The PT6A is the undisputed leader in turboprop applications.

The PT6A-135A is the result of four decades of improvement. The power section can produce up to 944 ESHP, so it does not work very hard to produce 750 SHP. That translates to lower maintenance costs and better fuel efficiency. Flat-rated to 550 SHP in this application, the Silverhawk 135 engine has generous ITT and N1 margins.

The earlier PT6A-20 and -21 engines were sometimes at their temperature limits on the ground, and were always working hard. That shows up in overhaul costs and cycle limits.

The performance benefit of the 135A engine is apparent as you climb to higher altitudes, and it continues to produce rated power.

The following chart is for a specific airplane on a given day, but it clearly shows the difference between 40-year-old engine technology and the Silverhawk 135 upgrade.

Max Cruise Comparison