Runway Length

Typical commercial runways are between 8,000 and 13,000 feet. Here’s a list of the longest runways in the world – some of them are just over 16,000 feet.

On the other extreme, the shortest runways in the world are hard to calculate, because what constitutes a “runway” can be debatable. A dirt path in the country could technically be considered a runway.

Wikipedia has a list of the shortest runways, and they seem to draw the line at any runway at an aerodrome with an official ICAO code. Under that criteria, the shortest runway is 400 feet long at a facility in Southern Idaho.

How much runway an aircraft needs to take off depends on:

1. the characteristics of the specific aircraft
2. the density of the air at that specific elevation; lower air density at higher elevations provides less lift
3. the wind direction during the takeoff; a headwind increases the relative speed of air over the wings
4. how much the aircraft weighs at that particular time

Obviously, an aircraft with nothing on board doesn’t need as much space as one that’s fully loaded. And this weight is highly variable – a modern airliner can weigh twice as much when loaded as when empty.

Most of an aircraft’s takeoff weight is fuel – a 747 can almost double its weight in fuel alone. It can hold 50,000 gallons of jet fuel, which is about 350,000 pounds, which is almost as much as the empty jet itself.

The Airbus A380 can actually can carry more weight in fuel than the aircraft weighs, and far more than the people onboard. At maximum carrying configuration, an A380 can hold 853 people. If we generously assume each person and their luggage is 300 pounds, this (250,000 lbs.) is still less than half the weight of the fuel (660,000 lbs).

Wikipedia states that:

At sea level, 3,200 m (10,500 ft) can be considered an adequate length to land virtually any aircraft.

Also:

The Boeing 747 is considered to have the longest takeoff distance of the more common aircraft types and has set the standard for runway lengths of larger international airports.

The page for the 747 lists different distances for different versions, but they average a bit over 10,000 feet. The Boeing 737 is currently the most ubiquitous airliner in the world (almost 11,000 have been built). It requires between 6,000 and 8,000 feet to takeoff.

(It’s unclear what configuration these numbers represent. On the page for the CRJ100/200, the takeoff numbers are qualified with “SL, MTOW” which means “[at] sea-level, [at] maximum takeoff weight.”)

In general, planes require less distance to land, due in no small part to the simple fact that they’ve burned most of their fuel and thus weigh much less than when they took off. Aircraft use three methods to slow down after landing:

1. Reverse thrust of the engines
2. Brakes on the landing gear
3. Flaps on the wings

Additionally, the distance required to land is affected by the condition of the runway. A wet runway will not allow as much braking force as a dry runway.

A graph on this page indicates that a unloaded 747 on a dry runway at sea level can land in as short as 5,000 feet.

Private jets are considerably shorter for both takeoff and landing. Fully loaded (MTOW) takeoff distances are 4,000 to 6,000 feet, with landing distances less than 3,000 feet.

The U.S, Air Force’s C17 Globemaster cargo plane requires 8,400 feet to takeoff and 3,500 feet to land at MTOW. This aircraft is specifically designed for short takeoffs and landings.

Why I Looked It Up

I was reading about the Sioux Falls Regional Airport for some reason. It has two main runways, at 9,000 and 8,000 feet, and a smaller one of just over 3,000 feet.

I got wondering is this was “long,” by some measure.

By comparison:

• Chicago O’Hare has eight runways of between 7,500 and 13,000 feet
• Charles De Gaulle airport in Paris has four runways of between 9,000 and 14,000 feet
• Ellsworth AFB in Western South Dakota has a single runway of 13,500 feet (interesting because they support both B-52s and B-2 stealth bombers)
• The private airport in Tea, South Dakota (the nearest airfield to Sioux Falls) has a single runway of 3,650 feet

I remember a 747 landing at Sioux Falls airport a few years ago – it was a charter bringing an local Army National Guard unit back from the Middle East. According to the graph linked above, it would require a maximum of just under 8,000 feet to land (Sioux Falls is about 2,500 feet above sea level).

Since the same plane would have taken off unloaded (given the nature of the flight, it wasn’t taking on passengers or cargo), it could takeoff in much shorter distance. They might also have minimally refueled the plane to keep its weight down for a shorter takeoff roll, then fully refueled at a larger airport.

A forum post on this page quotes a Boeing publication:

Sea level standard day (59 deg F, 29.92 inches Hg), no wind, level runway, air conditioning off (except one pack can be powered by the APU), PW4056 engines: minimum runway length of 5500 ft allows a takeoff weight of 635,000 lb, 6000 ft allows 665,000 lb, then a fairly straight line from there to 10,100 required feet for 850,000 lb.

Again, Sioux Falls is above sea level, but an unloaded 747 only weighs about 380,000 pounds – just over half the number discussed in the calculations above.

I also remember that after an air show in 2002 (or so), a B1 Lancer took off from Sioux Falls airport. I was working in a building downtown, and it literally shook from the force of the plane taking off. I couldn’t find any information on the minimum required runway length from the B1 (that data might be classified).