THE PT6 ENGINE MILESTONES

It’s the remarkable story of a remarkable engine. With more than 51,000 engines delivered to power some 130 different applications, the PT6 engine can tell quite a story of creativity and transformation. While we had a lot to choose from, we’ve put together a list of milestones for the engine as we mark its golden anniversary.

1957 – P&WC assembled a team of 12 talented young engineers after studies showed a market opportunity for 500 shp (shaft horsepower) class turboprop engines in the aircraft market then powered by piston engines. P&WC saw an opportunity to channel some of the profits from its piston engine spare parts business towards the development of gas turbine engines smaller than those made by its U.S. parent.

Twelve key men on the PT6  engine design team: Gordon Hardy, Jim Rankin, Fernand Desrochers, Fred Glasspoole, Ken Elsworth, Allan Newland, Pete Peterson, Hugh Langshur, Jean-Pierre Beauregard, Elvie Smith, Dick Guthrie and Thor Stephenson.

Twelve key men on the PT6 engine design team: Gordon Hardy, Jim Rankin, Fernand Desrochers, Fred Glasspoole, Ken Elsworth, Allan Newland, Pete Peterson, Hugh Langshur, Jean-Pierre Beauregard, Elvie Smith, Dick Guthrie and Thor Stephenson. © Library and Archives Canada. Reproduced with the permission of Library and Archives Canada. Source: Library and Archives Canada/Credit: Bruce Moss/Weekend Magazine collection/PA-167966.

1963 – It’s what our celebration is all about. In December 1963, P&WC shipped the first PT6 production engine, the PT6A-6, to Beech Aircraft Company for its Beech 87, which later became the King Air. The PT6A-6 was a highly innovative gas turbine that represented a significant advance in technology from the traditional piston-driven engines used to power small aircraft.  Gas turbines have a higher power to weight ratio than piston engines.

The first PT6 production engine.

The first PT6 production engine. P&WC Archives (Records and Information Management).

1967 – Piper’s PA-31 Navajo took its first flight powered by PT6A-20s. Piper had enjoyed enormous success building light aircraft since the 1930s, but it took P&WC years of effort to get Piper to adopt turbine engines and move away from their traditional reliance on piston-driven engines.

1968 – P&WC’s ST6L73 engine (a derivative of the PT6A without the gearbox second stage) entered into service as an auxiliary power unit (APU) for the Lockheed L1011 airliner.

1968 – Bell Helicopter placed its initial order for P&WC’s first turboshaft, the PT6T Twin-Pac® engine

1970 – P&WC’s PT6T Twin Pac® entered into service. It is two engines coupled in a single package to power medium-sized, twin-engine helicopters.

1970 – The United States Military ordered 294 Bell 212s under the designation UH-1N equipped with PT6T Twin-Pac® turboshaft engines. Delivery also began in 1970.

1973 – The second-stage power turbine was introduced on the PT6A-41. This was a step change in engine power and efficiency.

1979 – An Air Tractor agricultural aircraft is powered by a PT6A engine and flies to the National Agricultural Aviation Association convention in Las Vegas – the first time such a combination was displayed in public.

AT-400, Serial No. 400-0244, the first Air Tractor aircraft powered by the Pratt & Whitney Canada PT6 engine.  The AT-400 was originally certified with the PT6A-15AG engine.

AT-400, Serial No. 400-0244, the first Air Tractor aircraft powered by the Pratt & Whitney Canada PT6 engine. The AT-400 was originally certified with the PT6A-15AG engine. © Air Tractor Inc.

1981 – By this year, PT6T engines powered 1,000 helicopters, mainly those manufactured by Bell Helicopter.

1982 – Cessna Aircraft Company, world renowned for its business jets, selected the PT6A-114A engine for its all-new multi-mission Cessna 208 Caravan aircraft. The aircraft would go on to become a highly popular and tireless workhorse in applications around the world. One of the Caravan’s largest customers today is express carrier FedEx, which currently has a fleet of approximately 350 Caravans.

1984 – The Piaggio Avanti became one of the first aircraft to be powered by the PT6A-67 engine (later powered by the PT6A-66). To date, it is the fastest certified twin turboprop and is known today as “the Ferrari of the Skies.”

1984 – First-stage Integral Bladed Rotor (IBR) technology was introduced on the PT6A-65 model resulting in fewer parts in the engine and better efficiency.

1985 – The PT6B family of turboshaft engines made its debut with the PT6B-36, which would power the twin-engine Sikorsky S-76B. The new engine upped the power of the S-76 by 46 percent compared to previous models of the aircraft.

1987 – Socata officially launched its TBM 700 aircraft at Le Bourget air show, and in 1989 the company ordered 50 PT6A-64 engines from P&WC. Delivery of the first TBM 700, powered by the PT6A-64, took place in 1990. With seating for up to seven people, the TBM 700 is a passenger aircraft used in a variety of applications.

