F-15A Eagle landing with its dorsal speed brake extended

Speed Brakes Explained: How Fighter Jets and Airliners Slow Down

by Max Grünwald | Sep 27, 2026 | Aviation World, Military Aviation | 0 comments

Watch an F-15 Eagle come in to land and you will see a large panel rise up on its back, just behind the cockpit, like a door opening into the airflow. It is the speed brake, and on the Eagle it is big enough to earn the nickname barn door. It exists for one reason: a clean, powerful jet does not like to slow down.

Speed brakes, also called air brakes, are among the simplest devices on an aircraft and among the most used. Here is how they work, why jets need them more than propeller aircraft, and why every type seems to put them somewhere different.

Quick Facts

What: Panels that extend into the airflow to add drag, then retract flush with the airframe
Purpose: Slow down, steepen a descent without gaining speed, or keep engine power up on approach
Why jets need them: Jet engines lack the natural braking effect of a windmilling propeller
Speed brake vs spoiler: A true air brake adds drag with little effect on lift; a spoiler kills lift as well
Fighter examples: F-15, F/A-18 and Su-27 behind the cockpit; F-16 split panels beside the nozzle
Tail-cone examples: Blackburn Buccaneer, Fokker F28, British Aerospace 146
MiGFlug connection: The L-39 Albatros has side-by-side airbrakes under the fuselage

Why Jets Need Them

A propeller aircraft slows down quite naturally when the pilot pulls the power back: the propeller itself creates drag. A jet engine does not, and a streamlined jet can take a long time to lose speed, especially while descending. According to Wikipedia's summary, this lack of propeller braking is exactly why air brakes are so important for jets during approach and descent.

Former F-15 pilot Paul Woodford, who flew the Eagle from 1978 to 1985, puts it plainly.

“The F-15 is a clean airplane, reluctant to slow down with reduced power alone; you used the speedbrake all the time...”

Paul Woodford — former USAF F-15 pilot, writing on his blog Paul's Thing

Speed brakes also let a pilot keep the engines at a higher power setting on approach. Jet engines take time to spool up from idle, so it can be safer to fly the approach with more thrust and more drag, ready to go around quickly if needed.

“Its name is its purpose: you use it to slow down, or... to dirty up the aircraft during landing so you can keep a higher power setting on the engines...”

Paul Woodford — former USAF F-15 pilot

An F-15E Strike Eagle demonstrates aerodynamic braking on landing, holding its nose high with the speed brake up. Video: Mach1Airspace

Behind the Cockpit, Beside the Nozzle

Designers put speed brakes wherever they can add drag without upsetting the aircraft. On the F-15, the F/A-18 Hornet and the Su-27 Flanker, a single large panel sits on the upper fuselage behind the cockpit.

The F-16 does it differently: its speed brakes are split panels on either side of the engine nozzle that open like a clamshell. The Convair F-89 Scorpion used decelerons, split ailerons that open top and bottom, and the B-2 Spirit uses the same principle on its wingtips.

F-16 speed brake panels beside the engine nozzle — The F-16's split speed brake panels sit on either side of the engine nozzle, visible here on a 416th Flight Test Squadron jet at Red Flag. US Air Force photo / Wikimedia Commons, public domain

The Airliners With Opening Tails

Some aircraft open their tails. The Blackburn Buccaneer naval strike jet had a split tail cone that opened sideways, which also shortened the aircraft for stowage on a carrier deck. The Fokker F28 and the British Aerospace 146 use the same idea: the rear of the fuselage opens into two petals on approach, which helps the 146 fly the steep approaches needed at short, city-centre airports.

BAe 146-300 landing with tail airbrakes open — A British Aerospace 146-300 on approach with its tail-cone airbrakes open. The two petals at the rear of the fuselage add drag without affecting the wing. Photo: Wikimedia Commons, public domain

Most modern airliners have no separate air brake at all. Instead they use their wing spoilers. In flight, pilots can raise the spoilers part way to increase the rate of descent, and pilots and manufacturers routinely call this the speed brake, even though spoilers also reduce lift. On landing, ground spoilers, or lift dumpers, deploy fully to kill lift, put weight on the wheels and make the wheel brakes more effective.

Captain Joe explains speed brakes and flight spoilers on an airliner. Video: Captain Joe

From Dive Bombers to Trainers

Air brakes date back to the early days of aviation, and they became vital for dive bombers in the Second World War. A dive bomber needed to point almost straight down at its target without accelerating to dangerous speed. Aircraft such as the Ju 87 Stuka and the SBD Dauntless had dive brakes on their wings, and the Dauntless's were famously perforated to reduce buffeting. Gliders use air brakes too, to control their approach angle without an engine to adjust.

If you fly with MiGFlug in the L-39 Albatros, you may feel them at work: the L-39 has two side-by-side airbrakes under the fuselage, ahead of the wing. Ask your instructor to pop them on the way back to the airfield and you will feel the jet decelerate and settle.

The differences between speed brakes, ground spoilers and roll spoilers. Video: JxJ Aviation

Sources: Wikipedia (Air brake, Spoiler, Aero L-39 Albatros), Paul Woodford (Paul's Thing), SlashGear

Frequently Asked Questions

What is a speed brake on an aircraft?

A speed brake, or air brake, is a panel that extends into the airflow to increase drag, then retracts flush with the airframe. Pilots use speed brakes to slow down, to descend more steeply without gaining speed, or to keep engine power higher during an approach.

Why do jets need speed brakes?

Jet engines lack the natural braking effect of a windmilling propeller, so a streamlined jet can take a long time to lose speed, especially in a descent. Speed brakes add drag on demand, which makes slowing down and managing an approach much easier.

What is the difference between a speed brake and a spoiler?

A true speed brake adds drag while having little effect on lift. A spoiler sits on the upper wing and destroys lift as well as adding drag. On airliners, pilots often call the in-flight use of spoilers the speed brake, even though the spoilers also reduce lift.

Where is the speed brake on an F-15?

The F-15 Eagle has a single large speed brake on the upper fuselage behind the cockpit, sometimes nicknamed the barn door. The F/A-18 Hornet and Su-27 Flanker use a similar dorsal panel, while the F-16 has split speed brakes on either side of its engine nozzle.

Why does the BAe 146 tail open on landing?

The British Aerospace 146, like the Fokker F28, has a tail cone that splits into two petals to act as an air brake. It adds drag without affecting the wing, helping the aircraft fly steep approaches into short airports while keeping engine power up.

Does the L-39 Albatros have speed brakes?

Yes. The Aero L-39 Albatros jet trainer has two side-by-side airbrakes under the fuselage, ahead of the wing leading edge. Passengers on L-39 jet flights can feel the aircraft decelerate when the pilot extends them.