The A320 family production schedule shows that the airframer plans to offer the the twinjet for at least another 10 years

Air France took the unprecedented step in May of placing orders to replace an ageing fleet with effectively an identical model, the Airbus A320. This illustrates the stagnation of the single-aisle market, a blight that has never afflicted the widebody sector.

Air France was a pioneer of the A320 - it was launch customer, introducing its first "electric jets" in 1988 - and the fact that after a relatively minor upgrade the twinjet is still competitive today arguably shows how advanced it was when it entered service. But it also highlights that little technical progress has been made by this sector over 20 years. Traditionally, after what is effectively a lifetime in aircraft terms, Air France could have expected its replacement machines to have demonstrated a double-digit operating cost advantage over their predecessors. Despite a series of product improvements in recent years - with more in the pipeline - the reality is that a 2009-10 A320 is unlikely to get close to an improvement of 10%-plus over a similar aircraft delivered 20 years ago.

GoAir.In A320 
 © Airbus

Air France's senior vice-president for new aircraft and corporate planning Pier Vellay says that while products in the long-haul sector have enabled the carrier to cut operating costs by an average of 1% annually, this has not been the case for the medium-haul sector.

Spiralling Fuel Costs

"Our goal is to make up for lost time," says Vellay. "We have to convince the manufacturers to decide on an aircraft or sub-family." He hopes to get a timescale for such a development from the airframe and engine manufacturers by the end of the year.

Air France's desire - typical of many airlines that are feeling the pressure of increasing fuel costs - is to see something ready by, or shortly after, the middle of the next decade. But the noises coming from the airframers indicate that this is optimistic.

A production forecast for the A320 recently revealed by Airbus predicts the twinjet will remain current for at least another decade. The airframer has a string of minor updates in the pipeline to boost the twinjet's performance, and while it admits it is evaluating a potential major upgrade in the form of a Pratt & Whitney GTF geared turbofan version, it plays down the likelihood of such a development.

Airbus has delivered over 3,500 A320 family aircraft since 1988, and has 2,600 orders on firm backlog. It sold 914 aircraft last year and production is sold out through 2011-12, with output set to rise to 40 a month from 2010. By then, monthly output of A320s at the new production line in China will be heading towards four (see box).

Product Mid-Life

"Potentially 8,000 aircraft could come out of this family over the next eight- to 10-year period," says Airbus vice-president marketing Colin Stuart. "That suggests that we're only at the mid-life of the product."

Simple arithmetic indicates that Airbus expects to sell at least 2,000 more A320 family aircraft before any new-generation single-aisle Airbus becomes available. It remains to be seen whether the last of those 8,000 A320s will be powered by the same basic engines the twinjet had when it entered service.

While CFM International and International Aero Engines have continually developed their powerplants to boost efficiency and reduce maintenance costs - the latest upgrades being dubbed the Tech Insertion and Select One respectively - a switch to the GTF could enable the A320's efficiency to take the sort of step Air France wants before any all-new airliner emerges from Toulouse or Seattle.

Airbus will evaluate the GTF on its A340-600 flying testbed this year. While the engine promises major fuel burn savings, A320 programme executive vice-president Alain Flourens says the studies of a potential mid-life update with the engine for the A320 "won't be limited to just the specific fuel consumption, we'll look at all the ramifications for the aircraft". Flourens says "the issue is to see what real improvement the engine could offer, when it would be available and how long the life of the family would be when the engine is introduced".

Timing is critical. "We don't want to introduce a new engine for just a few years," Flourens says. He adds that Airbus also has to establish what a move to a new engine would mean to customers "as it could result in a sub-fleet for operators".

The more immediate priorities for Flourens are some short-term initiatives to keep the A320 family's competitiveness sharp in the face of new regulatory requirements while also examining new ways to improve the functionality and performance of the aircraft (see graphic). And with no radical replacement on the horizon, Airbus has undertaken a major programme to extend the life of the twinjet, which is planned to ultimately result in the flight-hour limit being tripled to 180,000h. Dubbed "extended service goal", the programme should ensure that the fleet can remain operational well into the second half of the century.

Airbus spends c100 million ($156 million) every year for the development of the current single-aisle family, and modifications are required to comply with new cabin flammability, 16g head-impact seating and fuel tank inerting regulations. "All of these will add weight," says Flourens. He points out that the ongoing effort to reduce drag, weight and fuel consumption will help offset the modifications required for the new legislation.

The changes to meet the new regulations are needed soon. Updated burnthrough requirements will require new cabin insulation to be introduced on new-build aircraft from September next year, which will add around 40kg (88lb) for the A320, says Flourens.

While there is no firm timing for the enforcement of the fuel tank inerting requirements, Flourens says Airbus is working towards a date of May 2010. "This is a 'forward fit' [on new-build aircraft] adding 50kg [110lb]," he says.

