No speculation here to a cause, but merely replies to a couple of queries in prior posts. Condolences to the pilot's families and greater Air North family.
Props have been known to do worse then windmill.....
Reverse would render it pretty unflyable
It wouldn't be the first Bras to pull Beta inflight.
ASN Aircraft accident Embraer 120RT Brasilia N270AS Brunswick, GABrunswick-Glynco Jetport, GA (BQK)
An Airworthiness Directive was issued very quickly after the Atlantic Southeast accident and I have never heard of anything else similar since as far as the Brasillia and PW100 series is concerned.
I don't know what engines the Braz has. With the PW12x on the DHC8 there is nothing (apart from the triggers, which are not locked out in flight) to prevent you from retarding the power levers below the flight idle detent.
The Bras as a mechanical gate on the pedestal, as well as a lock out solenoid to prevent PLA below flight idle once weight off wheels. The solenoids can be locked out be tripping a CB.