ANALYSIS: Embraer quietly unveils improved E-Jet with American Airlines order

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New battle lines have quietly been drawn in the resurgent competition between Bombardier and Embraer ahead of an anticipated surge of regional jet orders.

Five years after Bombardier unveiled the CRJ NextGen series, Embraer now confirms it is preparing to rollout a similar aerodynamic makeover of the current E-Jet family. The mid-life upgrade of the E-Jet design has been anticipated, but its arrival was over-shadowed by Embraer's ongoing preparations to launch development of a second-generation E-Jet later this year.

Several airlines, however, are already well-briefed on the make-over planned for the current E-Jet. A concept for an "Embraer 175+", featuring a roughly 5% fuel burn reduction, was first disclosed - but not publicly explained - in October as part of an ultimately unsuccessful campaign by Embraer to win an order from Delta Air Lines. Instead, Delta selected the Bombardier CRJ900 for a 40-aircraft order that launched the long-awaited re-fleeting of the US regional jet fleet.

Embraer kept refining its E-Jet improvement programme despite the setback. The E-175+ nomenclature was dropped, perhaps to avoid creating confusion in the market with the second-generation E-Jet programme. It is again simply called the E-Jet, with improvements.

Embraer declined requests to provide the details of those improvements until very recently, and following a critical vote of confidence from a major customer.

Last month, American Airlines announced ordering 47 E-175s with the improved configuration. Both the American and Delta contracts served to immediately stabilize the order backlogs of both regional jet manufacturers, but they are also merely a taste of larger deals to come.

Last May, Bombardier and Embraer predicted there could be as many as five major regional jet orders involving more than 400 aircraft by US carriers. So far, only two orders in the US market have been announced involving up to 164 aircraft, including options.

For Embraer, winning more of these orders is essential for bridging a five-year gap until the second-generation E-Jet arrives in 2018, featuring new Pratt & Whitney PW1700 and PW1900 engines, new wings and a 15% improvement in fuel efficiency.

With so much still at stake, Embraer is making a new push in the market and describing the design changes that American Airlines found so compelling.

As the launch customer, American Airlines' regional partner Republic Airways will be the first to receive the E-175 with the improved features in 2014.

This new version of the E-Jet adds a redesigned pair of winglets, a 2.7m (8.83ft)- longer wingspan and various smaller improvements to reduce fuel consumption by 3.5% to 5.5%, depending on which of the four E-Jet models is ordered, Embraer says.

Embraer describes the update package as apart of a "long-term strategy of continuously improving the E-Jet family", says Claudio Camelier, vice-president of market intelligence for the Brazilian airframer's Commercial Aviation division.

It will arrive a decade after the first E-170 was introduced with LOT Polish Airlines in March 2004, the first of more than 900 such deliveries over nine years.

The original E-170/190 proved a formidable competitor to the Bombardier CRJ700/900.

In 2008, Bombardier responded by launching the CRJ NextGen, leveraging the development of the CRJ1000 to roll back aerodynamic and interior improvements into the CRJ700 and CRJ900 series. The improvements also included a set of redesigned and fuel-burn reducing winglets. The CRJ NextGen family also included various "aerodynamic clean-ups" on the fuselage and the wings, as well as a major increase in the duration between basic maintenance intervals.

Five years later, it is now Embraer's turn to roll-out a package of similar improvements with undoubtedly the same goal: keeping its product relevant in a market that is only becoming more competitive, especially with the Mitsubishi MRJ on track to enter service in the third quarter of 2015.

Aircraft makers are always looking to find new ways to improve the fuel efficiency of their products, despite the limitations imposed by the mostly fixed geometry of the original airframe.

To make meaningful improvements, the trend among manufacturers for the past decade is to look first to the outboard sections of the wings. This is where a standard aircraft wing is least efficient at generating lift, a rare area of a lack of complete aerodynamic optimization on a modern aircraft.

By simply adding a pair of winglets, airframers can simultaneously improve the lift efficiency of the outboard section of the wing and reduce the induced drag produced by any lift-generating surface, says Leandro Laia, Embraer's vice-president of programmes in the Commercial Aviation division.

Embraer introduced the E-Jet family with a first-generation winglet. However, it found that a substantial redesign could achieve significant fuel savings, accounting for roughly one-third of the 5.5% fuel burn reduction on the improved E-175, Laia says.

The redesign lowers the cant of the winglet from a near-90° angle on the original E-Jet to about a 60° angle. It also roughly doubles the length of the flattened winglet, with the result of increasing the wingspan to 28.7m from 26m.

"It provides some additional lift," Laia says. "But the main objectiveis to reduce induced drag of the wing, which is that portion of drag that exists because the wing generates lift. This new design we are developing compared to the current one gives a significant benefit in terms of drag reduction and there is a significant benefit in terms of fuel burn per flight."

