The million-dollar question now is how it managed to recover after plummeting 2/3 its altitude, only to do so again shortly after? That shows that it was still operable and could aviate, and opens up many more questions.
I'm not sure if briefly levelling off for about 30 seconds is proof that the plane was "operable and could aviate". It feels more like the pilots briefly got some control back, before the situation worsened again.
Of course really trying to speculate at this early stage on limited data is pointless. We really need to wait for some hard information to come out of the crash investigation.
This is because flightradar24 measures ground speed. A rock dropped from a building has a ground speed of zero. The apparent recovery was due to the fact that the aerodynamics of a 737 in a nosedive force it to pitch up somewhat. But the pilot probably pushed it back down.
Possibly explosive decompression then they go way too fast on the emergency descent so pulling out of the dive caused structural failure leading to the crash.
Does a complete loss of control result in a nose dive? I imagined that planes would be aerodynamic enough to crash at something far closer to horizontal than 90 degrees down.
It depends on exactly what has happened to cause a lack of control. Essentially all fixed-wing aircraft other than high-performance military fighter jets are built to be aerodynamically stable: if you do nothing, they go in a straight line and if they are in an established turn, they tend to continue in that turn. There are plenty of examples of "famous" not-as-bad-as-they-could-have-been crashes where control was effected unconventionally in aircraft made otherwise uncontrollable by mechanical failure -- for example, using throttle control to land aircraft experiencing their phugoid nose up / nose down inherent dynamic stability mode [1, 2].
Full blown nose down is rare unless controlled flight into terrain. The obvious armchair speculation I would make here is that a total separation of the tailplane / stabilator or empennage of the aircraft could cause something approximating that -- the tailplane provides negative lift and without it the aircraft would pitch up until it stalled, and then a series of exponentially growing oscillations would likewise result.
It's far better to wait for the NTSB accident report and deliver sympathy and aid to those affected, however -- we don't have the facts and I am sure that they will be determined in the fullness of time.
I am not going to speculate about this crash, but the claim made here about stability is missing one very important fact: just about every airframe exhibits spiral instability and will eventually undergo spiral divergence unless controlled by a pilot or automatic system. This results in an airplane descending in a steeply nose-down spiral even though it is trimmed for level flight. As a result, most spatial-disorientation crashes end in a steep nose-down impact with the surface, as in the case of JFK jr.
Such accidents are way too common - Informally, I get the impression that there may be up to one a month in the US alone - but they are rare in airline operations and I am not suggesting that this is likely here.
This is true -- and I forgot to mention it (although I was perhaps obliquely alluding to such things with the CIFT comment). My brain meant the more the conventional dutch roll / longitudinal static stability concerns that are perhaps more actively considered in airframe design and aerodynamics. Thank you for pointing this out.
>On 4 July 1989, a pilotless MiG-23 jet fighter of the Soviet Air Forces crashed into a house in Kortrijk, Belgium, killing one person. The pilot had ejected over an hour earlier near Kołobrzeg, Poland, after experiencing technical problems, but the aircraft continued flying for around 900 km (600 mi) before running out of fuel and descending into the ground. [Where it killed a Belgian citizen on impact.]
> Full blown nose down is rare unless controlled flight into terrain.
I agree with you that full nose down attitude is rare in accidents. It is rare even in controlled flight into terrain. The typical CFIT scenario is one where the airplane is flying straight or close to in bad visibility and they hit the side of a hill or mountain because of a navigational error.
>It's far better to wait for the NTSB accident report...
You seem to be measuring "better" in terms of "not saying things that may become obviously false as more information becomes available with time".
Many internet commenters measure better in terms of how many internet virtue points they get, hence all the completely baseless speculation you get on literally any developing news story. I'm sure those people disagree with my assessment but their actions tell a different story.
I enjoy 'completely baseless speculation'. To me, it's especially interesting regarding subjects i know nothing about.
I understand plane enquires may take years, so its always interesting to see who was most correct, as well as the more immediate satisfaction of another speculator negating a proposition, and proposing another.
It's hard to measure an accident rate for a plane that has never crashed. And that in turn is mostly because they're all relatively new and rare and thus haven't accumulated even a fraction of the working hours of something like the 737NG, which is the most popular passenger jet ever made.
I'm not saying Airbus is inferior. I'm saying: if you won't get on an NG, what will you get on? There's no data to indicate that modern Airbus models are unsafe, but there's also no data to indicate that an NG isn't. All Boeing planes didn't suddenly become the MAX after 2019.
I'd be more worried about when/where/who is flying my plane than anything else.
It's completely meaningless as a counter of the point that corporate culture at Boeing has changed for the worse from the company that built the 7x7 series to today
I am with you with respect to newer Boeings, but it is nearly impossible to know in advance, which I see as a major issue. You could book thinking one thing and the airline swaps in something else before the flight.
I think if passengers could make these decisions that would filter into the decision making of airlines which would then hit the manufacturers in terms of orders.
The phrase at the start of the Jet age used to be "If It Ain’t Boeing – I Ain’t Going". Boeing was a reliable company that built planes.
That culture has been missing for a couple of decades, and the rot takes a long time to set in. It's not about specific planes or specific technologies, it's a shift from Boeing being a cmopnay that survived by making a high quality product which happened to make some money, to one that needs to make ever increasing money and happens to make products
It's not a Max, but it's extremely clear that the 737 is an outdated aircraft family. It's not directly relevant to this crash, probably, but it makes me a bit sad that we can't find our way out of this kind of local minimum.
and some cars are fairly old too (pick any long-running somewhat-consistent model for a fair analogy), but they've changed since inception to be safer, more efficient, more reliable, etc. (minus the max, that's shoehorning something new to an old family)
Simply saying the family is old does not do it justice. It's possible for some "old" setup to continue to be effective even if other things change.
GP didn't say it was. They said the Max was just a symptom of a larger problem.
After the Max crashes, there were reports of sloppy production in Boeing factories. If those were correct, it's conceivable that other planes would be affected.
No 737-800 is not max. It's just one of the longer NGs.
There's an even longer -900 too.
So whatever happened, it's safe to say it was not MCAS. I wonder what did happen though.. But no doubt they authorities will find this out in due course.
Some posted videos basically show it going almost vertically down :( RIP.
Making a reference to whatever related subject has a lot of mindshare is a pretty common format for low effort comments around here. It's just HN's high brow version of making an equally low effort quip about the front falling off.
It clearly gets a positive reception sufficiently more often than a negative one or people wouldn't do it.
https://twitter.com/flightradar24/status/1505863117343014916