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A318 TAKES SHAPE

By Sebastian Steinke

In return, the airline customers benefit from the major advantage of being able to adapt to fluctuations in demand with a single family of aircraft of different sizes. At the same time there are opportunities for considerable cost savings when it comes to spare parts and maintenance and also cockpit crew, a consideration which is becoming ever more relevant these days.

Common type ratings for entire families of aircraft mean not only that pilots can be flexibly deployed between the various models in the manner that best suits the airline's day-to-day operations, but also that any conversion training can be slimmed down or even eliminated altogether, resulting in cost savings that can be considerable.

It is for these reasons that Airbus has decided to develop a new aircraft at the lower end of its product range which will inherit the essential family characteristics of its successful big brothers, the A319, A320 and A321, but with the fewest seats, between 107 and 117.

To keep down the production and maintenance costs, the design specification on which the engineers are working states that up to 95% of parts are to come from the A320 family. Nonetheless, the new 100-seater must be tailored to its market segment while also being as economical to operate as its longer predecessors.

By their nature the fuselage parts, wings and control surfaces which were originally designed for the "large" A320 and then extended for the A321 are rather big and heavy for the smaller A318. But the modular system used throughout the aircraft family reduces manufacturing costs significantly and these savings can be passed on to customers in the form of low selling prices.

Therefore in designing the A318 derivative, Airbus has confined itself to four essential modifications compared with the A319.

To reduce passenger capacity to the desired number of 107 in a multi-class configuration or 117 in a standard single class layout, the fuselage length has been reduced by 4.5 frames or 2.4m. Starting from the fuselage of the A319, which has only one other emergency exit on each side, over the wing, a narrow section of the fuselage fore and aft of the wing has been removed for the A318. But it is precisely here that the cargo door to the baggage compartment is positioned, so that this had to be reduced from 71.5 x 49 inches in the A319 to 50.5 x 49 inches in the A318. This is probably the most labour-intensive design modification for the A318, as the door frame is subject to special structural loads. The dimensions of the new door will still exceed those of the Boeing 737. To preserve the flight stability of the aircraft's very short fuselage, the tail fin had to be slightly raised to improve its effectiveness. As a result the A318 is not just the shortest Airbus but also the highest of the aircraft family members.

And finally, a new, tailored small engine, the PW6122 or PW6124, has been developed. This economical, modern and light turbine was specially designed for the 100-seat market, with fewer compressor stages and fewer parts. But due to its lower power output it will be used on the larger members of the A320 family.

For airlines which already have other members of the A320 series in their fleets, Airbus is therefore also offering the standard larger CFM56-5B/P engine, which powers the A319 through to the A321, as an alternative powerplant for the A318. Its slightly greater weight and marginally higher fuel consumption will then be offset through savings when it comes to holdings of spare parts and maintenance.

"It goes without saying that every aircraft shrink is a compromise on weight," concedes Dr. Gustav Humbert, Chief Operating Officer (COO) at Airbus, during an interview with FLUG REVUE at the Paris Air Show. "We are using the same wing here, so we have to accept a higher wing weight per passenger. This higher weight must not result in loss of performance." Such is the central objective for this new shrink.

One of the major advantages offered by the A318 is the crew commonality, which "makes sense. The variability within the Airbus family lowers airlines' costs."

Versatility which does not stop at the A318, as even this type is being offered in two versions, either with a lower standard weight under 60 tonnes, which is important to qualify for low landing charges, or with a higher kerosene payload resulting in greater weight but additional range. In this way the maximum take-off weight of A318 can be extended from 59t with a range of 2,750km (1,500nm) to 61.5t and 3,700km (2,000nm) or even 66t and 5,200km (2,800nm).

Humbert explains, "Chartered airlines are particularly keen on long range, whereas the scheduled airlines are more interested in keeping this the same as on the A320. And when the airlines want something, we provide it," he says, illustrating a pragmatic approach.

When asked about the future competitors of the A318, especially from Fairchild Dornier, he replies that in some respects the 90-seat design is better from the weight point of view than the A318. But the critical factor here is membership of the same family. "Airlines which are coming from larger-sized aircraft will probably order the A318, whereas those coming from below will no doubt order from Fairchild Dornier." Nevertheless there is an "area of overlap", namely at around 100 seats on trunk routes, i.e. high-frequency, heavily used routes, an area into which smaller aircraft are increasingly moving.

Humbert can also envisage a "corporate jetliner" based on the A318, although as yet there are no concrete plans for a business jet analogous to the A319CJ. All in all, Humbert is quite satisfied with the A380. "The requirement has been solved relatively well," as is reflected ultimately in the excellent sales results - to date around 120 orders have been received.

It is likely that ailing TWA, recently taken over by American Airlines, will cancel its order for the A318, as Airbus CEO Noel Forgeard was assuming at a press conference in Paris, even though legally this order still exists. But if it does, this will not be the end of the world as the Brazilian TAM airline has just placed an order for at least 20 A318's, which should fill any possible gaps.

Meanwhile production of the first parts has already begun: on 21 May the EADS factory in Méaulte, France delivered the first fuselage section to Saint-Nazaire, and final assembly of the first A318 is scheduled to commence in Hamburg on 7 August.

From page 26 of FLUG REVUE 8/2001