KTAS: Knots True Airspeed and What It Means

If you take planes often, it’s easy to become interested in how they work. Knowing the specifics gives nervous flyers peace of mind while others who love flying want to know as much as possible.

Either way, we have you covered. In this article, we’re explaining KTAS which is pilot lingo for how fast planes fly.

If you want to know more about how planes speed through the air, read on below.

Knots True Airspeed or KTAS

KTAS is the abbreviation for knots true airspeed, a unit of speed measurement. The knots true airspeed tells pilots how fast the plane is going in relation to the air around it. The speed changes based on air pressure, temperature, and weather.

Pilots use knots true airspeed to calculate flight plans, fuel costs and needs, and navigation. In the private plane industry, it’s a factor in calculating flight price. Knots TAS is the equivalent speed of how fast a plane would go on the ground. It’s essentially a planes MPH, measured in knots.

What is a Knot?

A knot is a unit of measurement for large vessels like planes and ships. It’s slightly different from MPH, but not by much. The difference is knots measure speed in nautical miles per hour, instead of normal miles.

One nautical mile per hour equals 1.15 normal miles per hour. The practice of using a different mph system is very old. Before speed indicators were invented, sailors would drag ropes with knots on them behind their boats to measure speed.

Since they’re exactly the same but with a .15 mile length change, why use a different system? Because boats and planes measure distance on lines of latitude and longitude. One nautical mile (knot) is 1 minute of an arc on any line of longitude.

Refresher:

Latitude goes horizontally across the globe, creating lines like LATter rungs. Longitude crosses the globe from pole to pole.

KTAS vs IAS

Knots true airspeed is different than indicated airspeed. KTAS doesn’t account for changes in pressure, while IAS (indicated airspeed) does. Knots true airspeed calculates the speed of the plane without environmental interference, while IAS measures the speed with it.

IAS and knots TAS are similar at low altitude and pressure levels, like at temperate sea level. As the plane rises into the air, it passes through different levels of pressure. IAS measures the degree to which the air pressure is slowing down the plane.

Since it accounts for pressure, IAS will always be lower than the knots true airspeed at higher speeds/altitudes.

Wrapping Up

Knots true airspeed is the way pilots measure nautical miles per hour. It tells them what to plan for time and fuel wise, while IAS is the ever-changing reality.

If you’re looking for a company that can get you to your destination fast, privately, and in luxury, we’ll be happy to tell you more. Our pilots are experts and you’re welcome to ask them questions during your next trip.