4 ms·

Very, very few airport runways are long enough for a plane without brakes to land halfway and be fine. It's simply not possible to build airports in useful pla

by SR2Z 2y ago

Very, very few airport runways are long enough for a plane without brakes to land halfway and be fine. It's simply not possible to build airports in useful places and guarantee three-mile runways.

teleforce 2y ago
Apparently runaway excursions is the third cause of major accidents of large commercial transport aircraft [1]. Muan airport runway distance is one the shortest in Korea, less than 3 km and ironically during the incident reportedly there is an ongoing construction to increase the length of the runaway to more than 3 km, but effectively further shorten the runaway to 2.5 km (similar to Yangyang Airport). Strangely South Korea has many shorter runway international airports. Most of the modern international airport have more than 4 km runway, and new major airports for example Qatar Doha, US Denver and SA Upington has runaway length close to 5 km. [1] Operational Landing Distances: A new standard for in-flight landing distance assessment. [2] Muan Airport runway previously shortened, impact under scrutiny: https://m.koreatimes.co.kr/pages/article.asp?newsIdx=389538 https://m.koreatimes.co.kr/pages/article.asp?newsIdx=389538
- FabHK 2y ago
  > new major airports for example Qatar Doha, US Denver and SA Upington has runaway length close to 5 km. These are by no means average "new major airports". Denver airport (from 1989) is the west's largest airport (by land area), and at 5000 ft+ elevation (necessitating longer runways). Upington in the far North-West of South Africa was built in 1968 to accommodate a full Boeing 747 flying to Europe non-stop during the apartheid regime when sanctions meant that overflight or stops in the rest of Africa were not feasible. It has one of the longest runways in the world due to the use case and hot & high environment at 2800 ft (and was intended as an emergency runway for Space Shuttles, if memory serves correctly). It is hardly used anymore with less than 20 aircraft movements a day. There is no recent trend for longer runways. The issue is extremely well known and well understood, by and large.
- usr1106 2y ago
  Denver needs a longer runway because of its altitude. Doha because of the temperatures. It makes no sense to compare their length with locations at more favorable locations.
dredmorbius 2y ago
You don't need the aircraft to survive. You need the passengers to survive. And that's eminently possible, even where the hull itself is destroyed (several cases of fuselages splitting in two or three with no or minimal fatalities): <https://news.ycombinator.com/item?id=42606790 https://news.ycombinator.com/item?id=42606790>
- bagels 2y ago
  The choice of keeping the craft intact is much more likely likely to lead to a safer outcome, isn't it?
  - dredmorbius 2y ago
    It's a vastly more challenging goal, with higher engineering, financial, and land-use requirements. Passenger survivial: Decelleration g-forces kept within a given threshold, evacuation slides operable, passengers cleared within 90 seconds. Hull is sacrificed. Airframe survival: No significant damage to aircraft structure or systems. Humans in this case are substantially more robust than aircraft. You'll find a similar situation in, e.g., earthquake safety construction. The goal isn't for structural reuse, but for inhabitant survivability. Structures may be renovated in some case but are generally demolished and replaced. They did their job in saving lives. Steel-reinforced concrete buildings can still sustain considerable damage, possibly to the point that they will be unusable after the quake. This has to do with the way governments set building codes, which tell engineers how to design a building to withstand a certain level of earthquake shaking. Codes, including those in the U.S. and Turkey, generally require that a building achieves what is called “life safety” under a given maximum expected earthquake in an area. “Our seismic codes are only a minimum requirement,” says Sissy Nikolaou, research earthquake engineer at the National Institute of Standards and Technology. “You just want these buildings at least to give you the chance to get out of it alive when the big one happens, under the assumption that they may be seriously damaged.” The situation is akin to a car that crumples in a crash: the vehicle absorbs the impact to protect passengers, but it is totaled. <https://www.scientificamerican.com/article/how-to-engineer-buildings-that-withstand-earthquakes/ https://www.scientificamerican.com/article/how-to-engineer-b...> The automobile-safety example given above is also apt. A car can be destroyed in a crash, what's key is that its occupants survive.

