Turbine TBO is based on hours...at least in the engines I'm familiar with.

Yeah everything I've seen says turbines are overhauled by the hours flown. So I don't see how short trips would be killer on them compared to a piston. So I guess that's why I was confused with those who said turbines would be beat up more on short hops when Caravans do this stuff every day all around the world.

Low altitude flights, ie short trips, are hugely inefficient because turbines efficiency is at the mid to upper 20's in turboprops. The overhauls aren't as much on cycles as they are hours, but cycles are harder on the engines because typically some of the hottest temps on an engine are during start. It's more of an issue in the resale market. Cycles also mean more landings on an airframe, some aircraft are sensitive in this realm, but once again, not a standard issue on turboprops.

Example: TBM850 at 3000ft is burning 75gph, maybe 240ktas, at 27000, 57gph @ 310ktas.

Yeah it makes sense, I just assumed that a lot of those issues would be similar in pistons in terms of wear and tear. And I wouldn't think that 9K would be too concerned about resale value since they seem to like taking planes to their max life limit or longer

Huh... One of the guys at the company told me about the "cycle" deal. Oh well, guess he was mistaken. I didn't know one way or the other.

I believe it is time or cycles which ever comes first. I think Cape Air would cycle out before they timed out on an overhaul. It has to do with the higher temperature every time you start. At least on PT6's. I am not sure on Garretts.

As far as turbine effeciency, I fly on a Caravan alot and on the longer legs of about 2 hrs we go up to 15K, above that the engine power drops off. For the shorter legs of less then an hour usually 6-7K. The Van would work well with this lower altitude effeciency, plus its the Van, the Van is awesome!!!

Just talked with our Service manager to confirm the Engine overhaul on the PT6. There are a few components that are limited to cycles, but we as a Mx facility do not mess with those. There are the 1800hr hot section, and 3600hr Overhaul intervals, but that's really it. As long as an operator keeps track of the cycle logs, it would be beneficiary towards the long-term Mx of those engines.

There are MX programs available for the PT-6 to extend TBO to 8,000 hours.

The van also has a landing gear TBO and I think it is every certain number of cycles, I really can't remember.