Just one post from busz that has anything to offer on what looks increasingly like a stall.
Pilots,when flying an approach,can either leave the AT in "ARM" mode(min speed reversion assured automatically) or disengage it altogether.If it was disengaged,then the pilot becomes responsible for ensuring speed remains above 1.3Vs.
Call-outs are made by the PM at the OM/1000 Radalt and 500 radalt to ensure that speed,profile and descent rate remain within limits.If the PF elects to "go visual" these calls may be omitted,although usually a 500' call will remain in case of incapacitation.Distraction and/or complacency can also lead to these vital calls being omitted.
Dual flame-out?Possibly but then we should really be looking at a picture of a 737 in a field without its back broken.The wreckage doesnt fit the dual-flameout.
Very early to speculate I know.Apologies.