Private Jet plane crashes in Florida

(cbc.ca)

36 points | by hmokiguess 1 hour ago

11 comments

  • haunter 1 hour ago
    It looked like a missile https://streamable.com/lg0on2
    • mrweasel 1 hour ago
      The sound is just crazy and the images of the crash site seems somehow worse than what we've seen from e.g. Ukraine when a missile miss and slams into the ground.
      • 233mhz 42 minutes ago
        > when a missile miss and slams into the ground.

        A lot of them are designed to explode before hitting the target for maximum damage.

      • shadowgovt 52 minutes ago
        A fully-fueled private jet is an inefficient missile, but it exceeds the raw chemical energy of most in-theater single-target tactical missiles (although the energy conversion is far less precise and efficient).

        But yes, that's a lot of kinetic mass dead-stopping on a hard surface and 1 to 2 kiloliters of jet fuel.

        • dist-epoch 4 minutes ago
          Technically called a wet explosion. Fuel deflagration, not explosive detonation.
      • tokai 31 minutes ago
        The private jet carries up to 3.5 tons of fuel and weighs over 10 tons at take off. A Kalibr cruise missile is maximum 500kg of explosives and the heaviest variant is 2.3 tons over all.

        Its not surprising at all that the jet makes a huge hole in the ground. Jet fuel is more energetic than RDX, while converting that energy slower. So both the chemical and kinetic energy is much higher with the jet then with a russian cruise missile. If anything the crater is surprisingly small.

    • ErroneousBosh 47 minutes ago
      Learjet 60 is about 18 metres long. In one frame it's a little above the ground, in the next it's gone up to about halfway between the cockpit glass and the wing roots, and in the next it's gone.

      At 30fps, I make that somewhere in the region of 1000mph.

      • mkl 32 minutes ago
        CBC article says vertical speed was 30,000 feet per minute, which is 550km/h or 150m/s.
        • dist-epoch 4 minutes ago
          it was also moving forward, not just downward.
      • 00deadbeef 39 minutes ago
        The audio (don’t listen to it) has the pilot reporting the descent speed as 22,000 feet/min
        • ErroneousBosh 33 minutes ago
          I'm not planning on listening to it. I would expect that happened long before it hit the ground.
          • 00deadbeef 24 minutes ago
            I’m not going to listen again to verify this but it felt like 20 seconds before they hit. The recording was only about a minute long.
      • OJFord 34 minutes ago
        Last transmission was 22k feet/second, which is 15k mph.

        (I thought ATC's cool as a cucumber 'altitude your discretion' was 'interesting' – presumably a formality they need to offer to clear the aircraft, since clearly no discretion was involved.)

        • 00deadbeef 22 minutes ago
          No it was feet per minute. 22,000 feet/second is almost orbital velocity.
          • OJFord 5 minutes ago
            Oops, thanks. Not familiar units for me.
      • dnel 35 minutes ago
        there is dashcam footage from further away that gives a better indication of speed. It was fast but not supersonic.
  • andyjohnson0 49 minutes ago
    There's a thread on pprune about this incident. The usual mix of informed and less-informed speculation.

    https://www.pprune.org/accidents-close-calls/674728-lear-60-...

  • robot_jesus 1 hour ago
    It’s amazing to me that this post already feels quite old. But then I realized it only happened yesterday. I just feel that way because in today’s world we have seven different dashcam or security camera video feeds popping up on Reddit or X or whatever within minutes of a news event like this.

    Sad story in this case. The cockpit audio was quite chilling.

    • p_l 1 hour ago
      It's not even cockpit audio, it's just from ATC radio : - \
  • christophilus 1 hour ago
    Don’t just crash. Was full throttle into the ground, by the looks of it.
    • ajross 31 minutes ago
      No, throttle was surely idle. The plane was just flying vertically. In a dive, you have a 1:1 thrust/weight ratio and can go extremely fast. The pilot reported an overspeed warning on the audio (which people should not listen to if they're sensitive).

      My gut says this is a sudden icing incident. Folks are pointing out that they appear to have flown straight into the center of a cell at altitude. A developing thunderstorm is MUCH warmer than the surrounding air, because the water condensing out of the rising/cooling mass buffers the temperature (due to heat of fusion). It can even be supersaturated ("higher than 100% humidity") if this happens fast enough. The water vapor is just desperate for a nucleation site to condense on.

