With its mix of brand-new, five-axis CNC equipment and hand-cranked milling machines – some dating from just after the Second World War – a tour of GE Aviation’s Prague facility highlights the journey the one-time Walter Aircraft Engines has been on since becoming the US business’s first overseas fully integrated manufacturing operation.
GE acquired the ailing Czech engine-maker and its M601 turboprop engine – which powers the Let Aircraft Industries L-410 among others – in 2008, and moved to the current factory next to the city’s Letňany airport in 2010. Since then, GE has invested heavily in its central European subsidiary, introducing modern machinery and US quality control processes.
It updated and relaunched the venerable M601 as the H family, and earlier this year came the expected confirmation that GE Aviation Prague had been chosen as design and production hub for the new advanced turboprop (ATP) engine, intended to take on the ubiquitous Pratt & Whitney Canada PT6A.
The 1,300shp (956kW) GE93 is set to power the still-to-launch Textron Aviation turboprop single expected to enter service around the turn of the decade. The Wichita-based manufacturer confirmed the existence of the aircraft in July last year and GE’s involvement in the programme in November.
GE’s decision was a huge fillip for a Czech aerospace sector still to recover after the Soviet Union’s collapse closed a massive military and commercial market for manufacturers such as Aero Vodochody and Let Kunovice. Industries that once employed tens of thousands of engineers and blue-collar workers were left scrambling for new customers and investment.
While both these firms have survived in a different guise – Aero Vodochody reinventing itself as an aerostructures specialist, and the now Russian-owned Let Aircraft Industries relaunching the L-410 – GE’s move secures the future of the country’s former propulsion champion as a “centre of excellence”, providing power for a new generation of turboprops.
GE is not announcing a timetable for the new engine family – Textron is expected to shed more light on its programme in the coming weeks. However, the project is “progressing on schedule”, says Norm Baker, president and managing executive for business and general aviation turboprops at GE Aviation.
“We are in heavy planning for the start-up of components, but we are not turning any parts yet,” he says. “We expect to start building the first test engines next year.” While GE is in discussions with the authorities over opening a new factory, production of the engine will begin at the current site. GE has a lease until the mid-2020s and there is room to expand.
In the meantime, manufacturing the 750-850shp H80 and its H75 and H85 derivatives, together with servicing and upgrading legacy M601s, is the main activity at the Letňany site. Based in an old, but fully refurbished factory, and near several other aerospace sites including Latécoère and Avia Propeller, some 400 staff are employed there.
The plant is unique to GE in that it is vertically integrated – the entire process, from milling components, through sub-assembly and final assembly, testing and customer dispatch, is under one roof. “We have a lot of capabilities. We are the only site outside the US that is fully EASA-certificated for design and manufacturing,” says operations leader Jason Kuiper.
The factory produces some 800 components for the H series engine, over half the entire part numbers. “We do screws up to parts that take eight months to make,” says Kuiper, “In fact, all the engine’s critical parts are made here except the combustor components and reduction gearbox, which come from the supply chain.”
It is a raw-material-to-finished-product process that is not without its trials, admits Kuiper, a fluent Czech speaker who learned the language while serving in the US military. He describes the factory as a “microcosm” of what would be a manufacturing chain spanning several sites for a larger GE engine. “I see it as a challenge but also a whole lot of fun.”
The H80, which received European Aviation Safety Agency approval in 2011, was the first GE engine to be developed outside the USA and to get its initial certification from the European authority. The main changes to the four-decade-old M601 are blisks replacing bladed discs, new blades and the use of lighter titanium instead of stainless steel.
As well as the L-410 and its L-410NG successor, the H series powers the Ayres Thrush 510G crop-sprayer and the new Nextant King Air G90XT, a re-engined version of the King Air C90, currently in flight testing. Other applications are the single-engined Primus 150 from China’s CAIGA and the Rysachok utility twin produced by Russia’s Technoavia.
Baker is reluctant to disclose how many new engines the Prague site is building, but it is clear that the economic crisis in Russia – a major market for the L-410 – has impacted sales. “We are geared up for 100 a year, but the Russian and the agricultural markets have been soft,” he says. “We expect to be ramping up again soon.”
However, including the overhaul of in-service engines, Baker says GE is handling “200-plus” engines a year. With “tons” of M601s in operation, the maintenance, repair and overhaul market is “growing”, he says. The H80 engine entered service in early 2013 on the Thrush, and some of the earliest examples will come back for overhaul this year, he says.
The company has also “turned strongly to the STC [supplemental type certificate] market”, says Baker. A retrofittable upgrade for the Thrush will be ready to install next year, and the variant is likely to be offered as standard on new-build aircraft. “We’ll let the market decide, but we expect it to move that way fairly quickly,” he says.
GE has also begun certification flights on a version of the engine that incorporates an electric control system. “It’s not quite like FADEC [full authority digital engine control], but it reduces the pilot’s workload and enhances the pleasure of flying,” says Baker. “The pilot is no longer trying to set torques and propeller speeds.”
GE has begun hiring manufacturing and engineering personnel for the ATP project. “There’s a flurry of activity for HR,” says Baker. With the Czech Republic’s good education system, low living costs and strong aerospace heritage, recruiting the right skills locally has not been difficult, although some staff have been lured from sister businesses in Italy and Poland.
Kuiper admits to the “odd skeleton we have had to tackle” in changing the culture of a workforce used to the hands-on production methods of Walter. Some were excellent craftsmen, says Kuiper: “The expression is that they had golden hands.” However, they were not necessarily used to the rigour of record keeping and quality control demanded by GE.
However, the advantages of having a workforce steeped in product knowledge are invaluable, especially when almost the entire programme is handled in house. “We have some guys here who were around at the certification of the M601 in 1975,” he says. “Others have retired but come back one or two days a week as consultants to share their expertise.”
That Walter heritage – combined with GE’s vast experience in industrial processes – will help create a virtuous circle as the new engine comes on stream, maintains Baker. “A lot of experience will go into the ATP,” he says. “But a lot of learning will also come back from the ATP to feed into what we are doing on the H series.”
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Source: Flight International