Basler Turbo -67
Well after a long time of lurking time to dip a toe into the water of posting so to speak, Rory, reference the thought of turbo propping a DC3 try googling the Basler Turbo-67 they already did it ! and funnily enough yup you guessed it PT6's!
Did see the program hard to miss it really after the blanket saturation of the adverts on Quest for it, but great TV all the same, OK some of the maintenance and practices made me wince a bit but hey they are doing the job and still flying so they cant be doing it too badly now can they!
I can only think really that the main reasoning behind still operating that vintage of aircraft is as mentioned in other posts cost of spares and aircraft inherent robustness, being involved in the maintenance world of some elderly aircraft myself although not of that vintage i have to say, very often they can keep on going and remain economically viable to a small niche operator like Buffalo long after conventional wisdom would say otherwise, after all if you are getting a lot of your spares from breakers or your own older parted out aircraft they will usually be cheaper than in service types of today, so looking forward to seeing the next episodes.