It took the work of more than 250 employees to bring Pratt & Whitney's newest engine family to life. The PT6-E Series engine, unveiled Monday at the NBAA Business Aviation Convention and Exhibition in Las Vegas, introduces features never before seen in general aviation.
The PT6-E takes innovation to a new level. It is the first turboprop engine to offer a dual-channel integrated electronic propeller and engine control system. Mario Guerra, program manager for the engine program, was proud to see the technology come to life.
“This is arguably the most complex Electronic Engine Control system we've ever done," Guerra said. “We did everything we said we wanted to do. We didn't compromise on our vision."
That complexity translates to simplicity for pilots and operators, the engineer explained.
“The first thing a pilot will notice is the ease of operation," Guerra said. “The system automates many of the steps the pilot had to do in the past, and lets the pilot focus on flying."
Read on to learn more about the latest addition to the world's No. 1 general aviation engine family.
Where it all started
Mario Guerra: The idea for the PT6-E series, putting a FADEC, or Full Authority Digital Engine Control, on a PT6, initially started in 1998. A first business case emerged in 2008, but it wasn't until 2012 that the project finally gained speed. The first engine to test was in 2014, first flight in 2017, and the engine and aircraft were certified this year. Over 250 employees worked on the program, including our team in Lethbridge, where it will be built. Hundreds more technical experts from our partners and suppliers worked on the project.
A propeller control system is very complex, with many design and operating parameters. In 2013, we brought together 18 of our best engineers, Woodward, our partner on the program who designs and manufactures the fuel control unit, electronic engine control and propeller control unit, as well as propeller manufacturer and program partner Hartzell. That was a breakthrough workshop. The ideas and requirements we discussed gave rise to the design of the engine and system we have today.
Advanced technology for flying and operations
Mario Guerra: We have FADECs on many other engines, like the PW300 and PW800 engine families, but what makes the PT6-E different is the addition of the propeller control system. This is arguably the most complex Electronic Engine Control system we've ever done, and a first of its kind in the general aviation market.
The first thing a pilot will notice is the ease of operation. We automated the steps that a pilot needs to start and manage the engine and propeller. Next, they'll notice the performance. We designed a new compressor turbine and optimized turbine cooling to deliver 5% more thermodynamic power and 10% more mechanical power. That's a big selling feature for our operators who are looking for performance.
When it comes to the service experience, the engine was based on the PT6A-67P which has 300-hour line maintenance intervals and a 3,500-hour time between overhaul. We were able to extend those intervals to 600 hours and 5,000 hours, respectively, because of the improved engine durability and extensive testing on existing components such as fuel nozzles. The control system ensures that the engine always operates at peak efficiency, for less engine wear and tear. The engine flight data downloads on landing, and allows the operator to know when and if a hot section inspection is required. That same data goes to our predictive analytics team and engineers, who use it to provide personalized customer service to maximize flying time.
Simply performing
Mario Guerra: It's a challenge to deliver a program of this size without making some trade-offs along the way. But I'm proud that we did everything we said we wanted to do. We didn't compromise on our vision. We succeeded in making the system as simple as possible, without adding redundant components that would add weight or make it harder to operate and maintain.
You can see the simplicity when you look at the engine. It's so clean – it's naked! There are fewer components, and that means higher reliability and less maintenance – we were able to eliminate 40% of line maintenance tasks. Without a lot of externals, it's an easy removal. In terms of operation, the system automates many of the steps the pilot had to do in the past, and lets the pilot focus on flying.
'A good day to fly'
Mario Guerra: There is nothing harder than certifying an engine. By Dec. 20, 2017, I had been in Switzerland for three weeks for the first flight with the engine, after thousands of hours of system, component and engine ground tests. PT6 engines aren't tested on our Boeing flying test beds. The first flight test was done on the single engine Pilatus PC-12 turboprop plane. It's at these moments when you realize that we truly do hold people's lives in our hands.
The test pilot was an ex-military pilot, risk averse by nature and by training. He had concerns, and we needed to work through those before he would perform the test flight. For more than four hours I explained every aspect of the system, engine design and decision we made in detail. When I finally told him, “If I could, I'd come with you," the pilot paused and said, “Well, that changes everything." Looking from the sky to his co-pilot and engineer, he said “it's a good day to fly. Let's go."
The emotions of that first flight were indescribable, a mixture of intense pressure, pure adrenaline and absolute elation.