INTRODUCTION
The sky hosts two very different tribes of aircraft. On one side, you have commercial jets - the calm, well-mannered giants that ferry people from Delhi to Dubai while quietly pouring out juice at 36,000 feet. On the other hand, you have fighter jets- compact rockets wearing wings, built to twist through the air like they’re late for a very dangerous appointment, and somewhere between these two worlds lives a fiery invention that belongs squarely to one side.
Have you looked at a fighter jet and felt amused by how quickly it flies by? The loud sound produced by the jet, along with the bright flame shooting out from its engine, is always a catch. On the contrary, a commercial flight flies by swiftly and silently. This brings us to the question: what sets these two types of aircraft apart? The simple answer is afterburner.
Now picture this: you’re settling into your aisle seat on an Indigo A320, tray table up, seat belt clicked, the usual safety demo humming in the background, and suddenly the aircraft lights dim like a haunted house because the engines have just kicked into afterburner mode. But try imagining an Indigo flight with afterburners: cabin lights flickering, and everyone’s headphones vibrating off their ears. Not exactly customer-friendly. Afterburners are thrilling, but only when you aren’t holding a cup of tea at the same time.
WHAT IS AN AFTERBURNER?
An afterburner, sometimes called a reheat system, is an extra part fitted at the back of a jet engine. It is a thrust-boosting component installed in the engines of many high-performance military aircraft.
Once the fuel has already been burned inside the main engine, an afterburner works by spraying extra fuel into the hot exhaust of a jet engine and igniting it, creating a second burst of combustion for extra thrust. It is designed to provide a rapid, temporary increase in power by injecting additional fuel into the jet pipe and igniting it in the engine’s exhaust stream. This creates a powerful thrust boost in a matter of seconds. It helps fighter jets accelerate quickly.
The concept can be likened to a gas stove: when the gas knob is abruptly turned to maximum and ignited near the outlet, a powerful flame emerges. This is what happens in the case of a fighter jet, too. Afterburner achieves rapid acceleration, which helps jets fly faster than the speed of sound. Although extremely fuel-intensive, an afterburner can increase an engine’s thrust by up to 50–70%, making it indispensable for combat, supersonic flight, and rapid takeoffs.
WHY DO FIGHTER JETS NEED AFTERBURNERS?
Fighter jets operate in some of the most demanding environments imaginable. They must accelerate instantly, climb rapidly, and outmaneuver threats within seconds. To meet these extreme performance requirements, modern fighter aircraft rely on afterburners. The purpose of fighter jets is to serve in combat situations; it is of utmost importance to attain speed, agility, and power to function, to perform all the functions that a normal jet is not capable enough. This is where the afterburner serves its purpose. It gives the sudden push that is needed to speed up the jet to attain supersonic speeds.
To understand the function of afterburners, we will discuss the most important aspect of a fighter jet:
INSTANT ACCELERATION IN COMBAT: In air combat, timing isn’t measured in minutes; it’s measured in fractions of a second. The pilot who can change speed faster often gains the upper hand. This is where afterburners become indispensable.
When a fighter jet activates its afterburner, it produces an immediate surge of thrust. This allows the aircraft to jump from one energy state to another almost instantly. In practical combat scenarios, that sudden acceleration can influence several key outcomes:
i) Escaping Enemy Missiles
Modern air-to-air missiles are fast, agile, and guided by advanced sensors. To dodge them, a pilot may need to create sudden distance or perform high-speed maneuvers. When a missile is launched at a fighter jet, the pilot has only moments to react. Modern missiles are equipped with heat-seeking or radar-guided systems and can adjust their path mid-flight, making them incredibly difficult to outrun through normal engine power alone.
This is where the afterburner becomes a lifesaver. By injecting additional fuel into the exhaust, the jet produces a rapid surge in thrust, allowing it to accelerate far faster than the missile anticipates. This sudden burst of speed helps increase the distance between the jet and the missile, forcing the missile to burn more energy and attempt sharper corrections, often causing it to lose lock or fall short.