      So you have a situation where a metal jet body that is maybe 30C colder than the medium suddenly flies through this soup. It can ice over in seconds to minutes, and the plane ends up with bricks for wings and much more weight than it was designed for, and simply can't stay in the air. Then it dives inexorably.

    • Xenoamorphous 45 minutes ago
      Question from someone who knows nothing about aviation, is it possible that the pilot did that knowing they were doomed?
      • throwup238 38 minutes ago
        It’s easy to get disoriented and accidentally accelerate into the ground, yes, (which is basically the procedure in a stall to get lift back anyway) but based on the ATC recording they knew what was going on and just dropped out of the sky.
      • balderdash 18 minutes ago
        Anything is is possible, but Mach tuck may have been an issue [1], but it slo may have been actual flight controls.

        https://en.wikipedia.org/wiki/Mach_tuck

      • jetrink 32 minutes ago
        The pilots were trying to save the plane up until the last moments. They declared an overspeed condition soon after they ran into trouble, so they were aware of it, but did not intentionally cause it.
    • shadowgovt 47 minutes ago
      Forward velocity is proportional to lift, assuming your lifting surfaces still work. If you're stalling, standard practice is to apply power and get the nose down so that gravity and engine thrust are working in your favor to put air back under your wings.

      In this case though, it sounds like the icing was much worse than they thought and fatally compromised the aerodynamics of the wings, and then the overspeed would have torn at the wings and fuselage... In that circumstance, you're no longer flying a plane, you're riding a javelin.

      Training would generally still encourage the pilots to apply power; in the worst-case scenario (here), failing to apply power would not have made the crash survivably slower, so the sum total of best bad actions is still "Apply power and hope you're not in the worst-case scenario."

    • kzrdude 1 hour ago
      Reading what the pilot said is pretty harrowing. We know a lot from what the pilot already said over the radio (and maybe that's the best info we'll get, are there any remains left?)
      • nradov 1 hour ago
        Very little will be left considering the impact speed. Even if the aircraft was equipped with a flight data recorder (black box) then its structural limits were probably exceeded.
      • p_l 1 hour ago
        The speculated final velocity at time of impact greatly exceeded design parameters for black box survivability so...
      • giarc 1 hour ago
        You would never know a plane caused that crater since there was so little left. Hopefully it puts to bed the conspiracy theories of the plane that crashed into the pentagon. Doubt it though.
        • elorant 38 minutes ago
          Judging by what is circulating in Twitter today it mostly flared them up
      • embedding-shape 1 hour ago
        > is there any remains left

        If there is, seems they're deep under the ground as it nosedove straight into the ground and essentially disappeared, the crater showed almost no debris at all. People been guessing on reddit that everything just got "instantly pulverized" which I doubt somewhat, the shape of the frame is perfect for it shooting into the ground so I'm guessing they'll spend some weeks digging and eventually find the wreck.

        Edit: Since I can't respond to my children:

        > This kind of impact in fact has tendency to turn aircraft into powder

        How often? A similar crash that comes to mind is https://www.washingtonpost.com/transportation/2023/06/05/dc-... where they did recover actual bodies, even if the impact was near-vertical and seemingly faster than this case.

        What specific cases are you thinking about where everything "instantly pulverized"?

        • criddell 15 minutes ago
          Mythbusters did this with a sled going "only" 650 mph and I would call the result instantly (but not entirely) pulverized:

          https://youtu.be/aSVfYwdGSsQ?t=132

        • TheOtherHobbes 36 minutes ago
          https://x.com/Nalanda_index/status/2117064398166777927

          The crater shows the road was destroyed. Aircraft skins are much thinner and less robust than road coverings.

        • p_l 59 minutes ago
          This kind of impact in fact has tendency to turn aircraft into powder
        • DoneWithAllThat 51 minutes ago
          Er, no. You’re greatly underestimating or misunderstanding the forces involved here. “Instantly pulverized” barely even begins to describe it.
          • kzrdude 44 minutes ago
            In the video in the thread, it seems to go from fully extended airplane to pancake in about two frames, which is, again, harrowing, horrible.
            • TheOtherHobbes 33 minutes ago
              It's basically airframe to dust in three frames, so maybe a 1/20th of a second. The moment of impact would have been mercifully quick.
        • wickedsight 34 minutes ago
          > A similar crash that comes to mind ... where they did recover actual bodies, even if the impact was near-vertical and seemingly faster than this case.

