When I was a lowly pipeline observer, the stick wagglers I used to fly with always used to roll the throttle back to ground idle to check for a needle split before coming back to 100% again. Is this a mandatory part of the preflight on a Jetranger or something these guys chose to do just out of good practice? Were these checks done before the flights where the above documented failures have occurred? Would it have picked up on it or has the failure occurred between the needle split check and the incident?
Scary stuff indeed!