GREENAIR NEWSLETTER 28 APRIL 2017
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JetBlue and Boeing see exciting future in passenger hybrid-electric aircraft and invest in start-up Zunum
Fri 28 Apr 2017 – US carrier JetBlue and Boeing are to back start-up Zunum Aero, which is developing regional hybrid-electric aircraft that could be flying as early as the 2020s. Hybrid aircraft could revolutionise the regional airline market, say the partners, by bringing about cheaper, faster and more environmentally-friendly air travel between regional airports. Both Boeing and Airbus are already working on the concept themselves but the technology breakthrough is dependent on major advances in battery power, as well as aircraft and engine design. Initially, Zunum is planning a small capacity aircraft with a range of 700 miles but by 2030 it expects to be producing aircraft accommodating up to 50 passengers and capable of flying over 1,000 miles. Another US start-up, Wright Electric, also has ambitions to come up with an electric passenger aircraft within the next 10 years and is being supported by UK budget airline easyJet.
Zunum says there is a network of over 5,000 underutilised regional and general aviation airports in the United States alone, and using hybrid-electric aircraft would enable “a golden era of fast and affordable electric air travel, reversing the 70-year consolidation of air services.” It believes a regional electric air network will offer a fast, flexible and affordable alternative to busy highways and high-speed rail, operating point-to-point and as feeders to hub airports.
It claims the impact of its hybrid-electric aircraft on door-to-door travel times on busy corridors could be a reduction of 40%, and by as much as 80% on less trafficked routes; much lower operating costs, enabling fares 40-80% below current prices; 80% lower emissions, dropping to zero over time as battery densities improve; and a 75% drop in community noise, opening up all-hours access to smaller airports.
Three years into development, the company has already multiple patented technologies in place. It says it has an experienced, multidisciplinary team across aircraft, aircraft engines and electric vehicles disciplines working on the project, including leaders of two flying electric vehicle programmes and the leader of a NASA-funded programme on drives for electric airliners. The team has also been engaged with the FAA since 2014 to drive development of certification standards for electric aircraft.
With a PhD in mechanical and aerospace engineering from Cornell University, Zunum Aero’s founder and CEO, Ashish Kumar, spent his early career as Professor of Engineering at Brown University and as research fellow at Sandia National Laboratories. He has a working background with Microsoft, Google, Dell and McKinsey, before helping to launch aviation electronics marketplace Aeroxchange.
“The shift of the industry to large aircraft and long ranges driven by gas turbines has concentrated almost all air traffic to just 2% of our airports, creating a massive transport gap over regional distances where there is no high-speed alternative,” said Kumar. “As a result, door-to-door times for most journeys are no better than they were 50 years ago.
“Hybrid propulsion is an industry-changing solution, enabling mid-sized aircraft on regional routes to have better cost efficiencies than airlines.”
The venture is being backed by JetBlue Technology Ventures, a wholly-owned subsidiary of the airline that was set up last year to invest in and partner with early stage start-ups “at the intersection of technology, travel and hospitality to improve the entire travel experience.”
Said its President, Bonny Simi, who is now on Zunum’s Advisory Board: “Our goal is to be part of a disruptive force rather than the one being disrupted and we seek new technologies that look to change the game. As a company that is also deeply committed to innovation in sustainable travel, we believe that Zunum and its quiet, environmentally-friendly aircraft will light up a vast network of underutilised airports and reinvent regional travel.”
Boeing’s innovation cell, Boeing HorizonX, said it was investing because it believes Zunum was leading the market in hybrid-electric development.
“This technology and customer approach has the potential to transform the market for small, short-haul aircraft that can use smaller regional airports,” commented its Vice President, Steve Nordlund.
Warren Christie, JetBlue’s SVP Safety, Security and Training, and Logan Jones, Managing Director of Boeing HorizonX, have joined the Board of Zunum.
Just a year old, Wright Electric has not as yet managed to attract the same level of industry investment and backing but has received support from UK-based budget airline easyJet.
“Easyjet has had discussions with Wright Electric and is actively providing an airline operator's perspective on the development of this exciting technology,” the airline told the BBC.
It is planning a much bigger aircraft than Zunum, capable of carrying 150 passengers, but with a shorter range of 300 miles, although how the aircraft will be powered is dependent on advances in battery technology, says Wright. If slower than anticipated then initially a hybrid-electric version would be the result rather than all-electric.
