I distinctly remember talking to an old Provincial and Douglas mate "Gangrene" as he was known and yes Provincial did operate a BN3 Trislander that came to an end apparently on takeoff in the Madang Province somewhere.
It flew into a river at the end of the runway and a few locals died simply because they couldnt undo their seatbelts.So very sad.
The BN3 was ok to fly, a bit of a truck to wrestle with as it was heavy in ailerons as mentioned but it was slightly faster (135 kts) and carried a good load.
Great aircraft for coastal flying but we used to scare ourselves in the hills around the Western/Eastern Sepik Province occasionally doing the RPT run from Vanimo to Wewak and back and also around the Madang province (Aiome,Tep-Tep,Sangapi etc etc).
The thing that made me laugh was the rear vision mirror so you could see the rear engine and the red flashing light that told you of the failure of the number 2 (rear) engine.
The balancing trick walking along the spine of the aircraft roof to check the oil and grabbing the rear engine once you got there so you didnt fall brought back fond memories.
Great after a night on the SP!
Even burnt out the brake pads once or twice too!
A $hitbox.maybe.
A truck....yes.
Character building and a challenge to fly...............definitely!