift

Lift is the force the wings make as air flows around them, acting at right angles to the flight path. In level flight it balances the weight. It grows with airspeed and angle of attack, up to the stall.

Why Do Planes Fly? How Wings Make Lift, and Why They Stall · Turns

Stall

A stall happens when the wing passes its critical angle of attack: the airflow separates from the wing and lift drops sharply. It can happen at any speed or attitude, and it is about the wing, not the engine.

What Is a Stall in a Plane? Warning Signs and Stall Recovery · Stall recovery

Stall warning

A stall warning shows that the wing is close to its critical angle of attack, before it stalls. It may be a horn, a light, a shaking control column or buffeting. The response is to reduce the angle of attack.

What Is a Stall in a Plane? Warning Signs and Stall Recovery · Slow flight

Flaps

Flaps are hinged panels on the back edge of the wings that the pilot can extend to increase lift and drag. They let the aircraft fly more slowly and descend more steeply for landing, and are raised for cruise.

Traffic pattern

Trim

Trim takes away the steady pressure the pilot would otherwise have to hold on the controls, so the aircraft keeps the chosen attitude by itself. Pilots set the attitude first, then trim.

Controls and trim

Pitch

Pitch is the nose moving up or down, a rotation around the lateral axis from wingtip to wingtip. The pilot controls it with the elevator. Pitch attitude is how far the nose is above or below the horizon.

Controls and trim

Roll

Roll is a rotation around the longitudinal axis, the line from nose to tail, that lowers one wing and raises the other. The pilot controls it with the ailerons, and banking is how an aircraft turns.

Controls and trim

Yaw

Yaw is a rotation around the vertical axis that swings the nose left or right. The pilot controls it with the rudder pedals, mainly to keep the aircraft in balanced flight rather than to steer it in a turn.

Controls and trim

Elevator

The elevator is the movable surface on the horizontal tail that controls pitch. Pulling the control column back raises the nose, and pushing it forward lowers the nose.

Controls and trim

Aileron

Ailerons are the movable surfaces near each wingtip that move in opposite directions to roll the aircraft. Turning the control wheel or moving the stick to the left lowers the left wing and starts a turn to the left.

Controls and trim

Rudder

The rudder is the movable surface on the vertical tail, worked by the pedals, that yaws the nose left or right. Pilots use it to keep the flight balanced and to line up the nose with the runway in crosswinds.

Controls and trim

Throttle

The throttle is the cockpit lever that sets how much power the engine gives: forward for more, back for less. Extra power can become extra speed or a climb, depending on the pitch attitude.

Straight and level

Airspeed

Airspeed is the speed of the aircraft through the air around it, usually shown in knots on the airspeed indicator. The wings depend on it for lift, and it differs from the speed over the ground whenever there is wind.

Climbs and descents

Vertical speed

Vertical speed is how fast the aircraft is climbing or descending, shown in feet per minute on the vertical speed indicator. It reads zero in level flight, above zero in a climb and below zero in a descent.

Straight and level

Attitude indicator

The attitude indicator uses a small aircraft symbol and an artificial horizon to show whether the nose is above or below the horizon and how far the wings are banked. It is the basis of flying by instruments.

Recognise a dive

Rotate

To rotate is to raise the nose during the take-off roll, once the aircraft reaches rotation speed, so the wings can lift it off the runway. The pilot eases the control column back smoothly to the lift-off attitude.

Take-off

Flare

The flare is the last part of a landing, just above the runway, when the pilot gradually raises the nose to reduce the descent rate and the speed. The aircraft then settles gently onto the runway, usually main wheels first.

Landing

Traffic pattern

The traffic pattern is the standard rectangular path that aircraft fly around an airport to take off and land safely and in order. Its legs are upwind, crosswind, downwind, base and final; ICAO calls it the aerodrome traffic circuit.

Traffic pattern

Final approach

Final approach is the last straight part of an approach, lined up with the runway centreline and descending towards it. In the traffic pattern it follows the base leg; on an instrument approach it starts at a charted point.

Landing

Go-around

A go-around means abandoning an approach or landing and climbing away. It is a normal manoeuvre, not a failure, used whenever the approach is not stable or it is not safe to continue to land.

What Is a Go-Around? Why Planes Abort a Landing and Climb Away · Go-around

Crosswind

A crosswind is wind blowing across the runway or the aircraft's path instead of along it. It pushes the aircraft sideways, so pilots correct for it on take-off and landing. The word also names a leg of the traffic pattern.

How Pilots Land a Plane in a Crosswind: Crabbing and Sideslips · Crosswind landing

Crab

To crab is to point the nose into a crosswind just enough to keep the aircraft's track over the ground straight. Before touchdown the nose must be lined up with the runway so the wheels do not touch down sideways.

How Pilots Land a Plane in a Crosswind: Crabbing and Sideslips · Crosswind landing

Sideslip

In a sideslip the pilot lowers the into-wind wing and holds the nose straight with opposite rudder, so the aircraft stops drifting. On a crosswind landing it keeps the aircraft lined up with the runway all the way to touchdown.

How Pilots Land a Plane in a Crosswind: Crabbing and Sideslips · Crosswind landing

ILS

The ILS, or instrument landing system, uses radio beams from the ground to guide aircraft to a runway. Its localizer gives left-right guidance and its glideslope gives up-down guidance, shown on cockpit instruments.

How Planes Land in Fog: The ILS, Approach Categories and Autoland · Autopilot ILS approach

Localizer

The localizer is the part of an ILS that gives left-right guidance along the runway centreline. The display shows whether the aircraft is left or right of that line, and an autopilot can follow it.

How Planes Land in Fog: The ILS, Approach Categories and Autoland · Autopilot ILS approach

Glideslope

The glideslope is the part of an ILS that gives up-down guidance: a radio beam that slopes up from the runway at about 3°. It shows whether the aircraft is above or below the correct descent path.

How Planes Land in Fog: The ILS, Approach Categories and Autoland · Autopilot ILS approach

Decision height

Decision height is the height above the runway on a precision approach, such as an ILS, at which the pilot must decide: continue if the required visual references are in sight, or go around at once if they are not.

How Planes Land in Fog: The ILS, Approach Categories and Autoland · Go-around

Autopilot

An autopilot moves the flight controls automatically to hold an altitude, heading, vertical speed or course chosen by the pilot. It reduces workload, but the pilots must watch what it does and can disconnect it.

What Happens If the Pilots Can't Fly a Passenger Plane? · Hand over to the autopilot

Autothrottle

An autothrottle adjusts engine thrust automatically to hold a selected airspeed or to help the aircraft follow its planned climb or descent. Without it, the pilots set the power by hand; with it, they still monitor the engines.

How to Read the FMA: Autopilot Mode Boxes on an Airliner Display · Read the FMA

FMA

The FMA, or flight mode annunciator, shows which modes the autopilot and autothrottle are using now and which are armed to engage next. Crews check it after every change, because it shows what the automation is really doing.

How to Read the FMA: Autopilot Mode Boxes on an Airliner Display · Read the FMA

Mayday

Mayday is the international radio distress call, said three times at the start of a message. It means grave and immediate danger and a need for help at once, and it has priority over all other radio calls.

What Happens If the Pilots Can't Fly a Passenger Plane? · Hand over to the autopilot