Next Generation Airliners

The first heavier-than-air machine got airborne in 1903 and instantly caught the imagination of the international community although the future implications of the invention were not yet crystallised enough to be gazed through. Exploitation for both military and civil purposes became evident gradually. As could be expected, the military domain grew more rapidly and, inarguably, advances in aerospace for defence applications have been far ahead of the levels manifest in the domain of civil aviation. A noteworthy aspect of the contrast is that combat aircraft have transcended to the fifth-generation and a sixth-generation platform is being bandied about in military circles, implicit to this numerical measurable of generations howsoever diffused be its definition, is the fact that, between generations, there is a noticeable bound to the next level in respect of speed, stealth, manoeuvrability and so on. On the other hand, in the civil aviation domain, the progression has been steady and evolutionary with marginal, incremental changes increasing the speeds, ranges and cabin sizes of successive models and versions. So it is not possible to club characteristics for currently existing airliners and project a quantum jump to a ‘Next Generation’ Instead, what is possible is to look at ongoing developments in the airliner manufacturing industry to pick up trends pointing to future enhancements.

THE SINGLE-AISLE NAROW BODY SPACE

Airbus and Boeing have dominated the single-aisle narrow body space since the 1990s although their names and component companies have changed several times since then. Airbus A320 family and Boeing’s 737 line have had a bitterly contested duopolistic rule globally. Newer versions with some not so substantial improvements and enlargements from both the contenders, have kept the race between them simmering, much to the delight of their customer airlines. However, in the beginning of this century, it started becoming apparent that the marginal increments themselves were becoming progressively smaller. Both were looking for a boon from technology’s munificence to add a big and sizeable improvement to their existing versions. Another interesting aspect of the quest was that extensions of the A320 and the Boeing 737 were tending towards the larger wide body airliners produced by both. Thus the race became one of enhancing existing versions. Both Airbus and Boeing decided that they would work to make the existing versions more cost effective and thus attractive to customers, by replacing the engines on existing A320 and 737 versions and supplementing the engine changes with some other design and material changes. The A320neo and 737 MAX were the new versions with noticeable increments in their performance, but not enough to be called a generation leap.

MIDDLE OF THE MARKET JET

As mentioned earlier, extensions of the A320 and the 737 were tending towards the larger wide body airliners produced by both. Around 2003, Boeing started talking about a Middle of the Market (MoM) jet that would fit snugly between the narrow body and the wide body, filling the intervening gap in passenger capacity and range. The moniker Boeing 797 was also bandied about. Airbus initially ridiculed the idea, but subsequent actions and iterations showed that Airbus was also allured by the idea, not the least because it could not let Boeing be the only one in that space. Boeing perceives the MoM airliner as located somewhere between its largest narrow body (737 MAX9 with 178 passengers and 6,510 km range) and its smallest wide body 787-8 with 242 passengers and 13,621 km range. Airbus would be looking at a competitor between its largest narrow body A321LR (206 passengers, 7,400 km range) and its smallest wide body A330 -800 neo (257 passengers, 13,900 km range). As can be seen from the above coarsely presented statistics, the gap that the MoM is being projected to fill, is not as much for Airbus as for Boeing, Perhaps that is why the first step in this direction originated from Boeing. However, progress in this area is hardly noticeable and may not be consummated by a new “generation” from either of the two contenders.

THE CROSSOVER NAROW BODY JET

While several original equipment manufacturers (OEMs) have offered to the market passenger carriers in the space below the narrow body size, the airline industry utilised aircraft largely in the 120 plus category for “full scale carriers” and 50 plus seaters (jets and turbo props) for “regional” operations. Around a decade and a half ago, Embraer with its single-aisle EJets family, served to diffuse that distinction somewhat by optimising for that intervening space. Bombardier followed with CSeries family in the same space. This segment is now being increasingly referred to as the Crossover Narrow Body Jet and is loosely defined as a jet airliner with 70 to 150 seats. It is perceived as filling the space between the higher end of regional aircraft and the lowest strata of the single space narrow body jet. The significance of this segment becomes noteworthy when seen in the recent moves by Airbus and Boeing to cuddle Bombardier and Embraer respectively with the specific purpose of controlling and promoting the EJets and the C Series correspondingly while ensuring they do not dent their market strengths. Nonetheless, the Crossover Narrow Body Jet does not represent a “generation” change but merely serves to fill a gap that existed below the narrow body space.

SUPERSONIC AIRLINER

The idea of supersonic passenger airliner originated in the 1960s and the first supersonic airliner to enter passenger service, the Concorde, carried out its inaugural commercial flights on January 21, 1976, with Air France and British Airways. Only 20 editions were built in all and, due to the overall pressures on airlines and rising cost of aviation fuel, its appeal faded rapidly and the last supersonic passenger service was flown on October 24, 2003. The only other supersonic airliner to enter service was the Russian Tu-144 and at no time did the total number of supersonic airliners in service ever exceed 30. However, a more sophisticated supersonic airliner is likely to debut in the near future with developments afoot in the United States (US), Russia and Europe. Notable US programmes are firstly, National Aeronautics and Space Administrtion’s (NASA’s) QueSST and secondly, Virgin Group’s tie up with Boom Technology to produce XB-1. QueSST (Quite Super Sonic Technology) is toiling hard to eliminate the sonic boom sound or at least reduce it to acceptable levels and is expected to fly at speeds of Mach 1.4 (around twice the speed of today’s commercial airliners) and carry up to 120 passengers over 9,200 km while the Boom aircraft is being designed to be a 50-seater capable of a Mach 2.2 cruise over 7,400 km. The Boom XB-1 is expected to consume three times the fuel per seat mile than current options over long haul sectors; there is thus a shadow over its commercial viability. Russian news sites have reported Russian plans to produce a huge supersonic cargo plane called the Perspective Airborne Complex of Transport Aviation (PAKTA) capable of flying at Mach 1.6 and carrying up to 180 tonnes over a range of 7,000 km. While the US programmes are a couple of years away from first flight, the Russian programme may fructify only by 2030. European company Airbus obtained a US patent in 2015 for an “ultra-rapid air vehicle” designed to fly at Mach 4.5. The aircraft design envisages a takeoff like a conventional plane using ordinary turbojet engines; once it is airborne, an open door in the stern of the plane reveals a rocket motor which starts and sends the aircraft into a near vertical trajectory, accelerating it to supersonic speeds. However, with its unconventional fuselage (a thick delta wing swept back to around 75 degrees) and a passenger cabin with only 24 seats, this model will require major tweaking to be of commercial value. Similarly, other European designs e.g. Long Term Advanced Propulsion Concepts and Technologies (LAPCAT) programme launched by European Commission are still far away from fruition, as compared to those from the the US ones. When the supersonic airliner flies commercially in a three to five years from now, a “generation” jump may be said to have taken place (although cynics could still play spoilsport by recalling the Concorde and the Tu-144 programmes of yore).

CONCLUSION

Boeing’s ambition to provide autonomous passenger airline flight is a programme to watch out for. The idea is to see whether passenger carriage can be undertaken with a single pilot or even with no pilot on board while maintaining commercially acceptable safety levels as well as satisfying passengers and insurers! Possibly, a pilotless, trans-oceanic, passenger flight would really qualify to be a “generation” leap. Meanwhile, airliner evolution trudges on at a leisurely pace; discounting the jump to supersonic speeds, the probability of an enhancement in design, material or configuration so radical as to be describable as a generation jump looks remote.