by SR2Z 2y ago

Very, very few airport runways are long enough for a plane without brakes to land halfway and be fine. It's simply not possible to build airports in useful places and guarantee three-mile runways.

teleforce 2y ago

Apparently runaway excursions is the third cause of major accidents of large commercial transport aircraft [1]. Muan airport runway distance is one the shortest in Korea, less than 3 km and ironically during the incident reportedly there is an ongoing construction to increase the length of the runaway to more than 3 km, but effectively further shorten the runaway to 2.5 km (similar to Yangyang Airport). Strangely South Korea has many shorter runway international airports. Most of the modern international airport have more than 4 km runway, and new major airports for example Qatar Doha, US Denver and SA Upington has runaway length close to 5 km. [1] Operational Landing Distances: A new standard for in-flight landing distance assessment. [2] Muan Airport runway previously shortened, impact under scrutiny: https://m.koreatimes.co.kr/pages/article.asp?newsIdx=389538 https://m.koreatimes.co.kr/pages/article.asp?newsIdx=389538

FabHK 2y ago
> new major airports for example Qatar Doha, US Denver and SA Upington has runaway length close to 5 km. These are by no means average "new major airports". Denver airport (from 1989) is the west's largest airport (by land area), and at 5000 ft+ elevation (necessitating longer runways). Upington in the far North-West of South Africa was built in 1968 to accommodate a full Boeing 747 flying to Europe non-stop during the apartheid regime when sanctions meant that overflight or stops in the rest of Africa were not feasible. It has one of the longest runways in the world due to the use case and hot & high environment at 2800 ft (and was intended as an emergency runway for Space Shuttles, if memory serves correctly). It is hardly used anymore with less than 20 aircraft movements a day. There is no recent trend for longer runways. The issue is extremely well known and well understood, by and large.
usr1106 2y ago
Denver needs a longer runway because of its altitude. Doha because of the temperatures. It makes no sense to compare their length with locations at more favorable locations.

dredmorbius 2y ago

You don't need the aircraft to survive. You need the passengers to survive. And that's eminently possible, even where the hull itself is destroyed (several cases of fuselages splitting in two or three with no or minimal fatalities): <https://news.ycombinator.com/item?id=42606790 https://news.ycombinator.com/item?id=42606790>

bagels 2y ago
The choice of keeping the craft intact is much more likely likely to lead to a safer outcome, isn't it?
- dredmorbius 2y ago
  It's a vastly more challenging goal, with higher engineering, financial, and land-use requirements. Passenger survivial: Decelleration g-forces kept within a given threshold, evacuation slides operable, passengers cleared within 90 seconds. Hull is sacrificed. Airframe survival: No significant damage to aircraft structure or systems. Humans in this case are substantially more robust than aircraft. You'll find a similar situation in, e.g., earthquake safety construction. The goal isn't for structural reuse, but for inhabitant survivability. Structures may be renovated in some case but are generally demolished and replaced. They did their job in saving lives. Steel-reinforced concrete buildings can still sustain considerable damage, possibly to the point that they will be unusable after the quake. This has to do with the way governments set building codes, which tell engineers how to design a building to withstand a certain level of earthquake shaking. Codes, including those in the U.S. and Turkey, generally require that a building achieves what is called “life safety” under a given maximum expected earthquake in an area. “Our seismic codes are only a minimum requirement,” says Sissy Nikolaou, research earthquake engineer at the National Institute of Standards and Technology. “You just want these buildings at least to give you the chance to get out of it alive when the big one happens, under the assumption that they may be seriously damaged.” The situation is akin to a car that crumples in a crash: the vehicle absorbs the impact to protect passengers, but it is totaled. <https://www.scientificamerican.com/article/how-to-engineer-buildings-that-withstand-earthquakes/ https://www.scientificamerican.com/article/how-to-engineer-b...> The automobile-safety example given above is also apt. A car can be destroyed in a crash, what's key is that its occupants survive.