Salute!
Gotta go with "SLOW" and "A^2. No pitot/static covers left on. The problem was there even before the flight before.
Pitot/static problem? Yep.
Trim system function with bad air data? Yep, or a strong maybe..
Mechanical failure leading to an extreme dive to impact? Don't know
++++++++++++++++++++++++
News media now claims the main fuselage has been detected, and the "pinger" or tone of one recording device has also been detected.
Gums sends.......