It turns out a pilot error, but why?
According to the report, it was allowed to reduce the altitude to 17,000 feet, but the pilot initially set the altitude of 15,000 feet on the AP, and then set the altitude to 14,000 feet.
Everything, including engines and anti-icing systems, worked fine, and a technical problem was not noticed.
The pilot at 9:31:14 received a warning from GPWS.
From another forum:
Interesting decision to re-engage the autopilot following a stall. Not necessarily a turning point in the sequence of events. I'm assuming the momentum of 67% from that point on? I believe around low 70's is a normal cruise power for those altitudes in that aircraft. Certainly reads like there was a major breakdown in situational awareness in the flight deck.
Ignoring a GPWS for 12 seconds is puzzling. Language barrier? Startle effect? Poor training?
Final (?) report, but not yet translated into English ...
http://www.mizanonline.com/files/fa/...555079_507.pdf