4 ms·

Some countries maintain special segments of highways specifically for aircraft operation: https://en.wikipedia.org/wiki/Highway_strip https://en.wikipedia.org/w

by zokier 4y ago

Some countries maintain special segments of highways specifically for aircraft operation: https://en.wikipedia.org/wiki/Highway_strip https://en.wikipedia.org/wiki/Highway_strip Apparently they are uncommon in US? I guess there are enough general airstrips and open space to make them not necessary

gpderetta 4y ago
I guess these were mostly built in Europe for warplanes, in preparation of a conflict between NATO and USSR, with the expectation that most military airports would be out of commissions after the initial exchanges.
- jltsiren 4y ago
  I think it's more about protecting the aircraft, which are vulnerable on the ground. If you disperse your air force, your casualties will be lower when the enemy attacks your bases.
- ano-ther 4y ago
  Wouldn’t they be kind of obvious targets too?
  - gpderetta 4y ago
    Sure, but the more viable landing strips you have, the more are likely to be viable at anyone time. I understand that Ukraine put to good use its highways after the initial Russian attack that temporarily put out of order many of its airports.
jefftk 4y ago
"The highway strips can be converted from motorways to airbases typically within 24 to 48 hours." Sounds like it wouldn't work for an emergency landing?
- zokier 4y ago
  Idk what that is referring to, the ones I've seen have been mostly straight segments with extended shoulders (and I suppose reinforced beneath but that is difficult to eyeball); definitely something that could be used in emergency without any prep.
  - rob74 4y ago
    At least in Germany, highways have a pretty sturdy central divider - either concrete blocks or steel guardrails, definitely not something you'd want near your landing gear or fuel tanks. They can be removed in a few days if needed, but while they're still there, I wouldn't recommend trying to land.
- Xylakant 4y ago
  They have a few properties that could make them more attractive for emergencies. There are no objects around the highway that would interfere with wings, especially no overpasses, poles or trees. The stretches are long and straight, as well as reasonably flat. The road surface was/is kept in a good enough condition for planes to land. There’s still the middle barrier etc., so in a planned conversion that would be removed, a control tower of sorts set up etc. But in todays traffic, you’d probably not find a gap large enough to squeeze an airliner in. And I don’t think these are still maintained as air strips, at least in Germany.
  - rob74 4y ago
    This German Wikipedia article has a list of all "Autobahn-Behelfslandeplätze", and it looks like out of originally 29, only 9 are still usable: https://de.wikipedia.org/wiki/Notlandeplatz_auf_Stra%C3%9Fe#Autobahn-Behelfslandepl%C3%A4tze https://de.wikipedia.org/wiki/Notlandeplatz_auf_Stra%C3%9Fe#... Trivia: Ramstein Air Base was originally also an autobahn air strip used by the nazis during the last months of the war, then the US forces occupied it, and the autobahn had to be rerouted.
- SkyPuncher 4y ago
  Based on the images, it still would. You might just end up with damage to a wing or engine. Wider runways also make it easier to land/takeoff in a wider range of weather conditions. If you plan to routine use something, it's worth removing the barriers.
local_crmdgeon 4y ago
The issue is weight - state highways are frequently used for landings in Alaska. That doesn't mean they're good to go for a 737.
- dsfyu404ed 4y ago
  This is misleading. Road weight limits are for wear and tear reasons, not safety. The actual "failure" loads are orders (yes, plural) of magnitude higher and most failures aren't the kind of catastrophic thing that people on the internet typically try and imply unless you get really unlucky and your mountainside shelf road turns into a landslide. Failure usually means you park a heavy object somewhere and come back hours/days/weeks/months later and find that it sank or slid slowly downhill in that time.
  - local_crmdgeon 4y ago
    If you land an a380 on I35 at an emergency speed, it will punch right through. Runways are extremely serious pieces of engineering.
    - dsfyu404ed 4y ago
      Bullshit. Straight bullshit. Stop it. Short of maybe, maybe, landing a fully laden C5 on everglade highway or redefining landing to include crashes where the tires happen to be the first bit to crash you are going to have a hell of a time displacing the road bed a meaningful amount with an aircraft without destroying the aircraft. They are simply not strong. They have to be light enough to fly you know. Never-mind the fact that they used to fly these things off of dirt strips... At best you might displace the asphalt a little and leave some ruts behind you. Remember, these are vehicles on pneumatic tires. Their point loads aren't high enough to really cut through pavement. All you can do it smoosh it out of the way. And the road bend was made of gravel of particular size and roughness and then gone over with compacting equipment to prevent exactly that from happening, albeit over time.
- AlbertCory 4y ago
  Indeed. The hugely popular Cessna 172 weighs less than most cars, though: https://en.wikipedia.org/wiki/Cessna_172 https://en.wikipedia.org/wiki/Cessna_172
bell-cot 4y ago
The US Air Force experimented a bit with highway landings (in the US) recently: https://www.af.mil/News/Article-Display/Article/2721902/a-10s-land-on-michigan-state-highway/ https://www.af.mil/News/Article-Display/Article/2721902/a-10...
jcrawfordor 4y ago
The US embarked on a huge effort in the early airmail days to build enough airports that aircraft could follow federal airways without ever being out of glide range of one of them - these were the CAA intermediate fields, many of them not much more than a grass strip with a beacon, but many others were built up over time and remain municipal airports today. Later, WWII lead to the construction of even more airfields for pilot training. So many pilots were being trained that the training bases didn't have the capacity for the pattern practice, so many training airfields had multiple "outlying fields" that were just extra sets of runways a few miles away. Some of these turned into municipal airports later, but many more were abandoned for lack of need. By the time the freeway system was built, the US was positively lousy with airports, much denser than seen in most other countries.

