The A321XLR ‘Game-Changer’

There has been a lot of media interest in the introduction of the A321XLR into Iberia airline operation, with the term ‘game-changer’ often applied to it.

Just how is the A321 XLR a game changer and how does it achieve it?

Image: Airbus Media Page

Primarily, it offers medium-range, narrowbody capability at fuel efficiencies similar to modern long-range widebody aircraft. This performance makes it an ideal aircraft for direct flights that include at least one secondary airport or to open up new routes.

However, it’s unlikely the A321XLR will directly replace many established widebody hub-to-hub operations for various reasons discussed later.

Image: Airbus Media Page

‘Hub to secondary airport’ is generally a more appropriate characterisation of A321XLR usage than a ‘point to point’ flight between two secondary airports. The ‘hub’ provides the necessary traffic volume, while a direct flight to a secondary airport offers convenience and faster total travel times for the customers. Note: even the A321XLR requires city pairs with about 150-180 customers regularly wishing to fly on each pair of return flights.

In many cases, the direct flight also significantly reduces the total fuel burn per passenger compared to a 2-leg trip, combining a widebody ‘hub to hub’ flight with a shorter regional flight. The direct flight’s fuel saving comes from the shorter total flight distance and the elimination of the fuel penalties related to the descent-landing-taxi-take-off-climb cycle between the two flights.

757 Replacement 

The A321XLR payload/range capability is not new.

The Boeing 757-200 has successfully provided this capability for almost 45 years, and still does, although it no longer delivers the fuel savings relative to modern widebodies.

However, the A321XLR’s ~25-30% improved fuel efficiency compared to a winglet-equipped 757 reestablishes the approximate parity with modern bodies for these ‘hub to point’ flights.

How does the A321XLR Achieve this Improvement?

The fuel burn improvements are primarily related to the A321XLR’s 30% smaller wing relative to the 757-200, which decreases the aircraft weight and drag, and newer more efficient engines, which are 10-15% more efficient.

These changes reduce the A321XLR’ MTOW by about 10% relative to the 757-200. High-speed aerodynamic technology’s contribution is small (assuming the 757 is winglet-equipped), and mostly due to A320 drag clean-up programmes.

The two aircraft achieve similar approach speeds despite the A321-XLR’s much smaller wing due to the A321XLR’s considerably, i.e. 20%, lower Maximum Landing Weight (primarily due to the lower Operator Empty Weight, OEW), and its 15-20% higher maximum usable approach lift coefficient (a smaller wing providing more lift at a constant speed).

The A321’s superior low-speed aerodynamic performance also benefits its take-off performance, requiring a lower thrust/weight ratio (lower thrust engines per tonne of Maximum Take-Off Weight (MTOW).

However, the A321XLR’s smaller wing offers considerably less internal volume for integral fuel tanks, a feature that has constrained the basic A321’s range capability since it launched in the 1990s.

Additional range A321 operations historically always required auxiliary fuel tanks, which are removable units installed inside the forward and aft baggage holds. The previous A321LRs (note: no ‘X’) required up to 4 auxiliary tanks fitted in the freight hold to carry enough fuel for ~4,000nm missions.

However, auxiliary tanks are heavy (for the fuel volume provided), which degrade the aircraft’s fuel efficiency and reduce its maximum payload capability.

The A321XLR achieves about 700nm more range than the LR variant through a 4-tonne rise in its MTOW and a lower OEW (>1 tonne). Both changes increase the available fuel mass and hence range.

The lower OEW mainly involves replacing the 4 auxiliary tanks with a single integral fuel tank in the lower fuselage, just aft of the wing box. Its weight is equivalent to just one of the auxiliary tanks (reducing the OEW by 1 tonne or about 2%). The XLR retains the option of auxiliary tank installations for even more range.

This A321XLR’s integral fuel tank in the lower fuselage is unique among modern commercial transport aircraft, requiring considerable effort to reach certification.

Hub-to Hub Limitations

As noted earlier, the A321XLR is probably not a ‘game-changer on hub-to-hub routes.

The main reasons are they often do NOT offer fuel efficiency advantages over modern widebody aircraft on many routes when considered on identical routes. The widebodies have higher aerodynamic and propulsion efficiencies.

Weight Efficiency

The relative difference in weight efficiencies between the A321XLR and widebodies is less clear and dependent on proprietary details, design decisions and freight traffic levels on a specific route.

Generally, narrowbody airframe structures typically operate at lower working stresses, requiring heavier structures for constant design loads. It is because of their design for a high-cycle/low flight hour operation compared to the low-cycle/high flight hours requirement for widebodies. Note: ‘low’ and ‘high’ are relative.

However, the A321XLR structural design likely trades higher working stresses for a shorter service life, i.e. fewer lifetime flights, due to its expected operation on fewer but longer flights.

Modern widebody aircraft include a significantly higher proportion of lower-weight composite and titanium structures on components using aluminium and titanium, respectively, on the A321XLR.

