Aircraft stalls and/or upsets often lead to engine stalls and surges in the same event. Thus the proverbial eye witness reports of explosion and fire from the engines before the plane crashed.
Stall/surrge is typically only indicative of a short time recoverable power loss (1-2 sec) and usually not significant to the aircrafts performance and typically confirmed by eye witness accounts of a brief flash of flame out both the tailpipe and the inlet often associated with a loud noise if at high power.
However non-recoverable stall/surging equates to significant and/or permanent power loss for the engines involved. Eye witness accounts of such are continuous flame visible in the tailpipe.
Flameout is a loss of flame in the engine and does not correlate with witness accounts of visible flame associated with the engine.
the above is a primer for interpreting eye witness reports