What Does “Retard” Mean in Aviation?

In aviation, “retard” means reduce engine thrust to idle. It is a technical verb, not an insult, and the RETARD you hear in Airbus cockpit videos is an automatic reminder to pull the thrust levers back to their idle stop as the aircraft lands.

Airbus jets say it out loud. Boeing jets display the same word silently on a cockpit screen. Both describe one identical action: thrust to idle, in the last seconds before the wheels touch.

Airbus publishes the trigger height as 20 feet above the runway on a normal manual landing, and describes the callout as a reminder rather than an order. The pilot is free to close the thrust levers earlier.

Question	Answer
What it means	Move the thrust levers to idle
Who says it aloud	Airbus A320, A330, A340, A350 and A380
Boeing equivalent	RETARD shown on the flight mode annunciator, no voice
When it triggers (Airbus)	About 20 feet above the runway on a manual landing
Why it exists	Airbus thrust levers do not move on their own, so there is nothing to see
If the pilot ignores it	Ground spoilers may not extend automatically and the landing runs long
Is it an insult	No. It comes from the Latin retardare, meaning to slow down

What Does “Retard” Mean in Aviation?

Retard is a verb meaning to slow or delay something. Merriam-Webster defines it as “to slow up especially by preventing or hindering advance or accomplishment,” the same sense used in “fire retardant.”

Applied to an aircraft, it means moving the thrust levers aft to reduce the power the engines are producing. Advance the levers and thrust goes up. Retard them and thrust comes down.

The word is standard industry English, not an Airbus invention. The FAA uses it in regulatory documents, describing the Boeing 737 autothrottle’s “landing flare retard mode” in Airworthiness Directive 2014-16-14.

Pilots hear it in training long before they hear it in an Airbus. “Retard the throttle” is the ordinary instruction for closing the power during the landing flare, in a Cessna as much as in an airliner.

Why Do Planes Say “Retard” When Landing?

Because on an Airbus, the thrust levers do not move by themselves, so the pilot gets no physical cue that it is time to close them.

The Airbus A320 was the first airliner built around full fly-by-wire flight controls, and its autothrust system follows the same logic. The engine computers set whatever thrust is needed while the levers stay parked in a fixed detent.

For almost the entire flight, that detent is CL, for climb. The levers sit there unmoving from shortly after takeoff until the flare, no matter how much the engines are actually producing.

That creates the one moment where a reminder genuinely earns its place. Because nothing has moved for the last two hours, the aircraft speaks up at 20 feet to prompt the closing action that has to happen before touchdown.

Airbus is explicit about the status of that prompt. In its Safety First article on the landing flare, the manufacturer states that “the 20 ft ‘RETARD’ auto callout is a reminder, not an order.”

What Retard Means When Landing an Airplane

It means one thing for the pilot: both thrust levers back to the idle stop, by touchdown at the latest.

That matters far beyond the engines. Airbus states that pilots “must ensure that the thrust levers are at idle in any case, by touchdown at the latest, to enable automatic extension of the ground spoilers.”

Ground spoilers are the panels that pop up across the wing on landing to dump lift and plant the aircraft’s weight on its wheels. Without weight on the wheels, the brakes have far less to work with.

Leaving the levers up carries a second cost. Airbus notes that a late retard “may increase the landing distance because the autothrust will target Vapp or the selected speed until it is disconnected,” so the aircraft keeps flying its approach speed and floats down the runway.

50, 40, 30, 20, Retard: The Full Landing Callout Sequence

The RETARD callout is the last item in a countdown, which is why cockpit videos capture it as part of a run of numbers rather than on its own.

Those numbers are radio height, not altitude above sea level. A radio altimeter measures the distance from the aircraft’s belly to whatever is directly underneath it, so “fifty” means fifty feet above the runway surface.

On a typical manual Airbus landing the sequence runs “fifty, forty, thirty, twenty,” and then “retard, retard.” The word repeats until the levers reach idle, which is why it often sounds insistent in videos.

The exact trigger height is not fixed across every situation. On a fully automatic landing, where the autopilot flies the ILS approach all the way to the runway, the autothrust starts reducing power during the flare and the callout comes later in the countdown.

Automated calls like this exist because a landing is the busiest 30 seconds of a flight. They free the pilot monitoring to watch the wider picture instead of reading out every height.

Boeing Says Retard Too, It Just Does Not Say It Out Loud

The callout is famous as an Airbus quirk, but Boeing aircraft use the identical word. They show it rather than speak it.

On a Boeing flight mode annunciator, RETARD appears in the thrust mode field when the autothrottle is commanding power back for landing. It is text on a screen, with no voice attached.

Boeing does not need the aural prompt because its autothrottle is back-driven. Servos physically pull the thrust levers aft, so the pilot’s hand feels the movement and can see it happen.

That is the whole design difference in one sentence. Boeing moves the levers and lets the pilot watch, while Airbus leaves the levers still and tells the pilot instead.

When Retard Mode Fired Too Early: Turkish Airlines 1951

The clearest illustration of why retard logic is guarded so carefully is an accident in which it activated at the wrong moment.

On 25 February 2009, Turkish Airlines Flight 1951, a Boeing 737-800, was approaching Runway 18R at Amsterdam Schiphol. As the aircraft descended through 2,000 feet, the captain’s left radio altimeter jumped to a reading of minus 8 feet.

The autothrottle believed the aircraft was on the runway. It switched from holding 160 knots into retard flare mode and pulled the engines to approach idle, thousands of feet too early.

The autopilot kept raising the nose to stay on the glideslope while the speed bled away unnoticed. The stick shaker fired at 460 feet, far too low to recover, and the aircraft struck terrain 0.8 nm short of the runway.

Five passengers, a flight attendant and all three pilots were killed, and 120 more people were injured. The Dutch Safety Board concluded that the crew should have flown a go-around once the approach became unstable.

The regulatory answer came in 2014. FAA Airworthiness Directive 2014-16-14 required operators of the 737-600, -700, -700C, -800 and -900 to replace the autothrottle computer, so that one bad radio altimeter output could no longer trigger premature retard on its own.

Is “Retard” Offensive? Why Airbus Still Uses the Word

This is the real reason the phrase goes viral, and the honest answer is that the aviation word and the slur are separate uses of the same root that arrived at very different places.

Retard comes from the Latin retardare, to slow down, and reached English through French. Engineering kept the plain mechanical meaning, which is why spark timing is retarded in a car engine and why a chemical that slows a fire is a retardant.

In the cockpit it is a description of a lever position, addressed to a machine action rather than to a person. Nobody in the crew is being called anything.

The callout has also stayed. It remains standard across the current Airbus range, from the A320 family through the A330, A340, A350 and A380, and it is one of the most recognizable sounds in modern commercial flying.