Workhorse turboprops

Sales continue to outpace those of jets, based on strong economics, large cabins and flexible mission profiles.

By Stuart Lau
ATP/FE/CFII. Boeing 747/747-400, 757/767, CRJ, Saab 340

Hawker Beechcraft and its predecessors have sold more than 7000 King Air series aircraft over the past 45 years. What for many operators is the ultimate go-anywhere short-field performer is also the reigning champion of multiengine turboprops.

Sustainable flight operations require a balance between social, economic and environmental objectives. Flight department managers must select aircraft that reasonably satisfy mission requirements while passing the scrutiny of an ever vigilant finance department.

Turboprop aircraft make both economic and environmental sense and are an attractive option for regional travel up to 1000 miles. In niche utility markets they are often the only choice.

According to GAMA, the turboprop market is alive and well. During the 1st 9 months of 2012, 368 turboprop aircraft were shipped world­wide, accounting for 46% of total new turbine deliveries. Over half of those were either Cessna Caravans or Hawker Beechcraft King Air series aircraft.

Rounding out the top 5 best sellers were the Pilatus PC12NG, Daher-Socata TBM850 and Piper PA46T Meridian. In this case, the top 5 most popular aircraft represent 90% of all new turboprop deliveries. Other manufacturers deliver­ing turboprop aircraft are Pacific Aero­space, Piaggio and Quest.

Remarkably, Pratt & Whitney Canada PT6A variants powered every new turboprop aircraft delivered in 2012. For over 50 years the PT6 has been the mainstay of the business aircraft turboprop engine market—it's installed on more than 100 aircraft types. Continual im­provements have increased the PT6's reliability, efficiency and performance—power now ranges from 500 to over 1900 shp.

Honeywell and GE Aviation also offer turboprop engines to the business aviation market. Honeywell's TPE331-14GR is currently installed on the Dornier (now RUAG) Do228 NG and has been selected to power Alan Klapmeier's Kestrel K350 325-kt single. Texas Turbine has sold 45 SuperVan 900 conversions that up the Caravan's original 675-shp power to 900 shp with the TPE331-12JR.

In Aug 2007, GE Aviation purchased Czech Republic-based Walter Engines. This transaction allowed GE to enter the small turboprop market with the Walter M601. Similar in theory to the PT6A—a reverse-flow free turbine design—the M601 had an installation base of 1500 engines on 30 different aircraft types.

Building on the robust origins of the M601, GE used advanced engineering and materials to create the new H80 series. Following FAA certification in Mar 2012, GE expects to produce 70 H80 engines this year. The H80 currently powers the LET L410 UVP-E20 airliner and Thrush 510G agricultural aircraft, and is available as a retrofit on the King Air 90 through Smyrna Air Center's Power90 conversion program.

Modern turboprop aircraft have avionics similar to those installed on most business jets. All new aircraft have advanced GPS-based navigation capabilities, integrated autopilots, terrain and traffic awareness systems, and some are now equipped with a synthetic vision system (SVS).

OEM-installed avionics systems are represented by Garmin, Honeywell and Rockwell Collins. Garmin G1000 systems account for 54% of all new deliveries and are becoming popular as a retrofit option on older aircraft.

As legacy avionics systems become obsolete, retrofit programs are gaining in popularity, allowing operators to cope better with ever-evolving, more complex air traffic management systems. As an example, MLI (Moline IL)-based Elliott Aviation recently completed its 75th King Air G1000 installation, while Hawker Beechcraft Global Support has certified the Rockwell Collins Pro Line 21 on the Beech 1900D airliner and on existing King Airs.

"Green" machines

Over the past 40 years, according to IATA, the air transport industry has improved fuel efficiency by 70%. Between 2001 and 2008 alone, fuel efficiency was improved by 16%.

IATA has a 4-pillar environmental strategy to mitigate greenhouse gas emissions from aviation by improving technology (winglets and engines), operations (reduced fuel burn), infrastructure (ATC) and economic measures.

Specific range is a measure of aircraft efficiency. Expressed as nautical miles per pound of fuel used, analysis indicates that turboprops have a clear advantage over jets. (See charts at top of page.) Factoring in standard passenger configurations, normalized specific range figures point to turboprops, with their larger passenger cabins, as the clear efficiency champions.

The Piper Meridian and Pilatus PC12NG have the smallest environmental footprint of any turbine-powered business aircraft under US$8 million, carrying the most passengers the greatest distance on the least amount of fuel.

During the Great Recession of 2007–09, some charter operators witnessed a shift in customer spending habits. Recognizing the value of business aircraft, some clients continued to fly but began to "right size" their aircraft to match the mission.

As an example, M&N Aviation—a Denver CO-based Part 135 operator—often had traditional Hawker 800XP or Challenger 300 customers opt for the smaller PC12 on regional flights, sacrificing speed for less cost and more efficiency. Adding sustainability to their business and the environment, these customers reduced their spending, conserved more fuel and emitted fewer harmful greenhouse gases.


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