Lone,
Point is the 97 is single engine so "an" engine (implies more than one) rolling back is not applicable. Very possible it puked the engine. Question remains with exception of a
PR flight why was the gear up (as "confirmed" by articles) when hovering/low speed over a hard surface? They obviously were not doing HV/auto testing. I guess it is always possible they landed after forgetting to lower the gear, but not likely. On the 609 we had a special rig we could land on should the gear fail to extend, do not see similar here.