Crew Fatigue???
The flight was the sixth of the day for the crew, who had been on duty nearly 15 hours that day, within FAA-approved limits, investigators said.
Would you be happy to be operated on by a surgeon who had been on duty for 15 hours? No? But you are happy to be flown by a crew on an old turbo prop that have!
Another case of a HGV driver has a more restrictive duty day than an airplane pilot! Makes sense don't it?