It always saddens the whole world to hear or to witness air plane crashes. Our hearts go to China Eastern Airline MU5735 immediate family, company workers and friends of the victims. Here's what some friends of mine thinks.
Setting aside act of terrorism or foul play, the case of China Eastern Airline crash is almost similar to XL Airways Flight 888 (acceptance flight for an Airbus A320 on 27 November 2008), the plane stalled and the captain increased power while pushing his side stick forward to bring the nose down - a maneuver to prevent stalling but it doesn't work. The plane continues to pitch up until it loses lift and falls from the sky - crashed into the Mediterranean sea - believed to be in vertical attitude just like China Eastern Airlines
Based on the investigators finding :
Computer simulations help to analyze flight 888's final flight check. It appeared that the Captain deliberately slows his plane down for the test, but the computer lets the speed drop too far. Below the minimum needed to keep the plane in flight. There was a warning on the cockpit flight display (Use Man Pitch Trim) - moments before the crash. It's to alert the pilots that the flight computer is no longer helping to fly the plane.
The plane has been switched to full manual mode. The warning comes on when the plane's computer gets conflicting information.
The sensors are telling the computer the plane is flying level but other onboard sensors are relaying its' extreme nose up attitude. One of these readings must be wrong. Perhaps in the chaos, the pilots didn't see the warning.
In manual mode, by increasing power while pushing his side stick forward to bring the nose down is not enough where they also need to adjust the trim wheel for a more dramatic change of pitch.
Note :
The abovementioned was only a test flight (acceptance flight) using Airbus A320 and it was being operated by the best pilots just like China Eastern Airline. A320 is different than the China Eastern Airline where it involved Boeing 737 800. (Both A320 and B737 800 have a good reputation of a long safety-track record)
However, we still have to wait for the recovery of the "black box" and data analysis captured by Flightradar24 in order to know the real findings.