PT6A-67D Power settings ??????
When I used to fly them (Ds only), the operator had done flight tests to see if there was any better cost benefits to be found.
What they found for an average temperature of ISA + 20 For the D was, any sector over 40min, we went to F230 or above and used a cruise regime that was found to be just below High Speed Cruise as follows:
Prop setting remained 1550 rpm
Torque - F250 - 2100ftlbs - FF 640 pph - TAS 260
F240 - 2200ftlbs - FF 680 pph - TAS 264
F230 - 2300ftlbs - FF 720 pph - TAS 268
These settings gave a SAR that was better than Intermediate Cruise figures but gave us better sector times.
It was also 200ftlbs below High Speed Cruise and gave us the option of if the anti ice was needed, we could push the levers back to the 2100 - 2300 setting, the fuel flow then was the same and we only lost a couple of kts TAS - the penalty was increased temperatures, but still well below max.
Any altitude below F230, we went to Intermediate Cruise, and at F180 and below we set a max FF of 800 pph and matched torques to limiting side, otherwise she was too thirsty (all prop settings stayed at 1550 for ease of operation, but a bit more noisy than 1400).
The D hates anything below F230, and she was made to get up there quickly and stay as long as possible.
Hope this helps.
TWB