Clunck:
I was really talking about 60 to 70 year old round engines and the airframes in which they're still operating.
Surely it must be about calling time on the remnants of WWII era aircraft still operating in revenue passenger transport roles today?
Your point about the disappearing availability of skilled technicians and the lack of incentives for young people to enter the trades today is a very real concern for the aircraft and engine maintenance business, perhaps more significant than the age of the hardware itself.
Age of the design, as such, is not the problem (witness the roll-out yesterday of the latest model 737 Max 8, 49 years after the 737-100 rolled out of Renton) - a testament to continuously updating the technology as it evolved.
But DC-3's and C-46's in 2015??