Consensus is building among manufacturers and operators alike for a new 90-seat regional turboprop airliner, according to Pratt & Whitney Canada (P&WC), which is eager to press ahead with its plans for a New Generation Regional Turboprop (NGRT) engine. Both ATR and Bombardier are known to be actively considering plans for larger members of their respective turboprop families and P&WC is stepping up development work to be ready for what it believes could be a pair of program launches next year.

According to Richard Dussault, P&WC marketing vice president for regional and helicopter markets, the airframers are broadly in agreement that the target speed for the new turboprop transports would be between 300 and 325 knots. In his view, the optimum speed will likely closer to 300 knots if they are to achieve the desired goal of a 20-percent reduction in fuel burn, compared to the PW100 family of engines, first certified 30 years ago and still serving the regional airline market.

For the envisaged 5,000- to 7,000-shp engine family, P&WC is tapping technology developed by sister company Pratt & Whitney for the PW1000G geared turbofan to power the new Bombardier CSeries and Mitsubishi Regional narrowbody jetliners, such as the new Talon combustor that delivers significant reductions in nitrous oxide (NOx) emissions.

Fresh Demand

According to Dussault, fresh demand for both the ATR family of twin turboprops and Bombardier’s Q400 series is prompting both manufacturers toward a launch decision for new larger models up to a maximum capacity of 100 seats. In his view, a cruise speed of a little above 300 knots is optimum to preserve the fuel-burn advantage of turboprops over jets. In addition to conferring with the two leading airframers in the sector, the Canadian engine maker also has been in consultation with up to around 300 prospective airline operators worldwide and it believes there is sufficient interest to support the launch of new 90 seaters by both ATR and Bombardier.

“Back in 2003, there were only 24 [regional airliner] turboprops delivered at the height of jet mania,” said Dussault. “But when the price of oil went above $50 [per barrel] the economics changed completely. Turboprops consume 40 percent less fuel than jets on short segments, but jets are not standing still and this is why we need to achieve a further 20-percent reduction [in fuel burn]. I foresee a [regional airliner] market in which about 40 percent of the fleet is turboprops.”

Phase One Completed

P&WC has now completed phase one of the development work for the new turboprop, which mainly focused on testing compressor components. Earlier this year, the company shipped the first fully assembled compressor to MTU in Germany and tests of this unit to verified performance standards and load limits are almost complete.

“Certifying turboprop engines is complex work, involving the integration of the engine, the control system and the propeller before we test it in flight on a [Boeing] 747,” explained Dussault. “We’ve developed more than 37 different models of turboprop [not including the PT6 family], so we bring a low-risk option for the OEMs.”

The next task for P&WC is finalizing the exact requirements for the new engine before entering the post-contract phase of the development. This covers areas such as the amount of bleed air in the air management system, the control system architecture, as well as the engine’s electrical load and physical geometry.

Beyond that, the company would undertake the detailed design and procure hardware, with a view to conducting the first ground test within 18 months of program launch for the new aircraft. P&WC’s goal would be to achieve first flight on within 30 months and final certification within 42 months. “Everything now is about our readiness for when the market is ready for the new engine,” concluded Dussault.