1990 – The last Embraer Bandeirante commuter aircraft was delivered. Since Brazil’s Embraer SA installed the PT6A-27 (and, later, the PT6A-34) in the 19-seater EMB110 Bandeirante in the late 1960s, nearly 500 of the aircraft had been made. Since then, over the course of 45 years, Embraer has selected more than half a dozen different PT6A series models, in addition to models from the PW100, PW600 and PW500 families, to power its turboprop aircraft.

1991 – In May, the Pilatus PC-12 flew for the first time powered by the PT6A-67B engine. It quickly became popular for missions ranging from airline and air-ambulance service to cargo transport.

PC-12 first flight.

PC-12 first flight. © Pilatus Aircraft Ltd

1991 – The PT6A-68/1 turboprop is selected for the Embraer EMB-312H Super Tucano trainer, which is designed to operate in high temperature and humidity conditions in extremely rugged terrain.

1993 – Single-crystal blade technology was first introduced on the PT6A-67A which resulted in increased temperature capability for the engine allowing it to operate at higher gas path temperatures and providing more power for the same size engine.

1996 – The U.S. Navy and U.S. Air Force teamed up to find a replacement for their Cessna T-37 and Beechcraft T-34C aircraft used to train entry-level pilots. In this year, the Joint Primary Aircraft Training System (JPATS) contract, valued at as much as US$ 9 billion including support contracts, was awarded to Raytheon Aircraft (as Beech was then known), which proposed a modified Beech/Pilatus PC-9 Mk II aircraft powered by a single PT6A-68 engine. The awarding of the contract to the aircraft, later designated the T-6A Texan II, was a surprise because conventional wisdom at the time suggested that it would be awarded to a jet. The first T-6A Texan II flew in 1996, and by 2012 more than 600 engines had been delivered.

1998 – Continuing with the trend, P&WC and Pilatus executives met in Nuuk, Greenland, to sign a contract after Pilatus selected the PT6A-68B for its new PC21 pilot trainer. As a demonstration of the confidence that P&WC and Pilatus have in their combined products, P&WC executives made an 11½-hour round trip aboard a Pilatus PC-12 powered by a 1,200-shp PT6A-67B while Pilatus executives in Switzerland travelled to Nuuk in a single-engine aircraft; a round trip of 4,650 nautical miles.

Contract signature (PC-21 / PT6A-68B) at Nuuk (Greenland).

Contract signature (PC-21 / PT6A-68B) at Nuuk (Greenland). © Pilatus Aircraft Ltd

2000 – The Piper Malibu Meridien, powered by the PT6A-42A, was certified. The aircraft is known for its ability to climb to altitude quickly and efficiently regardless of most weather and turbulence.

2001 – The PT6C, the third turboshaft family based on the PT6A engine, debuted in this year with the PT6C-67C to power the twin-engine 15-seat AgustaWestland A139.

2003 – Aviation history was made this year when the innovative Bell/Agusta AB609 tilt rotor flew for the first time powered by two PT6C-67s. Later renamed the AgustaWestland AW609, the tilt rotor lands and takes off vertically like a helicopter but cruises like a turboprop.

2003 – In September of this year, Ken Borek Air conducted a daring rescue flight from its base in Calgary, Alberta to the Amundsen-Scott American research station in the Antarctica aboard a Twin Otter turboprop powered by PT6A-34 engines. It then brought an ailing research worker to Punta Arenas, Chile, for medical assistance. The flight braved extreme cold and darkness at a time when aircraft rarely venture to the region.

2003 – The Epic LT aircraft was announced at the annual fly-in EAA AirVenture Convention in Oshkosh, WI.  The Epic LT is a six-seat business turboprop in the experimental, kit-built category powered by the PT6A-67A engine. 

Epic LT powered by the PT6A-67A engine.

Epic LT powered by the PT6A-67A engine. ©Jessica Ambats. Reproduced with the permission of Epic Aircraft.

2006 – P&WC signed a five-year agreement with Blackhawk Modifications for 550 new PT6A series engines under P&WC’s Converter Enhancement Program (CEP). Under the agreement, Blackhawk Modifications would use the P&WC engines for its various engine-upgrade programs on Raytheon King Air series, Cessna Conquest 1 and Piper Cheyenne turboprop aircraft under Supplemental Type Certificates (STCs).

First King Air Upgrade.

First King Air Upgrade. © Blackhawk Modifications, Inc.

2007 – Air Tractor’s largest aircraft, the AT-802 powered by the PT6A-67F, was certified. Air Tractor was founded by Leland Snow in 1972 and its aircraft can now be found on hundreds of farms in the United States and around the world. It has an extensive line of aircraft, powered by the PT6A, that feature 400- to 1,000-gallon capacity and the ability to spray both liquid and dry products.

2007: Air Tractor’s largest aircraft, the AT-802 was certified with the highest power PT6A engine, the PT6A-67F.

2007: Air Tractor’s largest aircraft, the AT-802 was certified with the highest power PT6A engine, the PT6A-67F. © Air Tractor Inc.

