Rr250 B17
There seems a Holden/Ford style comparison running hear about the -250 B17 engines compared to the PT6? There is no comparison, PT6s are different engines usually built for aeroplanes with higher power requirements. They are more expensive to buy and to run than the smaller (in size) RR250 range.
NB: the Nomad used the B17C rated at 420 HP whereas other similarly engined aircraft use much lower power ratings. If the 250 engine did have a reliability problem in the Nomad, it was more related to trying to take too much out of it than anything else. To my knowledge, there is no reliability issue on the RR250 range of engines other than that made up in the minds of PT6 advocates. The RR250 is the most prolific turbine ever built, and most commonly found on small single engined helicopters, so most aviators using this kind of engine are obviously happy with the reliability or else there wouldn't be so many flying! Suggestions that use as a helicopter engine means they cannot be used on fixed wing aeroplanes says more about the lack of understanding of turbine engines on the part of the opinion holder than it does on any real science.
Redesigning Nomads to use the RR250 B17F version makes more sense than you think, because it will be a relatively simple change where the costs can be more easily amortised, and the performance requirement is well within the design capability of the newer engine. By comparison, changing to the PT6 would require tens of millions of dollars worth of redesign and no-one these days has that kind of money in the Nomad end of the market.
People need to get consistent with their arguments. Investors only invest if they have a fair chance of getting their money back. At the beginning of the Nomad programme, Australia's usual bunch of naysayers were already trying to kill the aircraft development for some other "nationally important" reasons, and that's why the investment wasn't there up front, and we are left with a design compromise. Other than the fact that this is always the case in aviation, or any other manufacture for that matter, the poorly supported local aircraft industry is following the investment capital overseas. Whining about it now won't help, and PT6 protagonists can bleat all they like about their beloved engine, but maybe they just need to get out a bit more?