There are not many common problems with the PT6. The early models had problems with low TBOs and HSI intervals. But as the engine has eveloved over the years the Modern Machines are much better. Having TBOS of around 3500 Normally with exensions upto 5000 hrs for FAR 135 and 121 ops ( Charter and RPT), THE ENGINE HAS A GREAT RECORD! But dont belive its bullet proof cause it aint. I have around 2000 hrs on PT6 powered Aircraft without a problem,( except a machine I wa sscheduled to fly had a compressor failure on the ground after start ). Another mate of mine had one go in the Air, but hed had 3000 hrs on PT6s at that time. Both these failures were incidentally on PT6-20 Engines which have had problems in the past with low TBOS and single stage nozzles which give high Start temps. The later versions and had dual stage nozzles which gave a staggered start temp much better.
See you tommorow
Regards
Sheep
P.S. Your home work tonight. Go and get that POH and read about the PT6. Define for me the BETA Range and Reverse range of your props in degress and the specified limits on N1 for these operations and temp limits too?