2007 – The PT6C-67E was selected to power the Eurocopter EC175, with entry into service expected in 2013. The EC175 is billed by Eurocopter as the roomiest, safest, most comfortable, easiest to fly, cheapest to maintain, most cost-effective seven-tonne robust workhorse in the world.

2007 – Viking Air revived de Havilland Canada’s Twin Otter aircraft, which had been manufactured between 1965 and 1988 in Toronto. Viking purchased Type Certificates from Bombardier Aerospace for all out-of-production de Havilland aircraft and restarted production of the new Series 400 Twin Otter with powerful PT6A-34/-35 engines.

Viking President & CEO, David Curtis, gives two thumbs up after completion of the initial flight of the very first Twin Otter Series 400, MSN 845, Calgary, AB, February 2010.

Viking President & CEO, David Curtis, gives two thumbs up after completion of the initial flight of the very first Twin Otter Series 400, MSN 845, Calgary, AB, February 2010. © Viking Air Limited

2007 – P&WC signed a five-year agreement with Standard Aero for 531 new PT6A series engines under its Converter Enhancement Program (CEP). Under the program, Standard Aero would use the PT6A engines for various turboprop aircraft-upgrade programs.

2008 – Quest Aircraft Company delivered its first KODIAK turboprop powered by a PT6A-34 engine. Quest was created in 2001 with the purpose of designing and manufacturing a backcountry utility aircraft suited to the demanding needs of mission and humanitarian organizations. The KODIAK’s commercial success subsidizes roughly every 10th airplane produced, which is then delivered to a participating not-for-profit organization.

First flight of s/n 001 in early 2007.

First flight of s/n 001 in early 2007. © Quest Aircraft Company, LLC

© Quest Aircraft Company, LLC

2010 – The Computerized Visual Inspection System (CVIS) was introduced to the manufacturing process for PT6 engines. It is an automated inspection tool that verifies the integrity of the external assembly of new engines. CVIS includes a robot and a camera that moves over the exterior of an engine and takes up to 300 pictures. The robot then compares the pictures with “master” photos that show how the external assembly is meant to look. Any variance is identified by the robot. Almost all new P&WC engines are now analyzed by CVIS.

2011 – P&WC and Thrush Aircraft announced a 10-year General Terms Agreement, which covered a broad suite of commercial arrangements. The agreement extended the partnership between P&WC and Thrush Aircraft, one of the leading agricultural manufacturers in the world.

© Thrush Aircraft, Inc.

2011 – The TBM 700, powered by the PT6A-64 engine, became the first single-engine aircraft ever authorized to fly from Hong Kong to Beijing; this voyage was part of a 10-week trip around the world.

2012 – Pacific Aerospace delivered two skydiving-configured P-750 XSTOL aircraft to operators in Europe. Powered by PT6A-34 engines, the aircraft is popular with skydive operators because it can climb to 12,000 feet, unload up to 17 parachutists and then return to base in 10 minutes.

2012 – P&WC and Viking Air announced they have entered into a 10-year General Terms Agreement to supply PT6 engines, including the PT6A-34 for the Twin Otter aircraft.

Viking’s first Twin Otter Series 400, MSN 845, owned by Zimex Aviation of Switzerland gets ready for take-off while on duty in Uganda, June 2011.

Viking’s first Twin Otter Series 400, MSN 845, owned by Zimex Aviation of Switzerland gets ready for take-off while on duty in Uganda, June 2011. © Viking Air Limited

2012 – In July, Cessna announced that it had chosen the newly certified PT6A-140 engine to power the latest innovation in the Cessna line: the Cessna Grand Caravan EX. The PT6A-140 is built at P&WC’s facility in Lethbridge, Alberta, which was designated as the company’s Centre of Excellence for the PT6 engine in 2007. The engine, which incorporates highly advanced technologies, is the most powerful PT6 engine in its class and provides the best power-to-weight ratio.

2012 – At the October convention of the National Business Aviation Association (NBAA) in Orlando, Florida, Hawker Beechcraft ceremoniously delivered a PT6A-powered King Air business turboprop, its 7,000th, to Herman and Kittle Properties of Indianapolis. The aircraft has been in continuous production since 1964, and by 2012 it had accumulated an astounding 45 million hours of flight.

2013 – The PT6 engine fleet has exceeded 380 million hours of flight; that’s 10 times more hours of flight than its closest competitors.

It has been 50 years of impressive milestones in just about every major airframe OEM in the industry. The engine’s untouchable record for hours of flight means that it has been certified for single-engine Instrument Flight Rules (IFR) for commercial flights. This has allowed the PT6 engine to power an entire new industry virtually on its own.

That’s just one more milestone in the making of a legend.

COVER PHOTO: The P&WC Beech 18 test bed on a proving flight from Downsview in 1961. HB109 (later CF-ZWY-X) made 719 flights and logged 1,068 hours testing many PT6 models and propellers. It was retired to l'École aéronautique in St. Hubert after its last flight on June 3, 1980. P&WC Archives (Records and Information Management)


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