The Airbus Stretch

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ANALYSIS: The incredible evolution of Airbus’s biggest single-aisle

• 15 July, 2019
• SOURCE: Flight International
• BY: Max Kingsley-Jones
• London

The launch by Airbus of its ultimate single-aisle – for the moment, at least – has put Toulouse on the front foot in the battle for the middle of the market. The vibe from the Paris air show was that the A321XLR was a good start – but by no means snuffs out Boeing's ambitions for its own mid-market programme, the New Mid-market Airplane (NMA).

The expected arrival of the 4,700nm (8,700km)-range A320 family variant, due in 2023, will finally give Airbus a single-aisle aircraft that easily has the measure of the aircraft that has been the benchmark in this sector for many years – the Boeing 757-200. It also marks an incredible evolution of an enlarged A320 variant that started life in May 1989 as a "simple stretch" – almost like the fairy tale of the ugly duckling maturing into an elegant swan.

The main changes introduced with the new variant when it was launched were two fuselage plugs – 4.3m (14ft) forward and 2.7m aft – which boosted a typical two-class seating configuration by around 25 passengers, increased weights and double-slotted flaps in place of the A320's single-slotted configuration. The trailing edge was also modified slightly to include a small chord extension in a clean configuration to provide for a slight increase in wing area.

The aircraft was powered by versions of the A320's existing CFM International CFM56 and IAE V2500 engines, namely the -5B and -A5, respectively. They were available at thrust levels up to around 33,000lb (156kN), somewhat higher than offered on the A320.

The A321 was formally launched in November 1989. Appropriately, its first order was placed by the leasing company then run by Steve Udvar-Hazy – ILFC – with a commitment for 16 aircraft. Udvar-Hazy was on hand at Paris last month when his current leasing vehicle, Air Lease, became the first customer to sign for the A321XLR on the opening day of the show.

The A321 launched in baseline -100 form in January 1994 with Lufthansa. This variant weighed in at a maximum take-off weight (MTOW) of 83t and could carry a typical two-class load of 186 passengers over 2,300nm. A higher weight -200 arrived two years later featuring a higher 89t MTOW. The addition in the freight hold of a single additional centre tank (ACT), with a capacity of 2,990 litres (790USgal) in the shape of an LD-6 cargo container, extended the range to 2,700nm.

 

A321LR variant arrived in 2018: 4,000nm, 206 passengers

Airbus

HARMONISATION

Airbus quickly standardised A321 production around the -200 platform, so all aircraft delivered from April 1997 were built to the higher specification. In 2000, deliveries began of a slightly heavier A321-200 with an MTOW of 93.5t. Coupled with extra fuel capacity via two ACTs, the higher weight enabled 3,000nm missions to be flown which in theory provided US transcontinental range to match the capability of its smaller sibling, the A320.

While the A321 had proved popular with customers and provided an Airbus single-aisle with similar capacity to the 757-200, the original platform was never able to match the payload range performance of its rival. The lighter A321 was economically superior when range was not a factor but the 757, with its larger wing, higher weights and more powerful engines, offered impressive single-aisle capability with its range of up to 4,000nm.

Sales of the A321 were sluggish compared with the A320. By the time of the A320neo family launch in 2010, A321ceo orders had steadily risen towards the 900-unit threshold (passing 1,000 orders during 2011). In comparison, A320ceo orders were around 4,500 units.

The launch of the A320neo was a bold decision at the time that not only energised sales of the baseline A320 but has transformed the value proposition of the A321, even though the re-engining exercise added about 1.8t in weight. Finally, Airbus had a product that could hold its head high against the 757 – albeit an aircraft that had been out of production for half a decade by then.

Recalling the decision to launch the re-engined A320 for Flight International’s Airbus at 50 supplement earlier this year, the manufacturer's former engineering boss and chief operating officer Tom Williams said it was not completely straightforward.

