Mid life crisis

For a number of years, both manufacturers have been keen to increase the output of their aircraft and make only incremental improvements to the A320 and 737 families, taking advantage of new, lighter weight interiors and engine improvements by the GE-Snecma CFM consortium and the Rolls-Royce and Pratt & Whitney led International Aero Engines. With Airbus’s recent launch of its “sharklets” for the A320, both manufacturers now also offer fuel-saving winglets.

Boeing last year also revealed a number of minor tweaks it would make to the 737, including the new Boeing Sky interior, as well as airframe tweaks and an update to the aircraft’s CFM56 engines, which altogether would result in a two per cent improvement in fuel burn by 2011.

In the meantime, the maturity of new engine technologies, such as Pratt & Whitney’s geared turbofan technology, as well as CFM International’s commitment to launching its LEAP-X engine from 2014, there has been growing momentum for both the 737 and A320 to be re-engined.

Part of this has been coming from the new competition – particularly the 110-130 seat Bombardier CSeries. Powered by the geared Pratt & Whitney PW1000G, the aircraft has promised to deliver major reductions in fuel consumption against the competing 737-600 and A318.

But with the economic crisis and few orders forthcoming, both Airbus and Boeing had largely written off the threat that it posed to them.
That was until February when Republic Airways (which owns US carriers Frontier and Midwest, as well as a host of regional operators) placed an order for up to 80 of the 130 seat CS300s. Added to that, Brazilian manufacturer Embraer has also shown some signs that it may push into the market above the 125 seat E-195. The launch of the Comac C919, which is to be powered by the CFM LEAP-X engine will add further competition to the market, particularly for Chinese carriers.

Speculation throughout the past few years has now turned serious, with Airbus’s chief operating officer – customers John Leahy announcing earlier this year that the manufacturer has been undertaking technical studies on expanding its engine offering on the A320 Family. According to some media reports, the company was expected to present a case to offer a new generation engine offering to its board by the end of April, with the aim to launch the program at July’s Farnborough Airshow.

On the Boeing side, CEO Jim McNerney also noted in January that a study into a potential re-engining of the successful 737NG was “under active consideration from a product requirement standpoint”.

In the same month, the Seattle based airframer announced the appointment of former 787 head Mike Bair to lead a new Advanced 737 Product Development team, which is expected to examine the possibility of re-engining the 737. The team will also have responsibility for developing the roadmap for its possible successor aircraft, which is not expected to become available until 2020 at the earliest.

Both Boeing and Airbus are thought to be targeting a reduction in specific fuel consumption of up to 15 per cent from the engines compared to current generation narrowbody engines. The airframers are also likely to incorporate other aerodynamic refinements and weight savings to also help reduce fuel consumption.

Making it work

While technical feasibility studies are already underway, both Airbus and Boeing have been tight lipped about what may be involved with re-engining their narrowbodies to remain competitive out until their eventual replacement in the 2020 decade.

But both have also made it clear that re-engining is about where it will end, with no planned enhancements to avionics or anything else. “If we do it (re-engining), it will be just an engine option,” Leahy told AviationWeek in March.

Similarly, Boeing Company CEO Jim Albaugh told a group of journalists in a recent round table interview that the company would have to be disciplined to ensure that the requirements did not push the 737 into the direction of a new aircraft.

“I will do everything I can to reduce the requirements creep, so it doesn’t become an equivalent of a major change to the aircraft, and we certainly don’t want it to become a new airplane,” he said. “When we do a new airplane we want to bring the right technologies to it, which will really give us a leap over what we’ve built today.”

As such, both airframers are understood to be looking most closely at integrating some of the newer generation engines – namely CFM’s LEAP-X and Pratt & Whitney’s PW1000G – with as few changes as possible, while maintaining their respective continual improvement programs after that.

Comparatively, it appears that this will be easiest to achieve on the A320 due to its generous ground clearance. While a new engine will mean changes to the pylons and wing loading, it should theoretically be able to take a higher bypass turbofan without too many challenges.

By contrast, the 737 may face more engineering work to accommodate the new generation of engines due to its low ground clearance. Nevertheless, Boeing’s Randy Tinseth recently said that the company would look at options to modify the nose landing gear to increase the ground clearance, although it “does not want to” and “would not have to” make any changes to the main landing gear.

Both airframers are expected to launch their respective reengining programs as simple engine options, while continuing to offer the current generation aircraft alongside. Boeing previously did this with the launch of the CFM56 powered 737-300 series, which began production alongside the PW JT8D powered 737-200 during the 1980s.

The choice of engines is also expected to be a source of challenge for both manufacturers. Airbus has stated that it would prefer to be able to offer new products from its existing engine suppliers CFM and International Aero Engines for the A320. While CFM is understood to be interested in offering the LEAP-X, IAE’s two major program partners Pratt & Whitney and Rolls-Royce have not been able to come to an agreement on the right technology going forward.

Pratt & Whitney has offered to make available its geared turbofan technology for use on an IAE engine, but Rolls-Royce is said to favour utilising a three shaft engine as it has on its later Trent series engines for aircraft such as the 787 and A380. As of late March, it appeared increasingly likely that Pratt would potentially go it alone and offer a version of the PW1000G as an option against the existing IAE V2500.

Airbus may be open to this, particularly as it has been involved in extensive testing of the geared turbofan demonstrator engine since 2008 when it commenced flight trials of the engine on board an A340-500.

On the Boeing side, it appears that the LEAP-X may have the edge over the PW1000G, given CFM has been the sole supplier of engines for the 737-300/400/500 and the Next Generation series. Nevertheless, executives from Pratt have said that they would be willing to offer the PW1000G.