However, widebody aircraft typically include a few percent fuel efficiency penalty for their 7,000-8,000nm range capability relative to a corresponding widebody aircraft designed for the A321XLR design range.

Cabin equipment further blurs the issue. Consider a widebody type with a cabin designed for 5,000-8,000nm operations operating on potential A321XLR routes. If the A321XLR has a high-density cabin, it should gain a fuel efficiency benefit. The balance moves back towards the widebody aircraft if the A321XLR cabin also contains a relatively large proportion of lie-flat premium seats as the passenger count reduces and the cabin weight increases.

Similarly, the widebody position improves with a high-density cabin configuration, although the resulting high seat count is probably difficult to fill on a route suitable for an A321XLR.

Aircraft Design Choices

Widebody aircraft wing and engine sizing, i.e. weight, also assumes a considerable freight payload in addition to the standard passenger payload. The A321XLR, like all narrowbodies, does not, which should result in weight advantages, but only on routes without freight traffic.

However, many hub-to-hub routes include considerable freight payloads which the A321XLR cannot carry.

The A321XLR’s 0.78 cruise speeds are 5-10% slower than modern widebody aircraft, increasing flight times by up to 1 hour on the A321XLR‘s longest routes. These penalise the A321XLR’s time-based operating costs, might reduce revenue earning potential (network-dependent), and the slower A321XLRs can obstruct faster widebodies in congested airspace.

Finally, any slot-constrained hub airports will likely penalise the smaller capacity A321XLR operations over larger capacity aircraft to maximise their revenue and profits. Smaller aircraft command lower landing and handling fees. Fewer passengers also reduce the revenue for the terminal shops (part of which flows to the airport operators) – more shop sales = higher shop rental fees.

‘Game-Changer’ or Not

The additional ~700nm range capability offered by the A321XLR relative to the slightly earlier A321LR makes the aircraft a true replacement for 757-200 in payload/range terms.

However, the game-changing element is the 757-200 payload/range capability combined with a fuel efficiency that is close to modern widebody values.

The aircraft has no other narrowbody competitor in production or even in development, giving the A321XLR an uncontested market for at least the next 5-10 years.

If this market sector develops significantly, Airbus are well-placed to profit considerably from it.

The evidence thus far is that there is a significant market - Reuters reported over 500 A321XLR sales at the end of October 2024 as the 1st A321XLR entered service. It also has a considerable head start over any likely competitor.

Boeing Potential Responses

Boeing’s current focus is the certification of the 777-9 and the remaining 737 Max variants (7, 9 and 10).

The 737 Max 10 will not compete with the A321XLR’s range capability. Its cabin floor area is similar to the A321’s, allowing it to compete at shorter flight distances with shorter-range A321neo variants.

To match the A321XLR’s range capability requires a fundamental redesign of the 737 Max 10 involving a considerably higher MTOW and engine take-off thrust (at least 10-15% for both). These changes require a new wing design and a redesigned central fuselage section.

It is essentially a new aircraft and probably beyond the ‘Grandfather’ certification basis used by the Max aircraft.

Reengining Boeing 757s is not going to happen!

Retrofitting new engines could theoretically recover 15-20% of the fuel burn deficit, but even the youngest airframes are now over 20 years old and likely have little remaining fatigue life.

The 757 production line no longer exists, so new-build airframes would offer little advantage over a new aircraft.

A re-engined 767-200 is a theoretical possibility, but unlikely! The 767 production continues to produce KC-46 tanker aircraft. However, it would need to integrate a new engine design to be competitive (expensive). It would likely struggle to match the A321XLR’s economics.

For the last decade, a potential Boeing New Midrange Aircraft (NMA) targeting the A321XLR payload/range occasionally appears in the trade press. However, it’s unlikely to progress beyond conceptual and preliminary design until the certification of the other types frees up the cash needed for its development.  

The NMA’s main challenge is the A321’s production costs due to its assembly as part of the extremely high-volume A320 production system, which currently pumps out almost 600 aircraft (of all variants) every year. This production system has already produced over 11,000 airframes, so only incremental capacity requiring larger facilities incurs further investment.

A full new NMA assembly line producing 100-200 examples per year simply cannot compete on cost unless there is a fundamental step-change in the production process.

No other airframe companies are considering this market sector.

Image: Airbus Media Page

Summary

In terms of Game Changer, the A321XLR offers performance that has no obvious and direct competitor in the next decade and has already racked up considerable sales.

The Game-Changing could extend well beyond the A321XLR to the broader Airbus competitive position.

Having the only practical product in any significantly sized market sector clearly skews the broader overall market share towards whoever provides that product.

It also provides indirect leverage for other related products (crew and maintenance commonality with other types) and/or offers financial headroom in support of broader multi-type sales campaigns.

The A321XLR looks like an awesome move by Airbus.