MRO Management

Maintaining a power dynasty: Two generations of Airbus A320

Airbus A320
photo_camera People at Work Bldg 220 DURR Line MT, Ct 2/3/2016

Aviation Business News reports on the maintenance of two generations of powerplant for two generations of Airbus A320.

Pratt & Whitney’s PW1100G-JM engine for the Airbus A320neo family has had its fair share of headlines through the early part of 2018. The focus of those reports was a problem relating to a knife edge seal on the high pressure compressor (HPC) aft hub in one particular batch of engines.

This caused some of the aircraft they powered to be grounded. The successor to the IAE V2500 in powering the Airbus single-aisle family has had a mixed entry into service, meeting many of the specifications the OEM set for itself, but having some teething problems too. Modifications had to be made.

So before discussing the maintenance of the PW1100G-JM and its predecessor, the matter of those modifications has to be addressed. In February, the company released a revised configuration to rectify the problem. Joe Sylvestro, vice president, aftermarket operations for Pratt & Whitney, explains the background to the situation and what the modification work has entailed.

“We implemented an engineering change in mid-2017 with the intent to improve long-life durability for the knife edge seal in the high pressure compressor. Instead, as you know, it had the opposite effect, which we quickly identified and addressed. There was no original ‘failing’ that we were addressing,” Sylvestro remarks.

“The modification, which was certified within a week of submitting to the appropriate regulators, is based on a prior design with slight modifications,” he continues. “We were able to immediately implement this modified design into new production and overhauls, and shipped the first engine with this certified configuration on 26 February. We have received a number of the 55 engines back from Airbus that were awaiting installation and have started modifying and returning them to Airbus.”

Moving on to the MRO work, while preparing for the whole PW1000G family to enter service, Pratt & Whitney built its portfolio of aftermarket service for the engines, suitably branded PureSolutions.

At MRO Americas 2017, however, the EngineWise portfolio of services – which includes all of the services the company currently offers, including those for the [PW1000G] Geared Turbofan (GTF) engine family – was introduced with some fanfare. As a result, according to Sylvestro, the PureSolutions brand “will sunset” in favour of EngineWise.

While Fleet Management Programs (FMPs), engine overhaul services and material solutions led the launch of the EngineWise portfolio, new services continue to be added, as Sylvestro confirms.

One of the solutions added at launch was Advanced Diagnostics & Engine Management (ADEM) which helps operators monitor and maintain their engine fleets better.

Aircraft engine

“EngineWise is about simplifying our services portfolio and introducing new offerings to support customers’ evolving needs,” he asserts. “We have established a dedicated organisation focused on developing new solutions with customers across the entire life cycle, covering both mature engines and new products like the GTF engine.

“Most recently, we announced new data analytics capabilities for V2500 engines as a result of achieving a supplemental type certificate (STC) for the Airbus A321 aircraft powered by the V2500. With this STC, we are able to expand our current EngineWise data analytics capabilities for our customers currently flying the A321 and be more agile and flexible than ever before,” Sylvestro elaborates.

“Additionally, Pratt & Whitney will be better able to develop aftermarket services catered to customer’s needs and respond faster and better to incidents in the field utilising the eFAST data ecosystem on these aircraft,” he notes.

Currently eFAST is only available for the PW1500G engines which power the Bombardier C Series but Sylvestro says he expects this technology to be extended to the PW1100G-JM in the future. “With regard to benefits, the GTF engine incorporates 40 per cent more sensors than the V2500 engine, and can generate approximately 4 million data points per engine per flight, enabling significant improvements in addressing unplanned maintenance,” he emphasises.

As with any engine programme, the V2500 has had a number of iterations, each of which has improved performance. The first upgrade, which entered service in October 2008, was the SelectOne configuration.

This brought improvements in the high pressure compressor (3D aerofoils and an elliptical leading edge), the low pressure turbine and high pressure turbine (better aerofoil cooling, advanced sealing, new materials and coatings). The results included a 1 per cent additional fuel burn saving, a time-on-wing improvement of up to 20 per cent, a greater EGT margin and fewer shop visits.