- The added acceleration also gives the aircraft the energy needed to perform high-G maneuvers, like hard turns or vertical climbs, which further disrupt the missile’s guidance system. In essence, afterburners give pilots the split-second advantage required to stretch or break engagement geometry and survive an otherwise lethal encounter.
ii) Gaining Positional Advantage
Winning an air battle is often about securing the right angle rather than just raw speed. Combat between two fighter jets is a constant struggle to achieve a position behind the enemy, known as the “control zone,” where weapons can be deployed effectively. Afterburners allow pilots to manipulate this geometry with precision.
When activated, they provide immediate acceleration that can shrink the distance between opposing aircraft, helping a pilot catch an enemy trying to escape or extend. In turning engagements, the extra thrust can be used to maintain higher energy levels, allowing the aircraft to climb, roll, or bank more aggressively without bleeding off too much speed. This is crucial because air combat revolves around maintaining energy superiority; whichever pilot has more speed and altitude can dictate the fight.
A quick burst of afterburner can help a pilot slip from a disadvantaged line to a neutral one, and from neutral into an offensive position. By rapidly adjusting speed, angle, and altitude, the jet gains the upper hand, locking the opponent into a defensive spiral and setting up for a potential missile shot or gun pass.
iii) Recovering from Energy Loss during Operations
Every major maneuver in aerial combat - sharp turns, climbs, barrel rolls, breakaways costs energy. As a fighter jet pulls high “G” forces during tight turns, it loses speed dramatically. If a pilot cannot regain this speed quickly, the aircraft becomes sluggish, less maneuverable, and vulnerable to enemy fire.
Afterburners act as an instant energy refill, giving the aircraft the power needed to recover lost velocity in seconds. This matters because momentum determines how sharply and how long a jet can continue maneuvering. Without this rapid acceleration, the aircraft could stall out of a turn or fail to climb in time, giving the enemy a clear shot. Engaging the afterburner restores the aircraft’s ability to maintain offensive pressure or break away from danger after a demanding maneuver. It ensures the jet doesn't fall behind in the constant energy tug-of-war that defines dogfighting.
WHY DO COMMERCIAL JETS NOT USE AFTERBURNERS?
The purpose of designing commercial jets is very different from that of fighter jets. These jets are entrusted with the responsibility of carrying hundreds of people across thousands of kilometres. These aircraft do not run at supersonic speeds but rather maintain a steady speed to ensure the safety of both the passengers and the aircraft.
Additionally, commercial flights fly over cities and hover over residential areas; using afterburners would emit loud noise and pollution into the environment. This would be extremely harmful and would not be appreciated by residents of areas near the airport.
The implementation of afterburners in commercial jets would drastically increase ticket prices due to the substantial fuel consumption associated with such technology. Some major reasons why Commercial Jets do not utilise afterburners are:
1. Afterburners Consume Enormous Amounts of Fuel
The biggest reason airlines avoid afterburners is simple: fuel efficiency. Activating an afterburner can multiply fuel consumption by four to ten times. Commercial aviation already operates on razor-thin margins, and fuel is one of its biggest expenses. If airliners used afterburners, a typical two-hour flight could burn enough fuel for an entire day’s worth of operations. For airlines, that’s financially impossible.
2. They Produce Extreme Noise and Heat
Afterburners create massive flames and a thunderous roar, the kind you hear during a fighter jet takeoff.
Imagine every passenger plane at Mumbai, Delhi, or Heathrow sounding like a rocket launch. It would violate noise regulations instantly, disturb surrounding communities, and make airports unmanageable.
Commercial travel requires quiet, controlled operations, not fire-belching engines.
3. Commercial Jets Don't Need the Extra Thrust
Airliners have long runways and engines optimized for gradual, controlled takeoff. They don’t need an explosive push to lift off the ground, because:
- They aren’t carrying missiles, commercial flights are supposed to be laid back and relaxed, giving passengers a smooth journey experience; for that reason, commercial flights do not require extra thrust to rush, but rather keep their journey relaxed and at a decent pace.
- They aren’t dodging threats. Commercial jets don’t need afterburners because they aren’t dodging missiles or outmaneuvering enemy aircraft; their biggest mid-air threat is usually a patch of turbulence.
- They don’t operate in combat zones; the purpose of commercial jets is to carry passengers from point A to B. the routes chosen are safe and free from any hindrance.