A question for the techies,: the props were in "almost feathered positon" , due to the impact ?
Could be.
Or it could be they were set that way (either by the pilots, or an automated NTS system) to avoid "negative torque."
Very roughly and oversimplified, an analog to "engine braking" in a piston engine - the prop (or vehicle wheels) driving the engine, instead the other 'way around, at low power/throttle settings and higher airspeeds. The reduction gearing in TP's (which converts turbine rpms of 10000-20000 to prop revs of 1500-2000) "doesn't like" being driven front-to-back (negative torque).
Moving the pitch of the prop blades towards 90° (feathered) reduces how much backwards torque is applied to the engine shafts and reduction gears, from the prop spinning in a high-speed slipstream like a child's pinwheel in the breeze.
https://skybrary.aero/articles/negat...ing-nts-system
Negative torque can be produced by
any low-power condition in the turbine -
sometimes an actual engine failure, but also simply low throttle/power-lever settings. And the specific effects and limits can be different for different specific engine types.
Bottom line - there are limits to how much power can be reduced in a TP engine if one is trying to get down quickly at a high airspeed, by reducing power (fuel flow). The reason TPs have "flight idle" and "ground idle" settings.