It’s no wonder airlines are keen to improve fuel efficiency when fuel is typically one of their largest operating expenses.
According to IATA, the global airline industry’s fuel bill was an estimated US$133 billion in 2016, accounting for a fifth of the industry’s total operating expenses.
Cost isn’t the only factor pressuring airlines into cutting their fuel usage, either; stricter government guidelines are forcing them to think about the environment.
“The aviation sector’s contribution to climate change […] is under increasing scrutiny,” wrote Violeta Bulc, the European Commissioner for Transport, in the 2016 European Aviation Environmental Report. And, a recent report by the Federal Aviation Administration (FAA) says aviation’s contribution to human-induced climate change is also growing. Currently estimated at between 3.5–4.9 percent, aviation’s contribution is forecasted to grow upwards of 6.2 percent by 2050 — unless, as the FAA wrote, “new technologies and policies are adopted to reduce aviation emissions.”
These warnings are a long time in the making. In 2001, the Advisory Council for Aviation Research in Europe (ACARE) released its Vision 2020 report “to confront the competitive pressures imposed on [aeronautics] both by the rapid development of globalization and environmental needs.”
The authors of the report envisioned that, by 2020, the industry would have reduced fuel burn by 50 percent per passenger kilometer compared to the year 2000, and that “the aeronautics sector’s contribution to a sustainable environment is widely understood and appreciated.”
Ron van Manen is Program Manager at the Clean Sky 2 Joint Undertaking, a government-funded European research program to develop technology aimed at reducing CO2, gas emissions and noise levels produced by aircraft. He thinks ACARE’s 50-percent reduction goal from 2001 is still a good touchstone, and believes it can be achieved by improving and optimizing the following:
“We need to work all angles related to the physics of flight,” says van Manen.
Luckily, fresh solutions are already harnessing big data to improve airline operations. Take Safety Line, for example. Company CEO Pierre Jouniaux noticed during his stint as a pilot with Vietnam Airlines that the aircraft’s black boxes provided lots of information about aircraft performance. During this time, he also realized nothing was being done to improve the efficiency of an aircraft’s climb phase.
And so Jouniaux created OptiClimb, a software solution that uses quick access recorder (QAR) data from an individual aircraft’s last 200 flights to calculate the optimum climb trajectory for each flight.
“Until now, the flight management computer has just been using a generic manufacturer model that was the same for any aircraft of one type,” notes François Chazelle, Chief Commercial Officer at Safety Line. “But aircraft go through different things once they’re delivered — engines age differently — and there can be up to 10 percent difference in the performance of two aircraft of the same type.”
Dutch low-cost carrier Transavia was Safety Line’s development partner. “We launched with them in April 2016,” Chazelle explains. “What we’ve seen consistently with them is savings of around 69 kilograms per climb, which basically represents about five percent of the climb fuel on their Boeing 737-800s.
“When you consider that climb will account for 30 percent of the total fuel for medium-haul operations, we’re saving them 1.5 percent of the total fuel cost — about €1 million [US$1.2 million] for each 20 aircraft per year.” At hot and high airports in East Africa, Safety Line has seen 737-800s save of up to 85 kilograms per climb.
In June 2017, the U.S. Energy Information Administration (EIA) published a report stating jet fuel use in the U.S. is lower than it was a decade ago, despite the fact “the number of passengers travelling on U.S. carriers in 2016 was seven percent higher than in 2007.”
The EIA attributed this to airlines right-sizing their fleets and introducing more fuel-efficient aircraft. Bombardier’s C Series is one such new aircraft family focusing heavily on fuel efficiency.
Bombardier claims it delivers a 20-plus percent fuel burn advantage over in-production aircraft in its class. SWISS Airlines introduced the first CS100 to its fleet a year ago, becoming the first airline to introduce both the CS100 and the CS300 — the latter of which was delivered in May 2017 — to its fleet.
Peter Koch, head of the C Series program for SWISS, confirms, “A first analysis of available data samples so far shows an average fuel burn improvement of around 20–25 percent compared to a similar operation with our previous aircraft types (the Avro RJ100 and/or Airbus A319).”
This comes from introducing new materials to the airframe. Alongside an advanced aluminium-lithium fuselage, C Series aircraft also incorporate composite materials used for parts such as the nacelles and wings. Overall, Bombardier estimates this makes a C Series airframe 12,000 pounds lighter than its competitors.
Further weight could also be saved with Panasonic’s eXW wireless IFE system, which delivers branded airline content to passengers’ personal electronic devices using just five line replaceable units. eXW is part of Panasonic’s Connectivity Services, which are included in the C Series Options Catalog.
Another fuel efficiency factor is the Pratt & Whitney PurePower PW1500G engine which was specifically designed for the C Series family.
However, the successful introduction of the C Series to its fleet hasn’t got SWISS resting on its laurels. The airline already has an extensive operational efficiency program in place, which explores future concepts in collaboration with other members of the Lufthansa Group.
Right now, Koch says, “It includes measures such as reduced engine taxi and arrival sequence optimizations among others, all of which are validated through comprehensive data analytics and best practices.”
SWISS pilots are encouraged to exit the runway after landing with only one engine running whenever the situation allows, which the carrier says avoids an estimated 1,500 tonnes of CO2 emissions per year.
The airline’s “Greener Wave” approach procedure — developed with air-traffic control authority Skyguide and Flughafen Zürich AG at Zurich Airport — has now replaced the previously used “first to arrive, first to land” principle. SWISS believes optimized holding patterns is saving the airline a further 1,800 tonnes of CO2 per year.
“Cycles in aerospace are measured in decades, not in years,” — Ron van Manen, Program Manager at Clean Sky 2 Joint Undertaking.
It’s not all roses, though — at least not yet, as van Manen points out. “Cycles in aerospace are measured in decades, not in years,” he says — so results won’t come overnight. “We’re heading in the right direction but will arrive a little bit later than the visionary statement made by ACARE in 2001.”
A more recent cost assessment by the International Council on Clean Transportation (ICCT) in September 2016 concluded airlines could save up to 40 percent of fuel consumption by 2034.
The industry isn’t giving up, though. Van Manen says 2035 onwards is when game-changing technologies created as a result of Clean Sky 2 (running from 2014–2024) will really begin entering the market. At that point, the industry could save an additional four billion tonnes of CO2 by 2050. This is on top of the three billion that more-established Clean Sky technologies are already predicted to save if they’re used as part of new aircraft designs between 2020–2025.
So, which technologies will be the game-changers? “In Clean Sky’s programs to date, one of the flagship efforts has been focused on creating laminar flow on wings and tail surfaces with minute tolerances and roughness,” van Manen says.
“The effect of laminar flow has been known for decades, and glider planes make use of this. But transferring this to the scale of a modern jetliner is a tremendous challenge!” he continues. “Making aggressive use of digitization and new manufacturing methods like additive layer manufacturing (industrial 3D printing) is helping.”
We’re seeing some exciting new engine concepts emerging, where hybrid-electric propulsion or even full-electric propulsion using batteries or fuel cells may make a strong play in future,” van Manen adds.
There’s no one silver bullet, but the aviation industry is certainly doing its best to make sure the future is green.