Then came the SelectTwo upgrade, which was certified in 2014 and entered service early the following year. Nowadays the V2500 SelectTwo is “the bill of material for new production deliveries”. “Approximately one quarter of the V2500-A5 engines in the fleet are SelectTwo configuration, 35 per cent are SelectOne and 40 per cent are the classic A5 configuration,” Sylvestro reports.

“To upgrade to SelectTwo from the SelectOne configuration, operators must deploy a software change, which optimises the fuel flow consumption during descent and taxi and which generates a 0.6 per cent fuel burn improvement for a 500 nm mission. The upgrade from SelectOne to SelectTwo can be done on wing,” he adds.

Maintaining Airbus A320 engines

V-Services was IAE’s suite of aftermarket services for the V2500, but as with PureSolutions, these are also now being incorporated into the ever-expanding smorgasbord of EngineWise options. Sylvestro reports that the number of customers for these services is on a steady upswing.

“Today, there are about 60 V2500 engine customers that operate or manage engines under one of several types of long-term maintenance agreements available under our EngineWise services. That represents over 65 per cent of the V2500-A5 engine fleet and growth from about 55 per cent in 2013,” he confirms.

Back in June 2012, Pratt & Whitney bought Rolls-Royce’s share of IAE. However, the UK engine maker is still responsible for the manufacture of high-pressure compressors, fan blades and discs. It also has a hand in engineering support and final assembly.

“The restructure of the IAE joint venture in 2012, with Rolls-Royce shares being dispersed, had no impact on long-term maintenance agreements,” says Sylvestro. “As part of the restructure, the Rolls-Royce overhaul shop will continue to provide services as part of the IAE network for some time. Growth since 2013 in IAE coverage of the V2500 fleet shows the strength of this MRO portfolio.”

Rolls-Royce’s services research manager, civil aerospace, Alistair Forbes, confirms that his company is still very much involved in supporting the V2500 fleet. “As part of the IAE consortium, Rolls-Royce performed MRO on V2500 engines at its facility in East Kilbride in Scotland. The vast majority of these overhauls were performed on engines covered by IAE’s V-Services aftermarket support agreement,” he remarks.

“Although Rolls-Royce withdrew from IAE in 2012, it continues to overhaul V2500s in Scotland (now at Rolls-Royce’s new Inchinnan facility a few miles from East Kilbride). These V2500 shop visits are performed either under legacy V-Services agreements or direct contracts with individual airlines,” Forbes elaborates. “Inchinnan caters for engines owned by airlines all around the world, not just from Europe and continues to win work from IAE on the basis of highly competitive time cost and quality criteria.”

MTU Aero Engines, Pratt & Whitney’s ongoing partner in both the V2500 and the PW1100G-JM programmes, also provides MRO support on these engines to airlines through its MTU Maintenance subsidiary. Thomas Schulz, Director Programs of MTU Maintenance is confident that there is plenty of business out there on the V2500.

“In 2017, MTU Maintenance completed around over 300 repair and overhaul shop visits for 34 per cent of the world’s V2500 fleet – making it the number one provider of V2500 MRO services worldwide,” Schulz stresses. “This has increased continually from around 270 in 2012. We expect to see a higher number of shop visits this year, thanks to the introduction of the V2500-A5 line in Canada in late 2017, as well as the extension of capacity in Zhuhai.

Maintaining Airbus A320

“Shop visits are not expected to peak at over 1,000 shop visits per annum on this engine family until the early 2020s – as such MTU Maintenance is currently investing in its capacity,” he continues. “For instance, we will further invest in our Zhuhai facility: its capacity of 300 shop visits per year is to be expanded by another 50 per cent again within the coming years. This is after our expansion – by 50 per cent at the time – in 2012.”

In addition the expanded facilities, MTU Maintenance’s growth in V2500 work has been supported by new repair techniques and processes that the company has developed. “Generally speaking, repairing parts is an extremely good way of reducing material costs for customers,” Schulz indicates. “Furthermore, MTU Maintenance performs around 80 per cent of repairs in-house, meaning that not only can turnaround times be improved through simpler logistics, but it also enables us to control processes and quality.

