This also might explain reports that the airplane went over 40,000 ft where there is less oxygen for the fire.
The climb to 40,000+ feet points to two things, and two things only; either to kill the passengers or extinguish a fire.. ACARS could’ve been turned off without ever having to turn the knob off.. It could’ve happened electrically due to fire. If the wires are compromised it doesn’t matter what position the switches or knobs are in. The electrical system could’ve also gone haywire and communications cut right after the ‘alright, good night’ message.
What better explains it is that the pilot was curious to see if he could hand fly the airplane at 40,000 because it isn’t supposed to be doable. hence his flight simulator. He was curious and lost the bet.