The PT6A-20 engine has stood the test of time. Frankie Williams Owns and Operates Souther Field Aviation in Americus, GA. He maintains 35 agricultural plances for othe operators and does between 85.000 to 100,000 sprays a year. Frankie brought his first -20 about 16 years ago and still flies it today in his Turbine Brave airplane. "It is pretty much a maintenance free engine. If you do the scheduled maintenance you don't have to do anything else," Williams said.
Is the PT6A-20, an engine from the past, thriving, or on life support? Pratt and Whitney’s interest in supporting the -20 has waned over the years. Manuals and parts are no longer being supported. This presents a nightmare when it comes to keeping your engine running. Overhaul facilities like Turbines Inc. has been overhauling and repairing -20’s for more than 30 years. “We have the experienced staff who have been working on these engines and know them inside out,” Turbines Inc. General Manager Jim Peleck said. In addition, Turbines Inc. introduced the PT6A-20 to the Agricultural market with the first ever conversion of a round piston engine to a turbine powered spray plane, and still holds the STC for that conversion on an Ag Cat.
When your hot section is due for inspection and you start to preplan your material needs, the problem will become obvious. There are no parts available. Pratt will still sell you the CT blades, 3023401, which are listed in the 2016 pricing guide at $717.00 a blade. Yes, almost $42,000 for a set of blades, which is equal to almost 25% of the value of your engine. The rest of the hot section parts become a logistical nightmare of cobbling together surplus material from multiple vendors. The individual vanes in the 20 are the 3019551 CL and they are not supported by Pratt and since they are a classed item finding one is hard enough, finding the correct class to produce your 12.0 average is monumental. “We still hold -20 parts in stock and continue performing hot section repairs as well as full overhauls on them. The PT6A-20 is alive at Turbines Inc. but we know the clock is ticking,” 35-year A&P Mechanic veteran Don Nichols said.
So is there light at the end of the tunnel? There just may be, in the form of PMA parts. The alternative parts market just may be the answer to the continuation of the -20 engine. Shroud segments are available in the PMA market from a couple of vendors and if the list of available PMA parts continues to grow, it just may breathe life into this workhorse of an engine. If just a few parts are able to reach the market then the life of the PT6A-20 could be extended and provide alternatives to upgrading your power plants or in the worst case removing more functioning aircraft from the industry. “For the money I have invested in a -20, I have definitely gotten a return on it. The fuel consumption is 32 gallons an hour. It is a lot more economical to operate. I couldn’t be happier with the engine,” Williams said.
Frankie Williams’ Turbine Brave airplane
Don Nichols working on PT6A-20 engine at Turbines Inc.