“Does this mean they lost engine power and were trying to glide in? Asking the FR pilots.”
The props feathered so they had no thrust.
Think there was speculation among pilots that the crash followed a stall due to the turn into final approach being too tight. So it wasn’t the engines cutting out that caused the crash in their opinion, it was the low air speed that caused the stall (that caused the crash).
To my knowledge props can only be feathered by deliberate human action with dedicated controls for feathering. From the brief video it appeared left wing stalled and plane went into spin. Would indicate plane just going too slow on approach.