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.
[1] https://en.wikipedia.org/wiki/United_Airlines_Flight_232 [2] https://en.wikipedia.org/wiki/2003_Baghdad_DHL_attempted_sho...
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.
Recent, computer controlled jets, rather. Older jets were aerodynamically stable, probably because otherwise they would have been very fatiguing to fly. There are at least two well known instances of pilots ejecting from fighter jets that then recovered to normal flight: https://en.wikipedia.org/wiki/Cornfield_Bomber and https://en.wikipedia.org/wiki/1989_Belgium_MiG-23_crash
>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.]
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.
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.
