Model PT6A-21

Power 550 SHP

Diameter 19 ''

Length 62 ''

RPM 2200

The PT6A engine family remains the world’s most popular engine in its class and is one of P&WC's greatest success stories. Experience gained from the PT6A has helped spawn many of the engine families that have made P&WC a world leader in the gas turbine engine market.

Dependability and versatility have been the hallmarks of the PT6A and continue to be the foundation of the many new PT6A models incorporating the very latest advanced technologies. New aerodynamic and material technologies have enabled the PT6 engine to gain more power without significantly increasing in size. Other innovations have reduced emissions, increased maintenance intervals and further enhanced ease of operation with the introduction of digital electronic control to small gas turbine engines.

Ranging in power from 500 shp to over 2,000 shp, PT6A engines are available in more than 65 models, offering unsurpassed flexibility and capability for a variety of applications. The numbers speak for themselves: members of the family currently power aircraft in service with more than 6,500 operators in more than 170 countries. More than 36,000 PT6A engines have been produced since the family entered service in the 1960s, accumulating 300 million flying hours. PT6A engines have demonstrated their versatility in powering aircraft applications spanning the airlines, general aviation, business, agricultural and utility markets.

Operators of PT6A engines are supported by P&WC’s industry-leading global customer support. This includes over 30 P&WC-owned and designated service facilities around the world, more than 100 field support representatives on all major continents, a 24/7 Customer First Centre for rapid expert support, the most advanced diagnostic capabilities for this market and the largest pool of P&WC rental and exchange engines in the industry.

The PT6A engine family continues to advance, incorporating the latest technologies in the drive to exceed our customers’ expectations in performance, reliability, durability, fuel consumption and environmental friendliness. More than 65 PT6A models have been produced, ranging in shaft horsepower power from 500 shp to 2,000 shp. New aerodynamic and material technologies have enabled the PT6 engine to gain more power without significantly increasing in size. Other innovations have reduced emissions, increased maintenance intervals and further enhanced ease of operation with the introduction of digital electronic control to small gas turbine engines.

The novel PT6A configuration has proven a key attribute to its success: its rearward, reverse flow inlet and forward facing turbine section providing fast maintenance turn-around through on-wing hot section refurbishment in most aircraft installations. The PT6A is a two-shaft engine with a multi-stage compressor driven by a single-stage compressor turbine and an independent shaft coupling the power turbine to the propeller through an epicyclic concentric reduction gearbox.

The PT6A family of engines embodies three series of models with increasing power levels, referred to as PT6A ‘Small’, ‘Medium’ and ‘Large.’ The increased power levels are achieved through the increase of compressor air flow and increased number of power turbine stages. Most recent models enjoy the advantage of additional advanced technologies in materials, turbine cooling and aerodynamic design.

Multi- stage axial and single-stage centrifugal compressor

• Reverse flow, radial inlet with screen for FOD (Foreign Object Damage) protection
• Large PT6A models incorporate 4-stage axial and 1-stage centrifugal
• Small and Medium PT6A models incorporate 3-stage axial and 1-stage centrifugal

Reverse flow combustor

• Low emissions, high stability, easy starting, durable

Single-stage compressor turbine

• Cooled vanes in some models to maintain high durability

Independent ‘free’ power turbine with shrouded blades

• Large PT6A models incorporate 2-stage axial turbine
• Small and Medium PT6A models incorporate 1-stage axial turbine
• Forward facing output for fast hot section refurbishment

Epicyclic speed reduction gearbox

• Enables compact installation
• Output speed optimized for highest power and low propeller noise
• 1,700 to 2,200 rpm output speed

Electronic engine controls on many PT6A models

• Other models incorporate various control modules and over-ride features to promote ease of operation and safety of flight.

	Thermodynamic Power Class* (ESHP***)	Mechanical Power Class* (SHP)	Propeller Speed (Max. RPM)	Height** (Inches)	Width** (Inches)	Length** (Inches)
PT6A ‘Small’ (A-11 to A-36)	670 to 950	500 to 750	1,900 to 2,200	21 to 25	21.5	62
PT6A ‘Medium’ (A-38 to A-45R)	1,090 to 1,318	700 to 1,200	1,700 to 2,000	22	19.5	67 to 72
PT6A ‘Large’ (A-52 to A-68)	1,218 to 1,845	1,050 to 1,700	1,700 to 2,000	22	19.5	67 to 76

* Powers are approximate values at take-off. Available at sea level, standard day, static conditions, uninstalled.

** Dimensions are approximate values.

*** Equivalent Shaft Horsepower: includes estimated equivalent contribution of exhaust thrust.

• Beechcraft King Air C90A/B/SE
• Turbine Air Bonanza