Although principally what John says is correct and the complete flight path from autopilot disconnect to the crash may not be realistically simulated as it hasn't been tried out this particular situation should be more or less correctly replicated. Since the sequence can be visualised as first engine fail the autopilot holding with reduced speed at limit thrust then second engine fail autopilot quitting then the descent. It is closer to Dual engine failure which is a practiced manoeuvre in the SIMs.