"That was a big decision because the fear was that we’d end up destroying the current orderbook, customers would defer and so on. And the A320 was of course the cash cow of the business," he said.

"The other concern was that if we tinker with this product, at what point do we do something that becomes dysfunctional?"

The original motivation behind the re-engining was concern about the threat from Bombardier and its CSeries (ironically a programme now run by Airbus as the A220).

"We launched the A320neo with the express purpose of killing the CSeries," he says.

"Our internal modelling of an all-new aeroplane [design] showed it was only going to bring another 3% of performance improvement over the [re-engined] A320neo's 15%. It was an argument that said the all-new single-aisle really needs to wait until the next step of engine technology, like contra-rotating open rotors, and that's not going to come until the latter part of the next decade, so we should get on and do this re-engining."

In the run-up to the introduction of the re-engined family, Airbus developed a winglet modification for both current and Neo versions dubbed the "sharklet", which delivers a performance improvement of up to 3%.

The baseline A321neo utilised the existing weight options offered on its predecessor, and the variant followed the A320neo in the development plan (although at one stage the A321neo was slated to trail the A319neo in the timetable). The re-engined A321 is offered with the CFM Leap-1A33 rated at 32,900lb thrust and the Pratt & Whitney PW1133G providing 32,700lb thrust (both at "Airbus equivalent thrust" ratings).

The re-engined stretch proved so popular that by the time of its first flight in February 2016 its orderbook (1,114 aircraft) had already exceeded sales of the 757. Meanwhile, the A321ceo had enjoyed a sales surge, with orders having more than doubled from 2010 to 1,642 aircraft.

Fairly early in the A321neo’s development, Airbus identified a way to increase the cabin’s certificated maximum capacity through a redesign of the door layout and changes in the cabin arrangement (including a recessed galley). Dubbed Airbus Cabin Flex (ACF), the changes effectively "stretch" the A321 by boosting maximum seating by 24 seats to 244 passengers.

The ACF configuration was introduced into the production flow in 2018 but early A321neos were built with the original door arrangement and some customers are still opting for that version to retain compatibility with existing fleets.

The ACF configuration is the cornerstone of an extended-range A321neo variant launched in 2015 and branded as the A321LR. Officially, there is no A321LR-designated variant in the A321neo product line-up. It is in fact a variation of the new A321-200NX build-standard, based on the ACF platform.

Boeing 757-200 has long led the sector

Max Kingsley-Jones/FlightGlobal

ENHANCEMENTS

This variant was introduced with the new build standard in 2018, incorporating structural changes allowing up to a 4t MTOW increase to 97t. The -200NX can be equipped with up to three ACTs (one forward and up to two aft) to create an ultimate capability of flying a 4,000nm mission with 206 passengers in two classes. The LR's ACTs are slightly larger than the previous version, each with a capacity of 3,120 litres providing about 250nm more range.

With the introduction of the LR (incorporating three ACTs), Airbus finally had an A321 capable of challenging the 757, while at the same time achieving a 25% lower cost per seat. But customers still had an appetite for more performance. Airbus saw an opportunity to refine the A321neo further to meet these needs and at the same time create a disruptive force in the sector targeted by Boeing with its NMA.

After much speculation, Airbus formally unveiled the A321XLR on the opening day of the Paris air show, with deliveries due to begin in early 2023. Derived from the LR (or -200NX) the XLR (designated A321-200NY) has structural reinforcements to allow the MTOW to increase by up to 4t to 101t. Powered by the LR's current CFM International Leap-1A and PW1100G engines, the XLR features a 12,900 litre permanent rear centre fuel tank (RCT) which holds the equivalent of four ACTs.

Another key change is a redesign of the inboard double-slotted flaps into a single-slotted design. This saves weight and reduces drag while maintaining take-off and landing V-speeds equivalent to the A320ceo, says Airbus.