Although the 16g passenger/cabin attendant seat requirement is enforced only by the US Federal Aviation Administration, Flourens expects the ruling to be extended worldwide during 2009. "We've not estimated what the weight penalty for this will be," he says.

To counter this growth, Airbus aims to shave off 250kg for A320s delivered from 2010 with a three-pronged weight-reduction effort addressing the cabin, the structure and materials, and systems. "Roughly one-third will come from each area," says Flourens.

For example, redesigned cabin floor panels made of a new material will save 30kg and will be introduced as soon as they are available. A redesigned, lighter cabin offering a saving of up to 80kg was introduced last year.

An example of a structural weight-saving planned is a production change to the shape and the "pocketing" of the wing stringers, while "changes to the rods in the cabin insulation" will reduce weight in the cabin air conditioning system, says Flourens.

Airbus is midway through the introduction of a drag reduction programme with aerodynamic upgrades encompassing a new engine pylon, surge tank vent and reprofiled belly fairing. Deliveries of the first two items have begun and the latter is due to be introduced by the end of this year, with the combined package providing "well over a 1%" reduction in drag.

While "other ideas" are being examined for further airframe reduction, Airbus is hoping its revival of studies into a blended winglet for the A320 in conjunction with Aviation Partners - the US company teamed with Boeing for the US airframer's winglet programmes - will deliver a significant efficiency improvement.

Airbus made two evaluations of winglets for the A320 in 2006 - one designed in-house and one by US company Winglet Technology - with the target of achieving "a couple of per cent" reduction in fuel burn.

At the time, the performance improvement did not offset the weight increase caused by the strengthening required. Flourens says Airbus "will carry out a short flight-test programme of the API winglets" on the company's A320 development aircraft during July. A decision on whether to proceed is planned by year-end.

The wingtips will be strengthened for the test with doublers and the trade-off of the weight increase against fuel burn benefits measured. The weight-reduction programme would help counter the strengthening, says Flourens.

Environmental Improvements

As part of studies into longer-term efficiency and environmental improvements, Airbus may undertake a demonstration of an electric taxi system on an A320 this year. The airframer is in discussion with potential partners. The test would involve the electric motors, rather than the engines, being used to propel the aircraft. "We will examine the power needed to shift from the standstill position, and we'll look at the trade-off between the additional weight and the benefit in terms of fuel consumption," says Flourens.

For the trial, electrical power will be provided by the auxiliary power unit, but Flourens says that alternative sources are being examined for the longer term, such as fuel cells.

Flightdeck improvements are in store. A class 2 electronic flight bag and airport navigation display are being evaluated, while the business case to offer the "brake to vacate" function developed for the A380 is being considered. The latter device enables pilots to designate the target exit point on a runway before touchdown and the autobrake modulates the retardation to achieve this. Flourens says Airbus is looking at various ways it could incorporate it into the A320 flightdeck, such as on the proposed EFB or the existing navigation display.

GPS and microwave landing system capability was introduced last year, and Airbus has launched a programme to offer an FMS landing system on the twinjet. An upgrade to enable A320s to achieve FANS B+ capability is also being developed, and Airbus has begun a feasibility study into introducing ACARS over GSM/IP pilot/controller communication functionality into the A320 flightdeck. Airbus says that the first laboratory tests are expected this year and "if the conclusions are positive, then service entry is likely by early 2011".

Airbus is clearly leaving no stone unturned as it drives A320 product development and sets its sights on ultimately matching the 737 trilogy's current orderbook of 8,000 aircraft.

Gearing Up For A320 Production In China

Airbus is about to follow in the footsteps of McDonnell Douglas with assembly of the first A320 in China set to begin in August.

Its US rival set up an assembly line in the country during the 1980s in conjunction with Shanghai Aviation Industrial Corporation (SAIC). But with the venture having produced just 35 MD-80s and two MD-90s over a 15-year period, few would disagree that the MDC/SAIC programme failed to realise its potential.

Airbus is confident it will make a better go of it in China than its predecessor. The airframer has more than 400 single-aisle aircraft on order from Chinese airlines and it aims to quickly ramp up output.

The plant, in Tianjin on China's north-eastern coast, comprises an all-new joint-venture assembly facility and Airbus-owned delivery centre. Airbus is the majority shareholder in the FAL with a 51% share, and a consortium of Chinese industry owns the remainder. The Chinese partners comprise the Tianjin Free Trade Zone (60%), China Aviation Industry Corporation I (20%) and China Aviation Industry Corporation II (20%). The first delivery - an A320 for Sichuan Airlines - is scheduled to take place in June next year.

Output is set to reach four aircraft a month by 2011, but this will not be sufficient to meet the current level of demand from Chinese airlines, so the balance will be provided by the Toulouse and Hamburg lines, says A320 programme executive vice-president Alain Flourens. Tianjin could produce up to seven aircraft a month with minor adaptations, "but today it is not planned to go above four", he adds.