In aerodynamics, of course, designers make few, if any, changes that have only a positive outcome. For every desired result, there is some inescapable trade-off, and the challenge for the designer is to find the right balance.

Embraer's new winglet provides better aerodynamic characteristics, but at the cost of two negative effects: a weight increase on the overall wing, and a longer wingspan that could reduce access to a small number of airport gates.

Embraer considered these negative changes and in consultation with their customers determined that the benefits out-weighed the negatives, Laia says.

Although the new winglet is available for new aircraft, the internal structural changes required inside the wing means it will not be a feasible option to retrofit on the existing E-Jet fleet, Laia says.

Embraer has already inducted the new winglet design in subsonic and transonic wind-tunnel tests. A flight test phase to validate the wind-tunnel data is scheduled to begin by mid-year, Laia says.

The winglets are the only new aerodynamic feature that is not available as a retrofit option on the current E-Jet fleet. A package of aerodynamic improvements is already available on new production aircraft and as a retrofit. These include steps to mitigate the drag caused by gaps in the horizontal tail area, the rain deflector, the ram air door and the wheel fairing. Embraer also has optimised the environmental control system.

A second package of aerodynamic tweaks will be introduced with the E-175 equipped with the redesigned winglets next year. These reduce the drag caused by the shape of the inlet for the auxiliary power unit and the anti-collision beacon.

In an industry with products delivered at near-peak efficiency levels, such aerodynamic changes may seem modest but are gratefully received by airlines and lessors alike.

Indeed, Bombardier redesigned the original CRJ-series aircraft with an almost identical list of improvements when the NextGen series was introduced in 2008. Not surprisingly, perhaps, Bombardier remains confident in the competitiveness of the CRJ NextGen compared with the improved E-Jets.

"We're a couple years ahead of what Embraer's doing now," says Ben Boehm, Bombardier's vice-president of business development and strategy.

While Embraer predicts a 3.5-5.5% improvement across the E-Jet series compared with its original design, Bombardier claimed an improvement of up to 4% on the NextGen CRJ-series versus the baseline CRJ.

Moreover, Bombardier can always claim an inherent advantage on fuel efficiency, Boehm says. That is because of Embraer's design philosophy with the E-Jet series emphasized cabin comfort. The original E-Jet cabins are longer, wider and taller than the equivalent CRJ NextGen models, and Embraer is making no interior changes on the improved version. The result in the 70-seat class is a heavier airframe. The basic operating weight of the E-170 is 6.63% more than the CRJ700 NextGen.

"Even if they could make their aerodynamics just as good as ours, we're still lighter and we still burn less fuel," Boehm says.

Embraer counters that although the E-170 is heavier, it contains more seats in a comparable cabin lay-out. That means it can be more fuel efficient on a per-seat basis than the CRJ700 NextGen, says Camelier. The weight of the E-175, however, is almost identical to its most direct competitor -- the CRJ900 NextGen, he adds.

Bombardier still believes its advantage can carry over even into Embraer's second-generation E-Jet, which will not enter the market until 2018. That E-Jet will have redesigned airfoils and new P&W engines designed to be significantly more efficient than the General Electric CF34s powering both the current E-Jet and CRJ family.

With its commercial aviation segment focused on delivering the CSeries small narrowbody, Bombardier has no plans to launch a further re-fresh of the CRJ NextGen or new regional jet airframe to compete with the second-generation E-Jet and MRJ.

Moreover, Boehm argues that the existing CRJ1000 NextGen will be able to compete with the second-generation E-Jet family.

"Even with all those [second-generation] changes, we'll still have an advantage, especially the CRJ1000," Boehm says.

Bombardier has ruled out the re-engining option for the CRJ, despite the strategy being embraced by Airbus, Boeing and Embraer. The CSeries was launched before Airbus and Boeing decided to re-engine their single-aisle products rather than launch an all-new airframe.

"We don't believe in re-engining airplanes," Boehm says. "Optimisation of an airplane starts at a pre-natal age."

That means the competitive landscape for the large regional jet market is now officially set for the remainder of the decade. Barring some unforeseen announcement, the competition will be split initially between the improved E-Jet and the CRJ NextGen, and then between the MRJ, second-generation E-Jet and, still, the CRJ NextGen.

In the near-term, Bombardier may claim a advantage in fuel efficiency, if not always in cabin comfort. But Embraer will not be without other favourable comparisons on the improved E-Jet.

Maintenance cost has been a constant back-and-forth battle between the two manufacturers. The CRJ700 was introduced in 2001 with a 4,000h interval between basic maintenance checks. Embraer delivered the E-170 in 2004 with a 6,000h interval, which Bombardier matched with the CRJ NextGen.

Airframers are always seeking an advantage, and Embraer has now made the next move. The improved E-Jet, says Embraer's Camelier, will enter service with a 7,500h interval between maintenance checks.

[Updated to include Embraer's response to Bombardier statements about the weight advantage of the CRJ NextGen.]