Both of the major commercial turboprop manufacturers remain firm in their intentions to add larger aircraft to their product ranges. However, neither is yet ready to commit to a timeframe, with the demands of other programmes occupying precious resources.
"In terms of size we're focusing on the sub-100-seat, 90-plus market, where there's more and more potential requirement," confirms John Moore, senior vice-president of commercial at ATR, the EADS-Alenia joint venture that manufactures the 50-seat ATR 42-500 and 70-seat ATR 72-500.
New -600 series versions of these aircraft are due to enter service in 2011, equipped with a new Thales all-glass cockpit and higher-thrust engines in the shape of Pratt & Whitney Canada's PW127M. "Right now we're involved in developing and certifying the -600 series," says Moore. The first flight test of a -600 series aircraft is due this month.
As far as 90- to 100-seat turboprops are concerned, ATR is at "a fairly early stage", adds Moore. In June 2008 ATR chief executive Stéphane Mayer told Flight International that service entry was targeted for "the second half of the next decade", with the company having accelerated the "pre-study" phase.
Mayer envisaged a new aircraft family with at least two members at each end of the 70- to 98-seat spectrum. A 50-seater was also under evaluation. "If there is market, we prefer to propose three," he said.
"The question is whether we want to stay in the [50-seat] market and if there is a market or a business case." Although ATR's new turboprop family has not been named, Mayer made a reference to "the -900".
A larger turboprop is also in the thinking of ATR's Canadian rival Bombardier Aerospace, manufacturer of the Q series. In March, Bombardier commercial aircraft president Gary Scott affirmed that 2013-14 was "the sort of time period we're looking at today" for a stretched version of its 78-seat Q400 turboprop, implying a service entry well ahead of that of the next-generation ATR aircraft.
The putative new Bombardier turboprop has been dubbed the Q400X.
Norwegian regional carrier Widerøe took delivery of Bombardier's first Q400 NextGen in May. "The Q400 which we're currently producing is the first plane in the next generation," says Peter Bjarnason, manager of programme planning, development and customer requirements at Bombardier. The Q400, which entered service in 2000, has amassed close to 350 orders, of which more than 230 have been filled.
"A 90-seat turboprop should have fantastic seat-mile costs, particularly for short routes," says Richard Aboulafia, vice-president of analysis at the Teal Group. "The problem is on the supply side. Those prop makers are relatively neglected parts of larger parent corporations with higher priorities." ATR's parent EADS is preoccupied with development of the Airbus A350 XWB, while Bombardier Aerospace has been pouring resources into development of the CSeries small airliner, set to enter into service in the second half of 2013.
However, investment in larger turboprops would be "a very useful diversion of resources", adds Aboulafia. "They will almost certainly find the money eventually."
The manufacturer's latest figures show ATR has sold 985 aircraft over the life of the ATR 42/72 programme. "We should hit 1,000 sales this year," says Moore. He attributes ATR's success to the aircraft's structural efficiency, payload-to-weight ratio and fuel performance. "We just continue to focus on those main features and characteristics," he adds. "Our view is that it's going to come from the engine manufacturers and engine developments."
An efficiency improvement in the order of 20% would be required for a new aircraft programme to become viable. "It's better that we make a major step forward to justify it, otherwise you're competing with the existing products on the market," says Moore.
The sudden resurgence of the turboprop market, mid-decade, can be viewed as a product of spiking fuel prices. Yet Moore is confident that the health of the market can survive the more recent, downward fuel-price trend. "The general trend over time is upwards," he asserts. The enhanced comfort of modern turboprops further boosts their prospects, he adds. "I don't think [a turboprop] is going to be now viewed as much of a sacrifice compared with putting a smaller regional jet on many of these routes - it's a comparable product."
The launch of a larger family would fit with a broader trend in turboprop sizes. "There's just a general trend [for] the average capacity of the aircraft to increase," notes Moore. "That's due to growth in the markets and economic efficiencies. You don't have any more 19- and 30-seat aircraft produced. ATR is the last producer of a 50-seat aircraft, the ATR 42, which still sells reasonably well, but the bulk of our sales is in the 70-seat category. That trend seems to be continuing."
Engines will be "the real differentiator" for the next generation of turboprops, ATR's head of marketing Mario Formica told Flight International in November. "We consider that in the next 10 years, the regional market needs step-change technology: evolutionary technology, not revolutionary technology," he said, ruling out a stretch of the ATR 72, which could not achieve the required 30-40% cut in operating costs on short-haul sectors (compared with regional jets of similar capacity). "We cannot wait until 2020 or 2025," he added. "We [have] specific requirements that we have clearly communicated to the engine manufacturers."
These include a 20% reduction in specific fuel consumption, a higher power-to-weight ratio, better fuel flow, lower emissions, and noise levels that fall below International Civil Aviation Organisation Stage 4 limits by "good margins". Of vital importance is integration between the engine and propeller manufacturers from an early stage, facilitating optimisation of the gearbox and nacelle, as well as reduced drag, weight and line-replaceable unit count.
In December 2006 Pratt & Whitney Canada revealed it would invest C$1.5 billion ($1.3 billion) in R&D over five years. An additional C$360 million investment was announced in October. P&WC's engines power not just the ATR's turboprops, but those of Bombardier.
Aboulafia suggests that "propulsion technology has been taking a back seat to jets for years and is only now starting to get going again". Future turboprops might be powered by versions of P&WC's PW150 or PW180, or by a GE engine, he speculates. "One of the big variables in the propulsion business might be GE returning to the market, but if they do return it will be with a version of something they've had in the pipeline for years now - probably some kind of GE38 derivative."
As to whether future turboprops might embrace radical new design concepts, Aboulafia is sceptical. "The appeal of turboprops lies in their innate conservatism, using an off-the-shelf design concept that emphasises costs rather than performance."
ATR has forecast demand for 1,060 turboprops in the 80- to 100-seat category over the next 20 years, while Bombardier predicts a market for 2,050 turboprops in the much broader 60- to 99-seat category. The Franco-Italian joint venture's figure for the 61- to 90-seat category is 2,360 aircraft.
However, Aboulafia identifies competing trends that create some uncertainty about the turboprop market's prospects. "On the one hand, you do get much better seat-mile costs with a large turboprop; on the other hand, it's still all about frequency and supporting hubs at a time of shrinking traffic, which seems to argue for a return to smaller aircraft," he says.
The recent history of the turboprop market has been one of ebbs and flows. Aboulafia notes the significance of Continental Express's decision to launch Q400 services from Newark Liberty International airport in early 2008. "It was a huge event," he recalls, adding that the turboprop market has since "stalled out, probably due to oil getting cheap again. But I could easily see it being revived, possibly by new equipment stimulating the market."