As befits the Paris air show, Airbus’s head of future programmes likens the technology selection strategy for a next-generation single-aisle aircraft to the cultivation of grapes for fine wine.

“In the early phase of the year, you let the wine stock grow different branches,” said Bruno Fichefeux, speaking to FlightGlobal at Le Bourget.

“The [viticulturist] comes and look at the different branches that grew and picks the strongest one, the one that has more fluid and more strength to bear fruit. And then comes a time of trimming and guiding this single branch that will carry the whole weight of the fruits.

“That’s exactly where we are today. We have different branches going in different direction. We need to look at which one will be the strongest.”

Airbus still has branches to trim in the next-generation single-aisle development – a critically-important process, because the aircraft will succeed the bestselling A320neo.

Fichefeux says the open-rotor engine is the primary driver: the airframer is working on a “very thorough plan” to mature the CFM RISE powerplant, with a tight end-decade constraint, putting the proposed powerplant “under a timeline tension”.

“Otherwise, you could continue to explore and investigate forever – that’s what every engineer likes to do,” he states. “So we are putting that now in a convergence tunnel.”

The engine is one of several technological options under exploration, but Fichefeux is confident that the timelines of other innovations are manageable.

“We don’t see any major technological disruption that would justify us to wait longer,” he says. “Because the other disruption that we bring in the aircraft will be able to come to maturity faster than the engine.”

Fichefeux says the airframer is between the initial exploration phase and the emergence of a potential concept aircraft, which could then be refined through discussions with potential airline customers.

“By the end of this decade, we want to be launch-ready,” he says. “We need to go from technology exploration, to fine-tuning a concept, to prepare the launch and push the button.”

But the aircraft design process, he adds, must run parallel to considerations over the digital infrastructure, industrialisation set-up, and supply-chain readiness, in order to meet ambitions for service entry in the second half of the 2030s.

“Ideally, the earlier, the better,” says Fichefeux. “We are betting on a very disruptive design, and this needs to come to maturity so that we are at the level of confidence to say ‘that’s a concept we bet on – it’s proven, it’s demonstrated, and that’s the design we’re going to pursue down the road.

“We are not yet at that phase because we need to test further.”

The open-rotor engine is gradually advancing – Fichefeux puts it at technology readiness level 3, the stage of experimental proof-of-concept – but he says Airbus needs to “hedge our bets” with other engine options.

While supply-chain choices have yet to be made, Fichefeux says: “On the technologies, there are some decisions that we’ve taken internally and then there are some very big trade decisions which are still open.”

These open decisions include the level of hybridisation – the use of batteries, and adoption of a bleedless or less-bleed architecture – and material choice for the aircraft’s structure.

Composite material for the fuselage has “performance potential”, says Fichefeux, but Airbus needs to determine whether it can reach high production rates and reasonable costs necessary for single-aisle economics.

He adds that the aircraft will also be “more connected, more software-driven” which requires equipment and systems to extract and handle extensive quantities of data.

Fichefeux also points out that crucial decisions need to be made on the level of automation support in the cockpit – potentially employing artificial intelligence – particularly for the “stressful” phases of flight.

“How can I support, automate and assist the pilot in these phases, so that they can focus on piloting rather than managing 10 checklists?” he says. He emphasises that Airbus is still working under the assumption of a dual-pilot cockpit.

Fichefeux says the “jury is still out” regarding the positioning of a next-generation single-aisle in the Airbus line-up, with likely passenger capacity among the multiple decisions yet to be finalised.

But he acknowledges that the A321neo, which has overtaken the smaller A320neo in popularity, would a “good place to start”.

Any successor will need to replicate, or improve upon, the strength of the A320neo family – which has a backlog stretching beyond 2030 – without derailing the vital cashflow for future investment that the current single-aisle generates.

“It’s a very critical decision for the market and for others because it’s our bestselling product,” says Fichefeux. “I think it’s a natural phase in any company to transition between one bestselling product to another.”

Although the A320neo family will continue to be produced “for a very long time”, he states: “There comes, in every company in a situation of success and leadership, a moment to disrupt yourself. And we are exactly in that phase.

“We are in this dual, and not incompatible, [situation] of leveraging the success of the A320 family as long as it takes, while thoroughly preparing the future and being in a position to disrupt it with a much better product. And only once we are convinced we have a much better product will it naturally come.”