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When the towers were first built, one of the design questions was whether or not they could survive being hit by a 747 — on accident, presumably. So, that issue

When the towers were first built, one of the design questions was whether or not they could survive being hit by a 747 — on accident, presumably. So, that issue was taken into consideration. At the time of the attack, more modern aircraft were used, which had much thinner skins and were much more lightly constructed. Which means that they got much more shredded by the building construction as they passed through, and which also helped take off a lot more of the fire insulation from the trusses in the building.

542458 5y ago
The 747s simulated were also near-empty and flying slow, as the assumption was an accidental collision from an airplane lost in fog trying to land. They never simulated one nearly full of fuel running full-tilt.
- worik 5y ago
  And they sere simulations. Reality bites
- hunter-gatherer 5y ago
  Interesting. Do you have a reference by chance? I had no idea such simulations were run but in curious to learn more about it.
  - deadmutex 5y ago
    https://youtu.be/4eE8d94qGPo?t=222 https://youtu.be/4eE8d94qGPo?t=222
atdrummond 5y ago
The two towers were designed to sustain an accidental hit by a 707 on a descent trajectory. They were instead purposely hit by much larger 747s and at a much higher cruising speed. This meant that the kinetic energy transfer was approximately 8x larger than expected. The 747s at the time of impact also held significantly more fuel (at least 100% more) than those utilised in the 707 attack model.
- O5vYtytb 5y ago
  they were not hit by 747s
  - archon810 5y ago
    The twin tower planes were: 767-200 767-223ER
  - atdrummond 5y ago
    Correct. Sorry, I had originally typed 767 and then in an edit swapped as everyone else said 747 and I thought perhaps I was having some sort of Mandela Effect going on. The size and speed differential holds true - a cruising speed extended-range 767 is much faster and larger than the equivalent, landing-approach 707 the building was “rated” for.
pathseeker 5y ago
>When the towers were first built, one of the design questions was whether or not they could survive being hit by a 747 no, it was a 707 https://www.youtube.com/watch?v=4eE8d94qGPo&t=232s https://www.youtube.com/watch?v=4eE8d94qGPo&t=232s

542458 5y ago

The 747s simulated were also near-empty and flying slow, as the assumption was an accidental collision from an airplane lost in fog trying to land. They never simulated one nearly full of fuel running full-tilt.

worik 5y ago
And they sere simulations. Reality bites
hunter-gatherer 5y ago
Interesting. Do you have a reference by chance? I had no idea such simulations were run but in curious to learn more about it.
- deadmutex 5y ago
  https://youtu.be/4eE8d94qGPo?t=222 https://youtu.be/4eE8d94qGPo?t=222

atdrummond 5y ago

The two towers were designed to sustain an accidental hit by a 707 on a descent trajectory. They were instead purposely hit by much larger 747s and at a much higher cruising speed. This meant that the kinetic energy transfer was approximately 8x larger than expected. The 747s at the time of impact also held significantly more fuel (at least 100% more) than those utilised in the 707 attack model.

O5vYtytb 5y ago
they were not hit by 747s
- archon810 5y ago
  The twin tower planes were: 767-200 767-223ER
- atdrummond 5y ago
  Correct. Sorry, I had originally typed 767 and then in an edit swapped as everyone else said 747 and I thought perhaps I was having some sort of Mandela Effect going on. The size and speed differential holds true - a cruising speed extended-range 767 is much faster and larger than the equivalent, landing-approach 707 the building was “rated” for.

pathseeker 5y ago

>When the towers were first built, one of the design questions was whether or not they could survive being hit by a 747 no, it was a 707 https://www.youtube.com/watch?v=4eE8d94qGPo&t=232s https://www.youtube.com/watch?v=4eE8d94qGPo&t=232s