Winch hook missing
Interesting that the winch hook is missing, I am assuming that the crew were possibly carrying out winching evolutions between 17:50 and 18:20 looking at the the altitude and speed profiles. If the hoist was not isolated correctly on departure from the the hover, the aircraft then climbs and accelerates to 1000' and 80-100kts. Purely on assumption, if the winch were to have reeled out uncommanded due to a faulty pendant or faulty control circuit; with no weight on the hook at 80-100kts..........where is the winch cable going?
Maybe just pure speculation, but if the un-weighted cable were to have found itself around the rotor head/ tail rotor, it wouldn't be pretty.