Have you ever sat on a plane waiting to be cleared for take-off and suddenly thought about what might happen if an engine fails as the plane begins to accelerate? For most people, this uncomfortable thought has occurred at least once. But there is no need to panic. V1, alternatively known as the point of no return, is the speed at which take-off can no longer be aborted, even if the engine fails.

The point of no return

Engine failure is never a nice thought, particularly if you're committed to flying. Thankfully, engineers, manufacturers, and pilots have done plenty of calculating, so passengers need not worry.

There are many other things besides engine failure that could cause a pilot to abort take-off and apply the brakes. These include fire, loss of control, adverse weather conditions, or other technical malfunctions. These things can be dealt with by bringing the aircraft to a stop, so long as they happen before V1.

An Airbus A320neo parked at an airport with its engine in full view.
Photo: Airbus

V1 is effectively the point of no return. It is the point at which the plane is committed to taking off. V1 actually refers to a speed. The precise speed of V1 varies based on the plane weight, runway length, wing flap settings, weather, and much more. The exact speed of V1 for each flight is calculated before take-off. For general reference, aircraft like the Airbus A320 and Boeing 737 can have a V1 speed of about 120-140 knots. Meanwhile, larger planes like the A380 and 747 have a V1 speed of 140-150 knots to account for the greater weight onboard.

Once the plane reaches this speed, it becomes unsafe to apply the brakes or reverse thrust and bring the aircraft to a stop. At this point, the plane is committed to attempting take-off, issue or not.

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Rotate

After a pilot has confirmed that V1 has been reached, they will move their hand away from the throttle. Until V1 is reached, the pilot generally keeps their hand on the throttle in case they need to abort for any reason. After V1, it's all about ensuring the aircraft lifts off without issue.

An Air India Airbus A320neo just after take off.
Photo: Airbus

After the pilot removes their hand from the throttle, they can start to lift the plane's nose up. This is also the moment when the front wheels will leave the ground. Vr is the moment at which the aircraft's lift becomes greater than the effect of gravity pulling the plane down. At this stage, the pilot initiates the rotation maneuver by pulling back on the controls.

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Why is V2 important?

The final key speed for take-off is V2. If you're someone who worries about engine failure, this is the most essential speed you should know. V2 is the safety speed that dictates that even if one engine started to fail, the plane would still be able to take off and perform the appropriate emergency procedure to land safely.

V2 is also calculated before each flight as it can be affected by multiple factors, such as wind, total weight, and more. Given that V2 is reached only seconds after V1, the speed is only a few knots higher. For an Airbus A380, V2 speed is typically around 155-170 knots, while it is about 140-150 knots for an A320.

A Qatar Airways Airbus A380-861 flying in the sky.
Photo: Vincenzo Pace | Simple Flying

A plane maintaining a speed of V2 will still reach a height of 35ft off the ground by the end of the runway, clearing most obstacles in its path. When building airports, this height is considered to ensure any surrounding building or structure would not be hit by a plane traveling at V2 speed due to engine failure. In short, V2 is the speed at which an aircraft can safely take off after the point of no return has been reached, even if something goes very wrong.

Should you panic?

Because V1 and V2 are calculated before each flight and are unique to every flight, they are highly accurate. Both speeds are designed to allow for catastrophes like engine failure. Before V1 is reached, take-off can be safely aborted. In the case of V2, once the plane has committed to take off, flight paths are carefully planned so an aircraft can take off, climb, and return to the airport with engine failure at a lower height than normal and still allow for a safe landing.

Indeed, it is relatively common for flights to take off and make emergency landings just minutes later once pilots notice something is wrong during take-off. Earlier this month, a Flybondi Boeing 737-800 was forced to return to Buenos Aires Ezeiza Airport (EZE) after an engine failed soon after take-off, necessitating a return to the airport.

A Flybondi Boeing 737-800 parked at an airport gate.
Photo: Flybondi

However, returning to the airport can be more complex than just a simple loop and a turn-back. While airspace traffic is cleared the instant a flight reports (or "squawks") an emergency, an overweight landing can result in a hard landing. Hard landings can lead to serious future airframe integrity issues, and pilots are instructed to avoid these unless the failure is catastrophic.

Planes can usually go hours on just one engine, allowing for a key process on some larger planes: fuel dumping. Of course, dumping also has critical issues, including environmental factors and dangers to those on the ground, but it is essential to prevent hard landings. As usual, pilots are discerning with these procedures and follow strict safety protocols during a diversion.

In summary, we would recommend not to panic. Planemakers, regulators, airlines, and pilots spend countless hours simulating every possible failure, so there is always a detailed set of instructions to ensure your safe return to the ground.

Has your flight ever faced an engine failure? Let us know in the comments.