A lot of them are designed to explode before hitting the target for maximum damage.
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.
The fact that there was a fire long after the impact shows the fuel was not burnt in the crash. Fuel hung around long enough to still be burning at least several seconds afterwards, long after the crater was formed. That is why it wasn't a missile. Missiles use high explosives (propellants and warheads) which burn up all at once to generally leave a non-burning crater.
Some back-of-napkin math yields a crater depth of a little under a meter ... which is in the ballpark of images.
aircraft (1.5m radius cylinder x 18m long) at 6700kg = 51.54 kg/m3 aircraft density... over ~1,500kg/m3 average soil density x aircraft 18m length = 0.63m
=.63m / 2-foot penetration below ground level... which is what the pictures show.
Soil is dense. Aircraft are marshmallows compared to soil.
In the explosive sense, I agree. Depending on how much fuel they had, it could’ve been a decent percentage of the aircraft’s weight, though.
But yes, that's a lot of kinetic mass dead-stopping on a hard surface and 1 to 2 kiloliters of jet fuel.
At 30fps, I make that somewhere in the region of 1000mph.
(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.)
Let's not argue over the approximate nature of "1000mph" given the measurement constraints.
I think it's pretty much a mercy that no-one aboard would have felt a thing in the last couple of dozen milliseconds.
https://www.pprune.org/accidents-close-calls/674728-lear-60-...
Sad story in this case. The cockpit audio was quite chilling.
I don't intend to listen to the audio. Second-hand, it sounds as though they did absolutely everything they could after hitting the cell, and the only way to have avoided this whole situation was "Don't fly that route that day."
... a problem that, in general, we see more often in private-jet and single-engine aviation than commercial-carrier aviation. Far more incentives to make a really, really bad call... And when the bad call happens, the Venn diagram of victims and responsible parties tends to have a lot more overlap, so there's, practically speaking, fewer consequences to discourage such bad decisionmaking in the future (can't meaningfully punish the dead, and the dead can't learn from experience what a bad call "smells" like on the lead-up to it).
Another possibility is flutter. I read overspeed and icing mentioned by a pilot in the transcript. Therefore I think of those two elements conspiring in an edge case resulting in forces exceeding design limits, something broke, and made recovery impossible.
But anyway, the investigation will likely answer these questions.
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.
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"?
The crater shows the road was destroyed. Aircraft skins are much thinner and less robust than road coverings.
You can see the macroscopic deformation fail to transit the body of the impacting object with enough speed to make gross deformation happen as it collides. The front of the rocket body is literally turning to a vapor at the impact site, and the tail assembly is 100% fine.
The vertical speed of the plane alone at last reported speed indication exceeds the speed of neuron transmission along myelated nerve tissue. This impact event is mechanically impossible to feel.
Well, just looking at the article, I see trees, which tend to slow things down and can cause a plane to break up.
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."
Highly recommend anyone reading to not make the same mistake
In every thread on this not a single person I have expressed anything other than regret for having heard it
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)
Once the aircraft entered the conditions inside the storm, between the turbulence, icing, and up/down drafts it was likely an unrecoverable event.
IANAP but the mention of precipitation points to conditions that could overwhelm anti-icing systems, which the Learjet was equipped with.
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.
35,000 to 37,000 feet, combined with turbulence from the weather, means this could come into play. We still don't know and may not know for some time, especially given the severity of the impact and what may or may not have survived. But you can't rule it out.
[1]: https://aviationweek.com/business-aviation/learning-test-pil...
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.
Whatever the cause, it seems like climbing to avoid turbulence in or near thunderstorm conditions when the pilot knows there is ice already was probably unwise. A more prudent course was probably to divert around it and/or to descend to de-ice the plane. If so, would this rise to the level of pilot error? I don't know but maybe.
Staying away from thunderstorms is a good rule of thumb no matter the aircraft and crew capabilities. Severe turbulence is expected within 20 miles of the visible portion of a severe thunderstorm.
AIM 7-1-26 paragraph c is in all caps:
NO FLIGHT PATH THROUGH AN AREA OF STRONG OR VERY STRONG RADAR ECHOES SEPARATED BY 20-30 MILES OR LESS MAY BE CONSIDERED FREE OF SEVERE TURBULENCE.
AIM 7-1-27 can be summarized as stay the fuck away from thunderstorms. This entire section is dedicated to avoidance.
https://www.faa.gov/air_traffic/publications/atpubs/aim_html...