But significantly, no decision has been made yet over whether this major piece of engineering will be introduced as a block change, thereby simplifying the number of build-standards offered on the A321. Complexity of specification options on the current A321 is an issue that has been hampering Airbus production for some time already, leading to lengthy delivery delays.

The design changes will allow the XLR to operate a 4,700nm mission with an optional ACT installed in the forward hold. Airbus chief commercial officer Christian Scherer says this typical long-range mission would probably involve a two- or three-class layout and seating for "around 200" passengers. He adds that the RCT fuel tank has a weight "equivalent" of a single ACT and the volume of four ACTs, but only occupies the space in the cargo hold of two.

Air Lease was the first to sign up for the XLR, placing 27 firm orders, and the lessor's chief executive, John Plueger, is confident that the new model will be very popular.

"I think you're going to see this aircraft become highly used transatlantic and between north America and south America. Already we have huge expressions of interest from many of our current A320neo and A321neo customers – we see huge demand," he says.

"This airplane is hugely efficient compared to widebody aircraft that it might replace in some of these [middle to long-range] market places."

A321-100 trailing-edge

Max-Kingsley-Jones/FlightGlobal

In total, Airbus secured strong backing for the XLR's launch with orders and commitments from 12 customers for 249 A321XLRs, including a mix of new orders and conversions from other A320-family orders.

Airbus has not disclosed the catalogue price for the new variant, but it is understood to be priced at a small premium over the LR versions. However, sources indicate that the airframer was offering some sporty "one night only" deals to encourage existing A320neo customers to switch over to the XLR and be part of the launch party.

Over the three decades since the A321 was originally launched, Airbus has more than doubled the aircraft's range, raised the MTOW by over 20% and delivered a 10% increase in maximum seating without extending the fuselage. Cirium's Fleets Analyzer shows that total orders for the A321neo variants are just shy of 2,400 aircraft, while the entire A321 orderbook is approaching 4,200 aircraft.

Altogether, the A321 accounts for just over one-quarter of all Airbus single-aisle sales, while the re-engined version makes up over one-third of all A320neo orders. But given the current sales momentum and the energising of its capabilities with the LR and XLR variants, just how successful can the A321neo family be?

"Airbus themselves predicted historically that the A321 would account for up to 50% of A320-family deliveries in the future," says Rob Morris, global head of consultancy at Ascend by Cirium. "Whilst there are clearly constraints that have prevented this in the past, the advent of the XLR can only help towards this 'goal', since it further enhances the already strong proposition offered to the market by the A321neo."

Morris says that the significant performance enhancements offered by the XLR equate to enhanced network flexibility, so the variant can be expected to be "a reasonably good seller".

But he wonders how well sales will compare to the baseline A321neo ACF variants (i.e. the 200NX): "I think it depends upon the structural weight delta between the XLR and the ACF (when enabled for three ACTs but not necessarily installed). Does the XLR's permanent tank cost airlines much in weight – and thus unit cost terms – and is the loss of the hold capacity (for the fixed tank) material to revenue?"

Morris says that if the answer to either or both is marginal, it is difficult to see why customers would not want the flexibility the XLR offers. If the impact of either is material, then the XLR market will be more niche.

"I think the initial sales indications, with a number of customers trading orders up to the XLR, is already telling us that airlines are going to like the product. But in overall terms I think it is too early to tell exactly how much they like it and thus what portion of A321neo sales in the long term will be XLR," adds Morris.

Scherer predicts "hundreds" of A321XLR orders and the manufacturer is understood to have conservatively estimated demand for at least 1,500 XLRs. This may well be a mix of orders that would have already gone the A321LR's way as well as incremental business, but the XLR's arrival effectively lets Toulouse "park the (Air) bus" in front of the goal Boeing is aiming at with the NMA.

Qantas joined the XLR's Paris launch party with 36 orders

Airbus

Airbus Cabin Flex door arrangement changes

 

[AAS]

I wonder if it will have 

SDDCDM

(Système d'augmentation des caractéristiques de manœuvre)