Recent changes to the proposed Airbus A350 have rendered the planned A330 variant much more competitive against the Boeing 787 in the battle for the “middle of the market,” according to Airbus. The European airframer has refined the design, which now offers more seats and, consequently, lower seat-mile costs. Airbus has acknowledged that its progress lags two years behind that of Boeing, but officials also point out that current 787 backlog means that airlines ordering today cannot obtain either aircraft before 2010.

Despite the proposed aircraft’s assumed approval under the existing A330 type certificate, Airbus has gone to great pains to emphasize its new features. According to A350 program head Oliver Andries, they include high-speed aerodynamics; flight deck features and flight- and cabin-crew rest locations; fuselage structure and landing gear; engines, nacelles, pylons, and auxiliary power unit (APU); wing, winglets and empennage; wider cabin with new overhead bins; larger cabin-window transparency area and a larger aft galley.

The A350 offers more seats and range, as well as lower costs, fuel burn, and weight, according to chief commercial officer John Leahy. When the company froze the design configuration, it went to its fourth iteration of the A350 in response to analysis of airline requirements.

The new variant sports a slightly wider cabin, with two inches more aisle and centerline headroom and 2.5 inches more window-seat headroom than the 787, claimed Leahy. Airbus now now quotes slightly less generous dimensions for 787 headroom than initial A350 presentations showed six months ago. Window-seat headroom (from floor to passenger service unit) now measures 61.5 inches, compared with 63 inches.

Airbus increased shoulder room in the A350 by re-profiling fuselage frames, while it re-sculpted floor-level sidewalls to improve lateral space. The company has been also using longer sidewall panels that now embrace a third fuselage frame.

Other changes include modified surrounds that expose an 8-percent greater portion of existing windows and projection of “virtual sky-mood lighting” on premium-class ceiling panels. Typically, the A350 will provide 15-percent humidity and a 6,000-foot cabin altitude at typical cruise levels.

Designers have moved the rear pressure bulkhead aft one frame, giving the A350-800 eight more seats than the A330-200. The A350-900, whose bulkhead sits two frames aft, seats an additional 16.

In typical long-range, two-class configuration, the reworked A350-800 cabin provides 26 more seats (258 versus 232) and 600 nm more range than the 787-8, while the A350-900 can either carry 29 more passengers (316 against 287) than the 787-9 or match its range with the same load.

Airbus values the extra A350-800 capacity at $22.5 million a year, arguing that the A350-800 has “the best cost per seat” for hub-to-point travel.

According to Airbus calculations, which assume 4,000-nm range in two-class layout and fuel costs of $1 per gallon, the 787-8 cash operating cost/seat would run 6 percent higher than that of the A350-800. On hub-to-hub sectors, the larger 787-9 would cost 5.2 percent more than the A350-900, claims the company.

The A350-800 offers three-class accommodation for 253 passengers over a range of 8,800 nm, compared with 245 people over a 200-nm-shorter range in earlier iterations. Leahy said the 787-8 has gone from 217 to 223 seats with a range of 8,500 nm. The A350-900 now provides 300 seats (up from 285) over 7,500 nm. At 8,000 nm, the range of the competing 265-seat Boeing 787-9 is now a 100-nm lower than originally projected, according to Airbus figures.

The A350 retains the A330’s Mach 0.82 cruise speed and company officials claim that Mach 0.85 would gain only 15 to 20 minutes on the longest flights. At 540,225 pounds mtow, the A350 will carry a 99,200-pound payload over 6,000 nm or 77,160-pound maximum passenger load over 7,000 nm. Airbus also claims that the A350’s block fuel per seat beats the 787-8’s by 4 percent, and cash cost per seat by eight percent.

Airbus claims a 2-percent advantage in manufacturer’s empty weight for the A350-800 over the Boeing 787-8, or 4 percent for the -900 over the -9. It calculates an operating weight per seat advantage of 1 percent for both A350 models over equivalent 787 designs.

By retaining engine bleed-air (not used on 787s), Airbus says it can use identical turbo-machinery and achieve operational margins similar to those of current engines. Powerplant direct maintenance costs remain the same, as would specific fuel consumption (SFC) for an equivalent power takeoff. Andries said the General Electric GEnx engine would offer 15-percent better SFC than the CF6-80E1. Airbus expects Rolls-Royce to offer the Trent 1000 turbofan.

The program manager suggested airlines can optimize maintenance costs by careful selection of engines and thrust levels. GE offers four GEnx variants, flat-rated at ISA +15 degrees C. With dash numbers identifying power levels, the 75,000-pound-thrust GEnx-75A represents the powerplant with the most “grunt.” The -63A, -68A, and -72A models account for the smaller variants. Operators may choose fixed de-rates of up to 24 percent, or flexible thrust with up to a 40-percent de-rating.

Compared with current aircraft, the A350 will offer 15-percent lower airframe DMC through use of A380 technology, making it “future-proof against obsolescence,” argued Andries. Moves to reduce DMC include a simpler fuel system with fewer parts; extended check intervals and fewer fatigue-related tasks; improved “trouble-shooting”; use of A340-600 engine-air bleed and cabin-loading systems and A380 high-intensity external lighting; more-reliable APU and supplier choice; carbon fiber-reinforced plastics (CFRP) wing structure, aluminium-lithium (Al-Li) alloy materials; simpler air-conditioning, with no pneumatic back-up and trend monitoring on all exchangers; increased intervals between landing-gear/brakes overhauls and lower brake materials costs.

The A350 maintenance manual extends nominal A330 A, C, intermediate, and structural check intervals from 600 flight hours, 18 months, five years, and 10 years, respectively, to 800 hours, 24 months or 10,000 hours, six years, and 12 years. Airbus wants to eventually achieve a more-ambitious 1,000 hours, 30 months or 12,500 hours, seven-year and 14-year intervals.

The manufacturer also claims the A350 will realize greater maintenance cost savings over the Boeing 767-300ER that the 787-8 will offer. Andries cited a Boeing cost-reduction target of 30 percent against the 32 percent Airbus hopes to achieve.

By using 39 percent composites and 21 percent Al-Li, Airbus has reduced traditional aerospace materials content to 40 percent, said Andries. Concern for accidental fuselage damage and wing and empennage fatigue resistance drove the selection. Drawing on experience from the ATR regional turboprop and the A400M military transport, the A350 will incorporate a CFRP wing, which allows Airbus to shave eight tons from A330 weight (before adding heavier engines and pylons). Airbus chose Al-Li skin panels so that operators can use industry-standard procedure for damage assessment and repair.

Over the coming 20 years, Airbus foresees requirements for 3,120 jetliners in the 250/300-seat classes of the A330, A350, and A340-500, according to market forecast and research vice president Laurent Rouaud. Airbus places project breakeven at a loose “400-500” units, said to be “typical for a long-haul program.”