Future passenger aircraft might not be as exotic as some research projects and artist renderings have suggested, according to Philippe Jarry, a member of Airbus’ strategy directorate. Speaking at a conference in Paris last month organized by France’s Air & Space Academy, Jarry stressed that a number of constraints weigh on aircraft design, limiting the scope for dramatic advances. He also justified Airbus’ apparent procrastination in launching the long-anticipated A320 replacement.
A likely change, for new short- to medium-range aircraft, is speed. Fuel prices and availability will likely prompt manufacturers to design slower aircraft. “If you slow down a bit, you make the trip slightly longer but you save a lot of fuel,” Jarry said. For a one-hour flight, the additional time in the air could be offset by cutting the time the passenger spends at the airport, he added.
A senior member of the Air & Space Academy told AIN that the reduced speed will be probably close to Mach 0.7, rather than the current Mach 0.8 or so. A drawback, however, would be the accompanying lower optimum altitude, he said. It would take the aircraft into more turbulent air, resulting in bumpier rides.
Also subject to evolution is the average size of narrowbodied airliners, whose capacities grew from 102 to 143 seats between 1973 and 2008. Jarry expects the sizes to be in the 155- to 160-seat range by 2028, as a result of the combination of traffic growth, airspace congestion and the need for greater environmental efficiency.
Something that will probably not change is the Mach 0.85 cruise speed for long-haul operations, he said. Because of the way population and wealth are distributed across the planet, most long-haul aircraft fly in east/west directions, rather than north/south. Therefore, they cross a lot of time zones, which added to airport curfews, drives departures and arrival times. “Mach 0.85 enables reasonable timings,” Jarry pointed out.
Also unlikely to change, predicted Jarry, is the general shape of an aircraft. The current tube and wing scheme is very good for conducting ground support
functions when at the gate. Refueling, embarking and disembarking passengers, loading catering, loading and unloading baggage, and servicing the toilets can be performed simultaneously by several vehicles. In this regard, Jarry criticized some futuristic shapes contemplated for new aircraft designs based on blended-wing bodies as being “bags where everything is mixed up.”
Also for a fast turnaround, the size of an airliner needs to be limited, which is an issue Airbus has experienced with the A380. In short, airports can accept few, if any, changes to their infrastructure that might be dictated by the inception of new models.
There also is the long-debated question of alternative types of fuel. A recent Qatar Airways commercial flight between London and Doha proved that replacing conventional kerosene with one made from a gas-to-liquids (GTL) process is quite easy. On that October 12 flight, the Qatari Airbus A340-600’s Rolls-Royce Trent 556 engines were fed by a 50-50 blend of oil-based and GTL kerosenes.
Jarry and other academy members agree that GTL is the most likely path out of the oil era. After 2030, another solution will have to be devised, he said. Hydrogen looks like the most favored contender; however, making it available at every airport would be a major challenge, Jarry added.
In the meantime, the next generation of narrowbody aircraft will have to burn about 40 percent less fuel, he said. “A manufacturer that would not make such a leap would get it wrong,” Jarry asserted. He explained to AIN that, because of the time needed to gather the necessary technologies, 2020 is the earliest possible entry into service for an aircraft that would achieve this goal. He argued that there is no point trying to introduce new aircraft that would deliver smaller fuel-burn savings at an earlier date. “A 12- or 13-percent cut in fuel burn would be easily caught up by an oil price hike,” he contended.
Moreover, Airbus and Boeing already have their hands full with programs like the A350 XWB and 787, respectively. But can operators wait until 2020-24 to get more efficient narrowbodies? According to an academy official, Airbus is seriously working on an A320 replacement and is deliberately keeping it under wraps and playing down market expectations to avoid triggering a reaction from Boeing.