Takeoffs are complex flight procedures that involve many different steps. Pilots, for instance, must calculate an appropriate speed. Airplanes must fly fast enough to generate sufficient lift. Otherwise, they won’t be able to take off.
V1 is one of the most important speeds in the takeoff process. Not to be confused with airspeed, it helps pilots make smarter decisions when taking off. Pilots use V1 to decide whether to continue or abort the takeoff. To learn more about V1 in aviation, keep reading.
What Is V1?
Also known as takeoff decision speed, V1 is the speed at which a takeoff can no longer be aborted. As long as an airplane is traveling slower than its V1, pilots can abort the takeoff. Upon reaching the airplane’s V1, however, pilots must commit to the takeoff process.
V1 is typically measured in knots. If an airplane has a V1 of 100 knots, it can travel at speeds slower than 100 knots when taking off while still giving the pilot the option of aborting.
Factors That Affect V1
Several factors can affect an airplane’s V1, one of which is the airplane’s weight. Heavy airplanes require more runway space to take off, as well as land, than lighter airplanes. Therefore, heavy airplanes typically have a higher V1.
The length of the runway will affect an airplane’s V1. Runways, of course, can vary in length. Some are just 2,000 to 3,000 feet long, whereas others are 10,000 to 15,000 feet long. The longer the runway, the higher the V1.
Thrust can affect an airplane’s V1. Higher available thrust allows airplanes to accelerate more quickly. They can achieve takeoff speed in a shorter distance, which often translates into a higher V1. If available thrust is reduced, on the other hand, the airplane will accelerate more slowly, resulting in a lower V1.
Why V1 Is Important
V1 is important because it tells pilots the speed at which they must fully commit to the takeoff. Once an airplane has reached this speed, the pilot can no longer abort the takeoff. Rather, they must continue to take off — even if there’s a mechanical problem.
Research shows that nearly one in five rejected takeoff incidents involve attempts to abort after passing V1. If a pilot attempts to abort the takeoff after reaching or exceeding the V1, an overrun may occur. Incidents such as overruns can often be avoided, though, by carefully monitoring the airplane’s takeoff speed in relation to the V1.
