The Science of Evolution

Introduced in 1965, the 575 shp 331 engine evolved into the -1 Century series engines rated at 715 shp. Still occupying the same frame size, the compressor was uprated in 1969 to create the first member of the 840 SHP family, the TPE 331-3.

The TPE 331’s evolution continued a year later with the introduction of the flat-rated versions of the -3, the -5 the -6. The TPE 331-5 was the engine placed on the turbine Aero Commander. In the mid -70s, the -8 engine appeared. While the takeoff thermodynamic rating only increased modestly over the 840 SHP series, the altitude performance was greatly enhanced. The increased demand for altitude performance fostered the development of the 1,000 shp -10 engine, certified in 1978.

A product of evolution, the TPE 331-10T engine has earned a reputation of significant performance and reliability. The engine has been installed on a variety of executive, regional, utility, agricultural and military aircraft throughout the world.

The most popular and highest performing conversion using -10T power has been the Twin Commander 690A, B, C, & D models.

High Performance Machine

The -10T Twin Commander Hallmark

Prototyped in 1993, and debuting during the 1993 NBAA show, the -10T Twin Commander matches any aircraft legendary for its performance to an even higher performing engine. The result is a performance conversion so popular, over 170 -10T Twin Commander aircraft are flying.

  • 300+ KTAS
  • Full power to 16,000 feet
  • 3,500 fpm initial rate of climb/Greater than 2000 fpm to FL200
  • 12 minutes to FL290
  • Increased fuel efficiencies
  • Increased range

For All the Right Reasons

Flying a Dash 10 Twin Commander is unequalled in its class. You’ll enjoy the performance, the safety and the savings.

Aircraft Performance

Increasing operator capabilities and margins of safety.

Unequalled in Its Class

Today’s highest performing, most desirable turboprop in its class.


A protected investment, reduces annual operating costs. Over 79% reduction in scheduled HSI/GBI maintenance.


Today’s technology and efficiencies-modular design.


Flexible intervals and multiple TBO options.

Retrofit Options

Customized to meet an operator’s current needs.


A warranty to match an operator’s overhaul choice.

Service and Support

Worldwide, on demand factory support from Twin Commander and Honeywell.

Aircraft Performance

The availability of additional horsepower at all flight levels translates into markedly improved aircraft performance in virtually all flight missions from sea level to cruise altitudes. The ability to climb faster to more fuel efficient altitudes provides an additional benefit on even short stage lengths that might have formerly dictated lower cruise altitudes

Speed: 300+ KTAS
Climb: 717.5 shaft horsepower to 16,000 feet. 3,500+ fpm through 20,000 feet.

Unequalled in its Class

Aircraft Performance Flight Test Data
Flight Test Data (690A) TPE331-5 TPE331-10T
Thermodynamic Shaft Horsepower 840 minimum 1,000 minimum
Flat Rate Torque To 6,000 ft 16,000 ft
Cruise Speed 276 KTAS 300+ KTAS
(ISA, 9,000 lb, 96%, 20,000 ft)

Unequalled in its class measured against other turboprops in its class, -10T powered Twin Commanders are unrivaled in overall speed, climb and operating costs.

Flight Test Data Flight Test Data Flight Test Data Flight Test Data
Honeywell TPE 331-10T Honeywell TPE 331-8 Pratt & Whitney PT6A-21 Pratt & Whitney PT6A-135
Shaft HP 1,000 625 550 620
Common TBO (Hrs) 5,000 3,000 2,706 2,940
Takeoff Perform SL ISA BFL (ft) 1,833 2,465 2,706 2,940
Max Range (N-Miles) (NBAA IFR Reserves) 1,424 1,566 1,120 1,282
Climb (SL ISA MTOW) Normal (FPM) 2,824 2,435 2,003 1,750
Engine Out (FPM) 1,003 715 554 470
Normal Cruise TAS 300+ 287 240 255


Increased Aircraft Value

An investment in the -10T conversion immediately translates into higher market value for Turbo Commander aircraft.

Reduced Hot Section Costs

Extended major inspection intervals reduce maintenance.

Improved Fuel Efficiencies

The -10T has shown up to 7% overall reduced fuel burn over -5.

2 Year Warranty On Turbine Components

Honeywell warranties are designed to meet your needs.

Factory Backed Program

A program backed by the engine and aircraft manufacturer guarantees maximum protection of your investment.

High Power Engine Design

TPE 331 -10T power on the 690 series Commander Aircraft means responsive, reliable flying. A geared propeller driven by a single-shaft power section utilizing dual centrifugal compressors and three axial turbines allows for a compact, low weight, and high power design.

High Technology Cooled Turbine Components

Effective cooling increases component life and reliability.

ITT Replaced by EGT

By virtue of replacing the ITT with an EGT system, -10Ts offer cost benefits through improved reliability.

Improved Thermodynamics

Due to its high thermodynamic rating, -10T engines will operate at less than 72% of rated power at full throttle operation.


The -10T’s modular hot section components and factory-initiated enhancement programs result in lower maintenance costs. Additionally, -10T operators can count on reduced downtime by utilizing Honeywell & Twin Commander Aircraft LLC’s Factory Authorized Service Centers.

Flexible Major Maintenance Intervals

Maintenance programs to fit an operators needs.

Factory Developed and Supported Aircraft STC

With over 170 conversions worldwide, the -10T powered Twin Commander is a proven design.

Retrofit Options

The TPE331 -10T conversion program allows for two retrofit options, providing choices in converting Twin Commander aircraft.

Option 1

Overhaul and Modifications

* Overhaul and Major Inspection Interval Options

Option A Option B**
Hot Section 1,800 hrs. 2,500 hrs.
Hot Section & Gearbox 3,600 hrs.
Overhaul 5,400 hrs. 5,000 hrs.

Option 2

Engine Continued Time Modification

* Overhaul and Major Inspection Interval Options

Option A Option B**
Hot Section 1,800 hrs. 2,500 hrs.
Hot Section & Gearbox 3,600 hrs.
Overhaul 5,400 hrs. 5,000 hrs.

* Desired overhaul option must be declared at the time of modification to allow for the appropriate log book entries to be accomplished.
** Greatest cost reductions

Warranty Details

* Honeywell offers warranty options for -10T conversions.

Overhaul / Conversion

Twenty-four months from date of shipment or twelve months from date of initial operation whichever occurs first for defects in material and workmanship. Additionally, the turbine section will be covered for twenty-four months from the date of initial operation.

Continued Time / Conversion Warranty

Twelve months from date of initial operation on power section and gearbox for defects in material and workmanship; thirty days from initial operation on line replacement items. Additionally, the turbine section will be covered for twenty-four months from date of initial operation.


* Refer to Honeywell Engines Warranties for detail as applicable. Would you like to receive more information on the Dash 10 Conversion? Contact a Factory Authorized Twin Commander Service Center.