by zokier 4y ago

gpderetta 4y ago

I guess these were mostly built in Europe for warplanes, in preparation of a conflict between NATO and USSR, with the expectation that most military airports would be out of commissions after the initial exchanges.

jltsiren 4y ago
I think it's more about protecting the aircraft, which are vulnerable on the ground. If you disperse your air force, your casualties will be lower when the enemy attacks your bases.
ano-ther 4y ago
Wouldn’t they be kind of obvious targets too?
- gpderetta 4y ago
  Sure, but the more viable landing strips you have, the more are likely to be viable at anyone time. I understand that Ukraine put to good use its highways after the initial Russian attack that temporarily put out of order many of its airports.

jefftk 4y ago

"The highway strips can be converted from motorways to airbases typically within 24 to 48 hours." Sounds like it wouldn't work for an emergency landing?

zokier 4y ago
Idk what that is referring to, the ones I've seen have been mostly straight segments with extended shoulders (and I suppose reinforced beneath but that is difficult to eyeball); definitely something that could be used in emergency without any prep.
- rob74 4y ago
  At least in Germany, highways have a pretty sturdy central divider - either concrete blocks or steel guardrails, definitely not something you'd want near your landing gear or fuel tanks. They can be removed in a few days if needed, but while they're still there, I wouldn't recommend trying to land.
Xylakant 4y ago
They have a few properties that could make them more attractive for emergencies. There are no objects around the highway that would interfere with wings, especially no overpasses, poles or trees. The stretches are long and straight, as well as reasonably flat. The road surface was/is kept in a good enough condition for planes to land. There’s still the middle barrier etc., so in a planned conversion that would be removed, a control tower of sorts set up etc. But in todays traffic, you’d probably not find a gap large enough to squeeze an airliner in. And I don’t think these are still maintained as air strips, at least in Germany.
- rob74 4y ago
  This German Wikipedia article has a list of all "Autobahn-Behelfslandeplätze", and it looks like out of originally 29, only 9 are still usable: https://de.wikipedia.org/wiki/Notlandeplatz_auf_Stra%C3%9Fe#Autobahn-Behelfslandepl%C3%A4tze https://de.wikipedia.org/wiki/Notlandeplatz_auf_Stra%C3%9Fe#... Trivia: Ramstein Air Base was originally also an autobahn air strip used by the nazis during the last months of the war, then the US forces occupied it, and the autobahn had to be rerouted.
SkyPuncher 4y ago
Based on the images, it still would. You might just end up with damage to a wing or engine. Wider runways also make it easier to land/takeoff in a wider range of weather conditions. If you plan to routine use something, it's worth removing the barriers.

local_crmdgeon 4y ago

The issue is weight - state highways are frequently used for landings in Alaska. That doesn't mean they're good to go for a 737.

dsfyu404ed 4y ago
This is misleading. Road weight limits are for wear and tear reasons, not safety. The actual "failure" loads are orders (yes, plural) of magnitude higher and most failures aren't the kind of catastrophic thing that people on the internet typically try and imply unless you get really unlucky and your mountainside shelf road turns into a landslide. Failure usually means you park a heavy object somewhere and come back hours/days/weeks/months later and find that it sank or slid slowly downhill in that time.
- local_crmdgeon 4y ago
  If you land an a380 on I35 at an emergency speed, it will punch right through. Runways are extremely serious pieces of engineering.
  - dsfyu404ed 4y ago
    Bullshit. Straight bullshit. Stop it. Short of maybe, maybe, landing a fully laden C5 on everglade highway or redefining landing to include crashes where the tires happen to be the first bit to crash you are going to have a hell of a time displacing the road bed a meaningful amount with an aircraft without destroying the aircraft. They are simply not strong. They have to be light enough to fly you know. Never-mind the fact that they used to fly these things off of dirt strips... At best you might displace the asphalt a little and leave some ruts behind you. Remember, these are vehicles on pneumatic tires. Their point loads aren't high enough to really cut through pavement. All you can do it smoosh it out of the way. And the road bend was made of gravel of particular size and roughness and then gone over with compacting equipment to prevent exactly that from happening, albeit over time.
AlbertCory 4y ago
Indeed. The hugely popular Cessna 172 weighs less than most cars, though: https://en.wikipedia.org/wiki/Cessna_172 https://en.wikipedia.org/wiki/Cessna_172

bell-cot 4y ago

The US Air Force experimented a bit with highway landings (in the US) recently: https://www.af.mil/News/Article-Display/Article/2721902/a-10s-land-on-michigan-state-highway/ https://www.af.mil/News/Article-Display/Article/2721902/a-10...

jcrawfordor 4y ago

The US embarked on a huge effort in the early airmail days to build enough airports that aircraft could follow federal airways without ever being out of glide range of one of them - these were the CAA intermediate fields, many of them not much more than a grass strip with a beacon, but many others were built up over time and remain municipal airports today. Later, WWII lead to the construction of even more airfields for pilot training. So many pilots were being trained that the training bases didn't have the capacity for the pattern practice, so many training airfields had multiple "outlying fields" that were just extra sets of runways a few miles away. Some of these turned into municipal airports later, but many more were abandoned for lack of need. By the time the freeway system was built, the US was positively lousy with airports, much denser than seen in most other countries.