          Well, just looking at the article, I see trees, which tend to slow things down and can cause a plane to break up.

  • meowcat 20 minutes ago
    I don't want to be a naysayer, but what is this doing on HN?
  • eej71 1 hour ago
    I regret listening to the audio. There is nothing gained by hearing it.
    • HiroProtagonist 1 hour ago
      It's a tough listen and I don't begrudge your regret listening to it, however I think the pilot did a remarkable job of communication information about speed and bank angle right to the end which will indeed help this investigation and hopefully prevent future incidents.
      • Suzuran 16 minutes ago
        The nice thing about all the tapes and recorders is that when you know you're completely fucked, you can be damn near assured that the last things you choose to say will be preserved. Whether you make it a last message to your family, or as many technical details as you can throw out that might help the investigation and keep someone else from dying the same way. In a way, documenting as much as you can of your impending death becomes your final task.
    • hbcdbff 32 minutes ago
      I always ignore warnings like this and am usually never affected by such audio but I feel psychologically scarred by it

      Highly recommend anyone reading to not make the same mistake

    • goldcd 53 minutes ago
      Yep - some people are being paid to listen to that, but I'm not.
  • jmyeet 1 hour ago
    It's unclear exactly what happened but I've heard some aviation experts talk about this and there are already some leading theories, which come down to two factors:

    1. The so-called coffin corner [1] where the minimum safe speed for aerodynamic lift and the speed where the plane will stall narrows to a dangerously narrow window. This is caused in part because the speed of sound decreases at high altitude. Turbulence can throw you out of this window; and

    2. It seems likely that control was lost because of ice. In released ATC recordings (which are awful to listen to, be warned) the pilot mentions ice. This is likely because of the bad weather over south Florida right now.

    The pilot requested a new flight path and I believe tried to ascend from 35,000 feet to 37,000 feet and ended up in a spiral, banked at ~60 degrees, descending at ~30,000 feet per minute, crashing into the ground.

    I'm not a pilot but I suspect there will be some element of this that is pilot error or at least could've been avoided and/or mitigated by an experienced pilot.

    [1]: https://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)

    • cmiles8 50 minutes ago
      There will be many questions on why the pilot flew into the tops of what (at least on radar) appeared as a small-ish localized cell at that altitude. Vertical cloud development at those altitudes is a clear sign that whatever is inside is not going to be pretty.

      Once the aircraft entered the conditions inside the storm, between the turbulence, icing, and up/down drafts it was likely an unrecoverable event.

      • altmanaltman 37 minutes ago
        yeah but they could/would definitely break during the descent so you can't know if that was the cause or the effect
    • Zigurd 21 minutes ago
      Icing was mentioned early in the ATC audio, then a request to increase altitude, then a comment that they encountered precipitation, implying the icing could get worse.

      IANAP but the mention of precipitation points to conditions that could overwhelm anti-icing systems, which the Learjet was equipped with.

    • sandworm101 54 minutes ago
      It wasn't coffin corner. This was a Lear at reasonable altitudes, not a U2 at the edge of space. The death spiral suggest a loss of control authority. It is conceivable that one wing severely iced to the point of unrecoverable asymmetric lift but I think it was something more the icing. It might have lost part of its wing, or the controls on one wing locked into an unrecoverable position.

      In the pictures, the flaps appear present but not extended. If they had been extended they would have ripped away at that speed. And they would not have been able to lower them after the overspeed began. I think the answer is in the control system. One or more control surfaces were doing something other than commanded.

      Some images seem to indicate a loss/absence of the horizontal stabilizer, but it is hard to tell AI from real these days.

    • CPLX 34 minutes ago
      That doesn't match what I'm seeing in the online discussions. I think most people who have a basic understanding of aviation or have been part of it would immediately see this as what happens when you fly a Learjet directly into a thunderstorm. The likely question is whether the first cause of loss of control was ice or something aerodynamic, like pushing the nose down in an updraft, causing the horizontal stabilizer to rip off.

      In contrast, the coffin corner doesn't really have anything to do with this the plane would have been operating at standard enroute altitudes and speeds.

      For context, I am in fact a pilot. I've read a little about what people are saying about this accident, but I've absolutely no new information or unique insight whatsoever.

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