The EconomistJune 1st 2019 Technology Quarterly |Aviation 52
1fierce. The jurisdictions in which they op-
erate are each acutely aware of any knavish
tricks by the authorities in the other in-
tended to support the home team, and are
willing to challenge such arrangements in
the World Trade Organisation. All this
helps drive technological improvements.
In the case of airframes, the biggest
technological shift going on is an invisible
one, from metal alloys to composite mate-
rials—mostly cfrps. The a350’s airframe is
53% composite. The resulting lighter
weight, Airbus claims, makes it 25% more
efficient, in terms of fuel consumption,
than predecessor planes. That is a huge
saving for the world’s airlines. According to
the International Air Transport Associa-
tion, an industry body, fuel accounts for al-
most a quarter of airlines’ operating ex-
penses—$180bn in 2018.
Boeing, naturally, matches these claims
with claims of its own. The Dreamliner is 50% composite—and
again around 20% more efficient than its predecessors. Compos-
ites bring advantages beyond lightness. Unlike metals, they do not
corrode. Nor do they crack from metal fatigue. They therefore need
less maintenance. They do bring problems, though. One is that
damage to them is less obvious than to metal, because they do not
bend or dent. This is one reason why Airbus fits hundreds of sen-
sors, ranging from voltage meters to strain gauges, all over its
a350s. These can warn of problems invisible to the eye. Another
disadvantage of composites is that they are not as malleable as
metals. Bit by bit, however, that disadvantage is disappearing.
Parts made of composites are constructed by a process called
laying up. This builds a component from ribbons or small sheets of
carbon-fibre fabric applied to a forming mould together with a res-
in that hardens when the whole thing is baked in an autoclave.
Originally, laying up was done by hand. Then automatic tape-lay-
ing machines made things faster and more reliable. These days,
matters have improved still further. Giant looms are used to weave
carbon-fibre ribbons into huge sheets. These looms can vary the
tension in warp and weft in a way that does the job of the forming
mould, creating sheets that reflect from the start the shape of the
component of which they will become part. This makes laying up
much easier, speeding up production even more.Now boarding
In civil aviation, that speeding up of production is going to be cru-
cial. Airbus, in a forecast published in 2017, predicted that air traf-
fic will grow at 4.4% a year over the next two decades, requiring
some 36,600 new passenger and 830 cargo aircraft at a total value of
$5.8trn (see chart). Boeing’s forecasts are, if anything, more bull-
ish: a 4.7% annual growth in traffic, more than 41,000 new aircraft
and a total value of $6.1trn.
To meet such demand, both firms will need to up their game,
and they are doing so. Oliver Wyman, a consultancy, said in a re-
port last year that it expected production of Airbus’s a320 and Boe-
ing’s 737 each to jump from around 40 a month in 2015 to 60 a
month this year. Those figures may need to be adjusted a bit after
the recent 737 accidents, but the trend is clear.
Techniques like using looms to improve the
manufacture of parts contribute to this growth. But
grander plans are afoot. According to Grazia Vitta-
dini, Airbus’s chief technology officer, the key to the
future is connectivity.
It would be easy to dismiss that as a buzzword in-
vented by the marketing department if it were not
for all those sensors aboard every a350. The 30 giga-bytes of data they transmit every day—and
similar, if not quite so abundant, quanti-
ties of data from other types of Airbus air-
craft—are the basis of a system called Sky-
wise that allows both the firm and its
customers to track what is going on across
entire fleets of aircraft.
Eventually this will lead to every plane
having an electronic twin on the ground.
This system is already established for jet
engines. Manufacturers create a computer
model of each engine they make, and then
update it during or after every flight, using
data collected by sensors on board the real
thing. That way, the electronic simulacrum
can keep an eye on its physical counter-
part, flagging up potential problems and
predicting better than an arbitrary mainte-
nance schedule when parts need replacing.
What works for engines can easily be ex-
tended to entire aircraft—and even to a
time before an individual plane is born, tracking its components
as they are put together. This way, the process of assembly can be
monitored, integrated and speeded up.
Further off into the future, plans for new generations of aircraft
are already being laid. There is talk, for example, of cfrps having a
serious makeover. The resins currently used to bind the sheets and
tapes of fibre together are what are known as thermosetting plas-
tics. Once baked, these hold their shape for ever. Most of the mate-
rials that a layman would think of on hearing the word “plastic”,
though, are different from this. They are thermoplastics, and can
be softened by heating and then remoulded an indefinite number
of times. They behave, in other words, like metals. And, like met-
als, they can be riveted—a process easier than assembling things
using lock-bolts. They can also be recycled, which saves money
and burnishes a firm’s green credentials.Natural fabrics
Looking even further ahead than that, Airbus is now experiment-
ing with spider silk, produced on an industrial scale by genetically
modified micro-organisms, for making aircraft components. Such
silk is stronger, tougher and lighter than almost any man-made
material. Work on it is still at an experimental stage. But Airbus is
collaborating with amsilk, a German biotechnology firm, to devel-
op silk-reinforced polymers that might one day become substi-
tutes for cfrps.
As to the design of airframes themselves, cautious improve-
ment rather than radical change is the order of the day. No one has
forgotten the lesson of the Sonic Cruiser. Though the design for
that unbuilt aircraft retained a cylindrical fuselage for passengers
to sit in, it had delta wings aft and a pair of canards at the front for
stability. It would, as the name suggests, have cruised at Mach
0.98, just below the speed of sound.
It bombed. No one wanted it, mainly because its fuel consump-
tion would have been too high (most passengers seem to prefer
cheap tickets to speedy arrival). There was also a problem with its
awkward shape, which would have made it difficult to fit into the
existing infrastructure of global airports.
That does not mean that the design of air-
frames—and wings, in particular—cannot be im-
proved. In January, for example, Boeing announced
it was working on a proposal that will change the
look of aircraft quite a lot if it is implemented. The
Transonic Truss-Braced Wing, as the firm calls it,
will have a pair of wings fixed above the fuselage,
each supported by a brace that is fixed below the fu-
selage. This arrangement allows the main wings toThe world takesflightSource: Airbus*Passengeraircraftwith100+seatsandfreighteraircraftabove
ten tonnes †FormerSovietUnion,excludingBalticstatesGlobal aircraft fleet*,’00001020304050LatinAmerica2018 2037, forecastAsia-PacificNorth AmericaEuropeMiddle EastCIS†AfricaAirbus is now
experimenting with
spider silk for making
aircraft components