“We introduced a number of repairs and processes for the V2500 during the last year. For instance, the Select One HPT (high-pressure turbine) Vane 2, the Select One HPT Blade 2 and the Ceral 10 green coating for LPT (low-pressure turbine) vanes,” Schulz confirms.

“Furthermore, we offer [a range of] high-tech proprietary repairs for V2500 engines. These repairs have been developed by MTU’s expert engineers and significantly reduce material costs and scrap rates, increase time-on-wing and improve the SFC (specific fuel consumption) of engines,” he states.

“For instance, our CMAS (calcium–magnesium–aluminium–silicon oxide) resistant thermal barrier coating and our ER-COateco (erosion-resistant coating for HPC aerofoils) can be used to considerably increase on-wing times in harsh operating environments.”

Quite naturally, Pratt & Whitney has also been working on developing new repair techniques and processes for the V2500 in the past 12 months. Sylvestro outlines what has been achieved and the benefits they bring to airline customers.

“One of our EngineWise services available for V2500 engines under Fleet Hour Agreement support is mobile support. It is designed for engine maintenance between scheduled overhaul visits,” he remarks. “As part of mobile support, Pratt & Whitney is performing on-wing and near-wing light maintenance such as quick-turn repairs, service bulletin incorporation and component replacement.

“Airlines benefit by alleviating operational disruption, reducing repair costs and minimising lease engine requirements. Pratt & Whitney has teamed with Lufthansa Technik to perform V2500 and PW1100G-JM and PW1500G on-wing and near-wing light maintenance at numerous locations around the globe.

Airbus A320 engine

While Sylvestro is not in a position to share the uptake figures – the number of engines under this mobile services agreement – he makes an important observation. “With more than 7,000 V2500 engines delivered and the number of GTF engines in service continuing to climb, we are investing in smart, straightforward mobile services through our EngineWise service brand that help operators more quickly address unscheduled engine maintenance while optimising fleet readiness,” he declares.

Sylvestro moves on to other service developments. “For engine maintenance between scheduled overhaul visits, we are performing quick-turn surgical strikes to replace engine modules or components that our customers need, while maintaining our high-quality and high-performing engines,” he adds.

“We are continuously investing in our repair capabilities to help drive down our customer’s operating cost. For example, we are working on expanding reparability on parts such as compressor variable stator vanes. From our initial sampling, scrap rates are projected to be reduced by around 20 per cent-30 per cent resulting in reduced maintenance cost,” the VP reports.

For MRO work on both the V2500 and the PW1100G-JM, the OEM has continued – like its partner MTU – to expand its the global support network, both in terms of the service centres it owns and its recognised service facilities.

Most recently, at the MRO Americas conference and exhibition in OR, Florida, the company announced five more repair suppliers who will support the PW1100G-JM engine. Turbine Controls, StandardAero, TWIN MRO, ACMT and Lewis & Saunders will join other GTF MRO providers.

The GTF MRO network already had the three partners on the PW1100G-JM (Pratt & Whitney, MTU Aero Engines, Japanese Aero Engines Corporation) along with Lufthansa Technik and Delta TechOps.

According to Heather Walton, senior director, Aftermarket Supply Chain at Pratt & Whitney, “This is an important milestone in repair sourcing as these are the first third-party suppliers to join the GTF engine repair network. These suppliers have had long-term relationships with Pratt & Whitney and deliver a high level of responsiveness, exactly what we are looking for to support our repair network for the GTF engine for years to come.”

“Over time, as the volume of overhauls increases, the network is expected to expand to include airlines and other MRO shops,” Sylvestro adds.

The VP also points out that the V2500 MRO network also continues to grow. “The Pratt & Whitney Shanghai Engine Center began overhauling V2500 engines in 2017. Additionally, this past December, Israel Aerospace Industries and MTU Maintenance Canada announced that they would provide MRO services on V2500 engines,” he confirms.

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