In an April report on possible re-engining, New York based Bernstein Research noted that Airbus would face some major internal challenges if it does indeed go ahead with offering a new engine for the A320 Family, particularly “given the demands on the A350, A380 and A400M. The company does not want to put any of these three programs at risk, which is the one factor that we think could stop an A320 re-engine decision.”

Market reaction

Should the new engine options become available from 2015 onwards, it appears that there are a number of airlines interested in potential orders.

Qatar Airways, which strongly talked up the CSeries at its launch in 2008, has expressed its interest in ordering a possible re-engined A320 to replace its current fleet of the type. Interestingly, CEO Akbar Al-Baker has labelled the concept as a “CSeries killer”, although he has also indicated that negotiations on a possible order for the CSeries are expected to continue later this year.

Recent reports also claim that British Airways has expressed an interest in re-engined narrowbodies, albeit as part of its long term fleet plans. SAS has also expressed an interest in new generation narrowbodies to replace its sizable fleet of McDonnel Douglas MD-80s, although it is also expected to be a major target for the CSeries.

In the Australasian region, the market for a re-engined narrowbody appears much smaller, with carriers Air New Zealand, Virgin Blue, Jetstar and Tiger Airways all recently placing large orders for aircraft, while Qantas still had 28 737-800s on order.

However, there are signs that Jetstar already has its eye on the next generation of narrowbodies, with the announcement in December last year that it would team with AirAsia to jointly define and purchase the next generation of aircraft to replace both airlines’ fleets of A320s.
While that is some time off, the talk of a new engine for narrowbody types is already having an impact on the current market, with Qantas announcing in February that it was already adjusting the expected residual values of its 737 fleet due to the expected launch of a new engine variant for the type.

Lessor AerCap also announced that it would not place any new aircraft orders in the short term until the details of new engines became clearer due to the risk that it put on the current 737 and A320 fleet’s residual values.

Interestingly, while the attack from smaller aircraft such as the CSeries is at the smaller end of the market, a new engine would most likely benefit the larger models in the narrowbody series, such as the A321 and 737-900 due to the additional range and efficiency it would likely give them. That could allow these aircraft to become the natural replacements for the 757-200, particularly on low density, medium haul routes.

Towards replacement

While re-engining and cabin refreshes could extend the production of the 737 and A320 out a number of years, many are still expecting work on the eventual replacements of these aircraft to eventuate some time during the next decade, although what they will be like is not sure.

“We’re looking at a clean sheet of paper airplane for 2024 that might be built out of composite, that might have unducted rotors, that might have a canard on it – we don’t know. We need to spend about another 10 years on that technology,” Leahy said at the recent Singapore Airshow.

With the 787 now soon to be certified, some believe that narrowbody aircraft will naturally follow in the 787’s footsteps and could be mainly made from advanced composites. However, Boeing’s Albaugh recently noted that composites may not be as suited to smaller aircraft. “Composites are very strong, and we have sized the composite wing of the 787 to have the strength necessary to lift the airplane, but also resist impact – hail, mechanical impacts – start scaling it down and you have to have the same thickness for a smaller airplane that you have on a bigger airplane, not because of the stresses caused by lift, it’s really the impact of hail, equipment impacting the wings, you really don’t get the efficiency scaling down right now, you get the efficiency scaling up.”

Others point to the difficulties that composite aircraft may face as a result of the more demanding flying regime of narrowbody aircraft. With a greater number of sectors, and rapid turnaround times, some analysts believe that composite narrowbodies could me more susceptible to impact damage from ground vehicles – damage which is not always as visible as in metal structures. As a result, some of the new generation aircraft, such as the CSeries and Mitsubishi Regional Jet, will be made out of advanced metals such as lithium aluminium.

There is potential that the new generation of narrowbodies may more closely resemble widebodies, with increasing interest in twin aisle concepts. During the mid 2000s, Boeing took out a patent on a twin aisle, 100 seat design which was under consideration for a 737 replacement. The idea was not a new one, with McDonnel Douglas having floated the concept with the MD-XX in the early 1990s which was to supersede the MD-80 series.

No doubt, the new generations will also take advantage of newer technologies as they mature over the next decade, particularly with the aircraft’s engines. CFM has already indicated that for the eventual replacements for the 737 and A320 that it intends to take advantage of more mature technologies, such as ceramic matrix composites, to deliver greater reductions in fuel burn. Pratt has also confirmed that it intends on developing a “second generation” geared turbofan which would be ready by the end of the decade to meet the needs of a replacement narrowbody.

Also expected to be in the mix will be unducted turbofans, which promise great reductions in fuel consumption. CFM has shown pictures of a possible unducted LEAP-X engine, while other manufacturers are also undertaking research into how to use the technology and reduce the noise produced by the unducted fans.

Farnborough and further

Come July, the eyes of the commercial aviation world will no doubt be locked firmly on the Airbus display at the Farnborough Air Show as to whether the company does indeed go ahead with a launch of a new engine option. It will then turn to Boeing to see what it is able to offer, and no doubt from there what the intentions of Bombardier and Embraer will be.

Even if these aircraft do gain new generation engines from 2015 onwards, it appears that any changes to the A320 and 737’s engines will only be a stopgap measure until the work begins in earnest on a replacement narrowbody aircraft, at which time many operators will be looking to roll over their fleet of ‘first generation’ A320s and 737NGs. As such, the bigger race between Boeing and Airbus may be towards who can design and build the next generation 100-150 seater first, and potentially take the lions’ share of the market.