All the major components for the Chinese line travel by container ship via the existing final assembly line in Finkenwerder, Hamburg, which is the "virtual first assembly station" for Tianjin, says Airbus A320 family programme chief Alain Flourens.

The first components - fuselage, wing and empennage - began their journey to China from Hamburg on 24 June and "assembly will begin on 18 August", Flourens says.

The aircraft sections, on transport jigs, are barged to Hamburg's container port for their voyage by container ship to China. After arrival at the port of Tianjin, the sections then travel 20km (12 miles) by road to the Tianjin Airbus facility.

Florens says that the Chinese final assembly line building , which is already completed, is a "copy and paste of the Hamburg one in order to have the same processes, documentation and so on", and will be able to produce both the A319 and A320.

The Chinese FAL will also be responsible for cabin furnishing and first flight - although the latter will be performed by Airbus pilots and flight engineers at the delivery centre.

"Once the aircraft is ready for delivery it will be handed over to the delivery centre, which will handle all the relationships with the customer," says Flourens.

Training of 200 Chinese staff has been taking place in Hamburg in preparation for the launch of assembly and, through to the end of 2008, around 100 expatriate workers from France and Hamburg will work at the Tianjin final assembly line and delivery centre. The number of expats will begin to decrease significantly once full output is achieved from 2010, says Airbus, eventually falling to around 20.

By the end of this year, around 300 Chinese and European staff will be employed at the Chinese final assembly line, with this number rising to around 500 when output reaches four a month in 2011. The delivery centre will employ 70-80 people, including functions other than delivery such as IT and engineering support. Of these, around 40-50 will be expatriates.

Boeing Cautious On Next Generation of 737

The Boeing 737 in its various guises has been the backbone of the short-haul sector for 40 years. Overall production has exceeded 5,750 units and the backlog for the current model is more than 2,200, putting total sales at almost 8,000 - an achievement comparable with that of the Douglas DC-3.

Around 2,600 examples of the current Next Generation family have been delivered, and output is averaging around 30 a month. On that basis Boeing has almost six years of production on backlog, so it is no surprise that the airframer is in no hurry to develop a game-changing successor.

Unlike Airbus, Boeing is unwilling to put a number on the ultimate number of aircraft it expects to produce. Nor will it say how long production of 737NGs could run. The US airframer has been engaged in 737 replacement studies for years and until recently, the indications had been that such an aircraft would emerge by the middle of the next decade.

Futura 737
 © Boeing

Anita Polt, regional director in Boeing Commercial Airplanes' product marketing department, says the airframer decided recently "that we need more time to study the emerging technology to come up with an airplane that is compelling enough to replace today's single-aisle aircraft", and that it will not come to market until at least "the latter part of the next decade".

Polt says that the efficiency of today's single-aisles has "set the bar high" and it will be a major challenge to achieve the performance targets set for the replacement aircraft of 15% lower fuel burn and 25% better maintenance costs. "These are big targets and you can't get there by just changing materials. We've got to have breakthroughs in propulsion technology, aerodynamics, systems and materials."

Although its origins extend to the 737-100 of 1967, the 737NG is the third iteration of the twinjet and entered service almost a decade after the A320 following a "top-to-bottom" redesign. Boeing views it as effectively an all-new aircraft. Its in-service enhancement programme has been so prolific that many items that Airbus has just introduced or is planning for the A320 are already offered on its rival. These include winglets (introduced in 2001) and cockpit upgrades - head-up display (2001), vertical situation display (2003), GPS landing system (2005) and Class 3 electronic flight bag (2006).

Unlike the A320, the 737NG already complies with the 16g head-impact seat requirement, as it was a US Federal Aviation Administration certification requirement. Boeing phased in fuel inerting (a nitrogen generating system for the centre tank) this year on new-build 737s, which adds less than 23kg (50lb). The inerting system is being retrofitted to the in-service fleet as well.

Around 90% of 737s being delivered now have winglets developed by Aviation Partners Boeing. These provide fuel burn savings of "up to 4% depending on the route", says Polt.

One area where the 737 is playing catch-up is carbon brakes. These have been available on the A320 since day one, but Boeing has only just begun offering them as an option on the 737 "as maintenance costs have now reduced to the same level as steel brakes", it says.

Boeing is reluctant to disclose development plans for the 737. This may partly be because it believes the 737 is already "a lighter, more aerodynamically efficient aircraft that burns less fuel" than its rival.

Polt says: "We've got a number of studies ongoing for features that would enhance the 737NG's passenger comfort or efficiency by reducing weight or fuel burn. In terms of product development or replacing the single-aisles, we've got a big suite of things we're looking at, but we're not planning on putting a GTF or anything like that on the 737NG in the next couple of years."

Source: Flight International