henra
Hmmmm, an engine problem (unless complete double engine failure with altitude hold engaged an no intervention until the stall - but how likely would this be???) should not lead to a loss of 110kts within one Minute of straight and level flight!? And all this in day VMC. That said, a propeller going into Beta/Ground idle at 200 kts could potentially cause quite some drastic effects.
The latter is one of the few reasons I can think of that would produce such a rapid deceleration in level flight.