• Onomatopoeia@lemmy.cafe
    link
    fedilink
    arrow-up
    16
    ·
    2 days ago
    1. It would have to be at least 2000 ft up, otherwise you wont have time for a chute to open

    2. Related to 1 - flying is about altitude, which translates to how much time you have. Higher you are, the more time you have to do something. I suspect there was very little time between the failure and impact, leading to…

    3. If there was a mid-air failure (say a wing collapsed) the g-forces caused by the plane suddenly falling to one side would effectively pin everyone to the opposite side. Acceleration due to gravity is a bitch, and combined with the suddenness causing confusion, they didn’t stand a chance.

    4. Back to time - a common altitude for jumping is 10k feet (somewhere over 5k at least). A plane falling from loss of a wing is going to drop like a stone (lift is gone), probably at 80-120 mph. That will close the distance to ground very quickly - and I suspect they hadn’t made it anywhere close to 10k before the failure since an observer remarked about seeing a failure. You could see it at 10k, but it wouldn’t be easy. At 5k it’s pretty easy to watch and see the plane’s shape.

    Source: was a skydiver at one time.

    • x00z@lemmy.world
      link
      fedilink
      arrow-up
      8
      ·
      2 days ago
      • 2000 feet = 610 meters
      • 10k feet = 3km
      • 5k feet = 1.5km
      • 80-120 mph = 130-190 km/h
    • krashmo@lemmy.world
      link
      fedilink
      arrow-up
      2
      ·
      2 days ago

      I’m not saying you’re wrong but why are you claiming that it takes 2000 feet for a chute to open? People jump off of buildings that are shorter than that all the time. Are they using different equipment or techniques than people who jump from planes?

      • Onomatopoeia@lemmy.cafe
        link
        fedilink
        arrow-up
        4
        ·
        edit-2
        1 day ago

        I believe Base jumping uses different chutes (smaller) or at least a different design for low-velocity opening. They also hold a drogue chute in the hand for release - conventional chutes rely on airflow past the bag to pull the drogue and chute out.

        As a skydiver there’s a general rule that 5k feet is decision altitude - if you don’t have a good chute then (tangled, not fully deployed, etc) you need to decide NOW if you’re going reserve, because it takes time (altitude) to cut away and release your reserve - and hopefully this gets done before you hit 2k.

        And there’s kind of a general rule to not fuck about under 2k feet, because you have no recovery time.

        Also, BASE jumpers are nuts! Haha

        • Count042@lemmy.ml
          link
          fedilink
          arrow-up
          2
          ·
          edit-2
          1 day ago

          Decision altitude for an a license is 2500 feet. Hell, most DZ’s consider it pulling high if you’re over 4000 ft, and require you to exit the plane last, if there are no wing suitters.

          Reserved parachutes are TSO’d to open in 300 ft and are generally seven cells rather than the standard 9 cells for main canopies.

          One of the jump requirements for your a license is to do a hop n pop (where you jump and deploy immediately) at 3500 to simulate an emergency.

          Now, I don’t know about France as different countries have different rules, but in America you have to be buckled in with the door closed until 1000 ft.

          Source: got my a license last year, have fifty jumps, and have jumped out of a jet (a DC-9), and a Huey.

          If the plane is having issues under a 1000 ft, it’s going to be hard to get unbuckled, get the door open, and jump out. And even If the reserve is supposed to be fully open in 300 ft, I wouldn’t want to jump anything below 1500, and that only of I was certain the plane was going down and I’d be stable on exit.