Despite the fact that final assembly of the 4,000th example is now under way, the A320 single-aisle twinjet may be only at the midpoint of its production life, according to Airbus. Marketing vice president Colin Stuart has suggested that a 5,000th A320 could enter service in 2011. That would be no more than 30 months after MSN4000, an International Aero Engines V2500-powered A319, is delivered to Brazilian operator TAM as scheduled for this July. Stuart even sees the potential for an 8,000th aircraft within 10 years.

Against an initial anticipated market for about 750 aircraft, Airbus had taken orders for more than 6,320 by last month and delivered over 3,850 to 220-plus customers. Last year, the manufacturer took orders for 472 A320-family variants and delivered some 386 examples. In February, it delivered the 500th A321, the largest variant, from more than 750 on order.

Airbus has raised the prospect of another 10 years’ production as the first Chinese-assembled A320 is being prepared for delivery to Dragon Aviation Leasing this month for operations by local carrier Sichuan Airlines. It is to be followed by more A319s or A320s from the company’s final assembly line in China (FALC) at Tianjin, where production is planned to reach four aircraft a month by the end of 2011.

In addition to final assembly, Airbus and Xian Aircraft Industry Co. (XAC) have agreed that XAC should take over from Airbus UK completion and testing of A320 wings, which will be performed in a new facility at Tianjin. The operation should start at the end of this year, with the first fully equipped wing set being delivered within three months and subsequent turnover being accelerated to match A320 completion rates by the end of 2011.

Overall, A320 production is understood to be sold out beyond 2011, by which time manufacturing flows might exceed the current 36 units per month, a rate that Airbus already has warned will be cut to 34 beginning in October. Requests from airlines to defer delivery of aircraft are understood to have accounted for some production slots that otherwise have been sacrificed to permit the rate change. In suggesting that as many as 40 a month might be assembled by 2011, Airbus executives appear confident that the planned reduction in three months is a one-off adjustment.

After more than 20 years of development, Airbus is spending about $135 million a year to enhance the A320, according to product marketing director Stuart Mann. More than 650 have been delivered since a new cabin interior (available as a weight-reducing retrofit for earlier aircraft) was introduced two years ago, and the manufacturer has recently reduced drag and improved maintenance schedules. Now, Airbus is offering an optional increase in takeoff weight and the prospect of further savings through enhanced aerodynamics. It also is planning to extend airframe service life.

Late last month, Airbus was awaiting imminent formal European airworthiness approval to raise the maximum takeoff weight by about 2,205 pounds to 172,000 pounds, initially for IAE V2500-engined models and subsequently for those with CFM International CFM56 powerplants. That is about six months later than the manufacturer predicted last November.

The increase, which does not affect operating empty weight or require structural changes, arises from introduction of new software that allows operators to benefit from the wing’s load-alleviation function. It will apply to A320s from MSN1903–a 2002 model that was the first with a reinforced tailplane (or horizontal stabilizer).

The new flight-control software operates ailerons and outer spoilers to reduce wing bending moments and redistribute aerodynamic loads during maneuvering and gust turbulence. It also provides a modest increase of 150 nm (or 10 passengers) in payload-range performance, and is seen as being especially attractive for North American transcontinental and longer European charter routes.

Aerodynamic changes introduced earlier this year have provided a 1-percent reduction in cruise drag, according to Mann. Improvements include a redesigned inlet to the surge tank, changes to the upper belly fairing and reworked engine pylons. Following tests conducted in 2006 and at the end of last year, Airbus is considering possible use of winglets, a move that could be confirmed here at Le Bourget this week and which would represent an advance on the wingtip fences that have graced A320s from the beginning.

“Analysis of results is under way, but winglets are something we are looking at to ensure the A320 family remains competitive,” said Mann. After trials with different winglets designed in-house, the manufacturer has also evaluated “blended winglet” devices provided by Aviation Partners, which joined with Boeing to develop winglets for the Boeing 737NG. Airbus wants to identify performance and economic benefits of these devices before deciding whether the technology could be formally integrated into an Airbus program.

Lower maintenance costs should accrue for A320 operators following the manufacturer’s adoption of increased intervals between scheduled inspections. Intervals for principal checks have been extended by 20 percent, said Mann. “Most of the tasks previously carried out every 15 months may now take place every 20 months or 6,000 flight hours,” he explained. “The five-year ‘heavy’ check can be extended to six years, and the 10-year checks prolonged by two years.” Airbus plans additional changes to extend intervals further, with new packages likely to be introduced at the end of this year and 12 months later.

The manufacturer also is working on an airframe life-extension program. The current design service goals of 48,000 flight cycles and 60,000 flight hours may be increased to extended service goals (ESGs) of as much as 90,000 cycles and 180,000 hours, respectively. The change would be made in two steps: an initial ESG-1 increase would take design goals to 60,000 cycles and 120,000 hours next year “with tests continuing as long as is economically viable” up to the higher values, concluded Mann.