What Explains Denver’s Longer Than Average Runways?

Denver International Airport (DEN) is an intercontinental hub situated in the US state of Colorado. It stands out as being North America’s largest airport by surface area, and second in the world only to King Fahd International Airport (DMM) in Dammam, Saudi Arabia. One reason for its large surface area is its extremely long runways, but why does it need these?

What Explains Denver’s Longer Than Average Runways?
Denver is a hub for Chicago-based US legacy carrier United Airlines. Photo: Getty Images

An overview of Denver’s runways

Denver International Airport opened in February 1995, replacing the city’s former Stapleton International Airport. Its first five runways were equal in length. Runways 7/25, 8/26, 16L/34R, 17L/35R, and 17R/35L all measured exactly 12,000 feet long. This distance equates to 3,658 meters, or 2.27 miles. However, they were eventually dwarfed by another landing strip.

September 2003 saw the opening of Denver‘s sixth runway, known as 16R/34L. This concrete strip differed from the existing five runways by being 4,000 feet longer than them. This gave it a total length of 16,000 feet, equivalent to 4,877 meters or 3.03 miles. This astronomically long runway represented a 33% extension compared to the five that had come before it.

Denver Airport
Denver Airport from above. Photo: United States Geological Survey via Wikimedia Commons

However, even these were significantly longer than average in terms of US airports. Indeed, they outranked three of the four runways at Los Angeles International, and two of the four at New York JFK. So why are Denver’s runways, particularly its sixth, so long?

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Why does it need such long runways?

The reason that Denver’s runways are so long is down to the altitude at which the airport is situated. Colorado’s capital is known as the ‘Mile High City,’ and, correspondingly, its airport finds itself situated 1,656 m / 5,434 ft above sea level. This results in a challenging set of atmospheric conditions for pilots known as ‘hot and high.’

Denver Mile High Stadium
Denver’s altitude was also referenced in the name of the Denver Broncos’ former Mile High Stadium.      Photo: Drive-In-Mike via Wikimedia Commons

Low air density is a characteristic of hot and high conditions. This comes about due to a combination of an airport being situated at a high altitude, and prone to hot temperatures. This lack of density reduces lift, as well as impacting the abilities of an aircraft’s engines.

These factors mean that aircraft under such conditions require a higher lift speed to take off. This necessitates a longer runway than if they were departing at a lower altitude to gain this speed. Aircraft with higher power-to-weight rations, such as the Boeing 757, are well-suited to such airports. However, thanks to its long runways, Denver can even handle fully-loaded Airbus A380s and Boeing 747s despite its altitude and associated atmospheric challenges.

Even lengthier examples elsewhere

Although Denver has very lengthy runways, and for a good reason, they are not the world’s longest. Indeed, as Simple Flying explored in July 2020, there are a handful of runways that stretch as far as five kilometers long, and even further.

Denver Airport
A snow-covered Denver Airport. Despite its lengthy runways, longer examples can be found elsewhere.  Photo: ashleyniblock via Wikimedia Commons

For example, China’s Qamdo Bamda Airport used to have a 5,500-meter long landing strip. Much like Denver, this was also necessitated by its extremely high altitude (4,334 m / 14,219 ft above sea level). However, its runway has since been reduced to 4,500 meters long.

Elsewhere, Moscow Zhukovsky boasts a 5,400-meter long runway. Shigatse Peace Airport (China) and Ulyanovsk Vostochny Airport (Russia) also clock in at exactly five kilometers in length. In terms of non-commercial runways, these are dwarfed by the 10,700-meter dry lakebed strips at White Sands Space Harbor in New Mexico.

Did you know about Denver’s longer-than-average runways? Have you ever flown into or out of the Mile High City? Let us know your thoughts and experiences in the comments!

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