Honeywell TPE331 vs. PT6A-52

Cessna Citation inspection

For smaller turboprop aircraft, there has traditionally been two, primary engine choices: the Pratt & Whitney PT6 and the Honeywell TPE331. The PT6 is often found in Cessna Caravans and Beechcraft King Airs, while the TPE331 is found in Twin Commanders, Cessna Conquests, and MU-2’s.

Both are powerful engines that help with faster ascent and quicker take-off. But which is better? Today we’re looking at the Honeywell TPE331-10 vs. the PT6A-52 to see which engine may be the best fit for your aircraft and need.

Honeywell TPE331-10

The Honeywell TPE331 engine is a turboprop engine that was originally built in 1959 for the United States military. It was designed to power military aircraft and helicopters and rival the scaled-down version of larger engines that other competitors were introducing to the market at the time. 

The Honeywell TPE331 is a single-shaft, direct drive turboprop with an integral gearbox. Its compact style lends itself to a variety of airframe installations. The direct drive feature is unique and allows for faster engine response time and a considerable increase in fuel efficiency. The operating altitude is 35,000 feet.

The Honeywell TPE331-10 is available as an upgrade for the older version -5 or -6 engines. The -10 conversion offers exceptional performance with a higher thermodynamic rating than other models. The -10 engine can maintain its maximum flat rate power until 16,000 feet compared to about 6,000 feet on earlier versions.

The basic Honeywell TPE331-10 engine includes:

  • Hydro-mechanical Fuel Control system
  • Propeller governor
  • Fuel pump
  • Fuel shutoff valve
  • Fuel anti-ice heating system
  • Dual ignition system
  • Lubrication system
  • Propeller-pitch control
  • Oil temperature-sensing bulb
  • Negative-torque-sensing (NTS) system
  • Beta-pressure sensing switch
  • Torque and temperature limiting (depending on airframe installation)
  • Fuel purge system
  • Air speed and ambient pressure ratio transducer (depending on airframe installation)

Optional features to the basic engine can include a Single Red Line Computer and water methanol augmentation


Diameter: 22 inches (530mm)
Dry weight: 375 lbs. (approx.)
Compressor: Two-stage centrifugal
Combustion Chamber: Singular annular, Reverse Flow
Turbine: Three-stage axial
Maximum power output: 840 to 1000 SHP depending on model.
Overall pressure ratio: 10.55:1

Pratt & Whitney PT6A-52

The Pratt & Whitney Canada PT6 is a turboprop engine that was designed in 1958 and entered service in 1964. The PT6 consists of two sections: a gas generator with accessory gearbox and a free power turbine with reduction gearbox. The PT6 is unique in that the engine is seemingly mounted backwards with the intake at the rear and the exhaust in the front. The operating altitude is 41,000 feet.

The PT6A-52 engine is an upgrade to the PT6 and integrates unprecedented performance in the turboprop market. The upgrade exchanges the existing PT6-41 or PT6-42 engines with a more efficient engine design that extends operating temperatures. The PT6-52 boasts thermodynamic horsepower that optimizes climb and cruise performance.

The PT6A-52 includes:

  • Multi-stage axial and single stage centrifugal compressor
  • Reverse flow combustor
  • Single stage compressor turbine
  • Independent free power turbine with shrouded blades
  • Epicyclic speed reduction gearbox
  • Electronic engine control (EEC)


Diameter: 22 inches
Dry weight: 450 lbs. (approx.)
Compressor: Two-stage centrifugal
Combustion Chamber: Singular annular, Reverse Flow
Turbine: Three-stage axial
Maximum power output: 850 shp
Overall pressure ratio: 10.0:1

Find The Right MRO For Your Honeywell or P&W Engine

Finding the right MRO for your Honeywell or P&W starts with determining who you can trust. At Winner Aviation, we are a Honeywell authorized service center and also have extensive experience working with Pratt & Whitney engines.

If you need an engine upgrade, scheduled inspection, or simply need help troubleshooting an issue, we’re here to help. Contact our maintenance team today.

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