There are operational differences as well.
1. A prop strike in a PT6 is less involved than in a TPE331 for instance, as it's not connected to everything else as it is in the Garrett.
2. On the other hand, the TPE331 is certified to run on pretty much anything you'll feed it, including the occasional Avgas, Diesel, Mogas run as the turbine stage is less delicate. Not something you can do with a PT6. More bush, if you wish.
3. Garrets are slightly more efficient (burn less fuel) and they have higher TBO's (5400hrs on most of them).
4. On the other hand, the Garretts need a lot more electric power to get started as they have to spin the prop before they light up. This is also why they're susceptible to hot starts if the battery is weak, as it won't push enough cold air through the core.
Last edited by AdamFrisch; 18th Nov 2012 at 23:00.