Thanks, Jack - that was the point I was seeking to clarify. With this hidden problem with the torque, it just seemed to me that this preponderance to roll sharply to left with certain flight settings could have happened at any time, regardless of the weather. Would that be correct?
Basically in the latter stages of the final approach to 17 the Commander (PNF) took control of the Power Levers - Which was acknowledged by the Co-pilot (PF). This is an unusual move, as normally the PF handles both flight and engine controls in a coordinated manner to achieve the required flight path - When the PNF took control of the Power Levers they were subsequently retarded below Flight Idle - an action which would have been unexpected by the PF.
Recorded data showed that the No. 1 engine retarded to -9% torque in beta range, whilst the No. 2 engine stayed at 0%.
Then to quote the AAIU,
''This thrust asymmetry was coincident with the aircraft commencing a roll to the left (maximum recorded value of 40 degrees bank). It is possible that the PF may have made a control wheel input to the right in response to the unanticipated left roll. However, without FDR parameters of control wheel or control surface position the Investigation could not determine if such an input was made. The subsequent application of power to commence the go-around, at approximately 100 feet, coincided with the commencement of a rapid roll to the right and loss of control. The roll continued through the vertical, the right wingtip struck the runway and the aircraft inverted.''
And again to quote the AAIU,
''A torque split between the powerplants, caused by a defective Pt2/Tt2 sensor, became significant when the power levers were retarded below Flight Idle and the No. 1 powerplant entered negative torque regime. Subsequently, when the power levers were rapidly advanced during the attempted go-around, this probably further contributed to the roll behaviour as recorded on the FDR.''
So basically to answer you question Sunnyjohn, yes this could have happened in another situation - however as with all accidents its a number of factors which line up together to cause it and as the AAIU have provided 54 findings, a probable cause, 9 contributing factors and 11 safety recommendations to show this.
Again to Big Pistons Forever, trying to pin this down to a single factor is both nonsensical and dangerous - We need to learn from
all the factors of which descending below minima is one.