The company said it has hired a team previously funded by NASA to investigate the potential for electric planes that puts it ahead of the competition. Co-founder Jeff Engler gave a presentation last month to potential investors at Y Combinator’s Demo Day.
The company has a goal for every short flight to be electric within 20 years, but a report in the Independent newspaper quotes an airline pilot who said all-electric short flights by 2037 was “fanciful”.
Meanwhile, Aviation Week magazine reports that as a result of rapid progress in electric propulsion, Airbus has dropped plans to produce the E-Fan family of light aircraft in favour of a larger and more powerful aircraft called E-Fan X, which could be flying in the next three years. Airbus and Siemens signed a collaboration agreement in April 2016 to demonstrate the feasibility of hybrid-electric propulsion by 2020, with their sights set on developing a commercial aircraft with less than 100 seats that could enter service by 2030.
ACI Asia-Pacific recognises airports in the region for their environmental and carbon reduction achievements
Fri 28 Apr 2017 – The inaugural annual Green Airports Recognitions were presented during this year’s ACI Asia-Pacific Regional Assembly held recently in Doha, Qatar, with Platinum recognitions going to Kuala Lumpur International Airport (KLIA) and Darwin International Airport. ACI Asia-Pacific stresses these are not competitive awards but are recognition of environmental projects undertaken by airports large and small in the region. The objective is to promote environmental best practice and recognise outstanding accomplishments. Understanding that different airports have different environmental priorities, each year a specific environmental aspect will be chosen as the recognition theme. This year’s theme was energy management. Also during the Assembly, 11 airports in the region were presented with their Airport Carbon Accreditation certificates to recognise their initiatives and achievements in carbon reduction.
A total of 16 submissions were received from airports across Asia, Australasia and the Middle East for the Green Airports Recognition 2017. In the category for airports with 25 million annual passengers and above, Platinum recognition went to KLIA, Gold to New Delhi Indira Gandhi International Airport and Silver to Hong Kong International Airport (HKIA).
KLIA first established an energy management policy in 2012 with the main objectives being to improve energy consumption efficiency, reduce utility cost, optimise capital expenditure for energy efficiency and strive to become a world-class energy management airport. A 14 MW photovoltaic (PV) solar power system has since been installed on the rooftops of a satellite building and the long-term carpark. It contributed 55,857 MWh of electricity between January 2014 and November 2016, representing a reduction of 41,390 tonnes of CO2 emissions.
Delhi was the first Asia-Pacific airport to achieve status as carbon neutral under the Airport Carbon Accreditation programme and the first airport globally to receive ISO 50001:2011 accreditation, which specifies requirements for establishing, implementing, maintaining and improving an energy management system. Energy management is responsible for 26% of the airport’s overall operating costs and it has implemented a programme that has seen a 12% reduction in energy consumption of its HVAC system.
Airport Authority Hong Kong (AAHK), which operates HKIA, has developed a multi-dimension energy management programme to enhance energy efficiency at the airport. As a result, carbon intensity has been reduced by 25.6% from a 2008 baseline despite an average annual increase in airport throughput of 4.5%. In November 2016, AAHK set a new pledge to further reduce the airport-wide carbon intensity by 10% by 2020 based on 2015 levels.
In the category for smaller airports – those with annual passengers less than 25 million – the Platinum recognition for Australia’s Darwin International Airport was as a result of a long-term commitment by its authority, Northern Territory Airports, to using renewable energy. The Darwin Airport Solar Project was developed in two stages, resulting in a 5.5 MW facility believed to be the largest airside PV solar facility in the world. It generates 25% of the airport’s overall energy needs, meets 100% of the daily peak demand and has reduced carbon emissions from stationary energy by 25%.
Gold recognition went to Adelaide Airport, which has also installed a solar PV installation. It completed construction of a 1.17 MW system on the multi-level carpark roof in March 2016, the largest rooftop system, and second largest overall, in South Australia. It is also the largest rooftop installation at any Australian airport and one of the largest private, commercial arrays of any kind in the country. It is expected to generate 1.73 MWh per year, equating to around 10% of total electricity consumption by the airport.
Amman’s Queen Alia International Airport (QAIA) received Silver recognition for a two-year runway lighting project completed in December 2016 to replace halogen units with LEDs. In addition to becoming just the second airport in the region to have a LED-lit runway, other environmental initiatives have resulted in reductions in carbon emissions of 495 tonnes and electricity consumption by 779,454 KWh annually.
“I wish to congratulate not only the recognised airports but all the participated airports because their partaking helps exemplify the spirit of this recognition, which is to promote best practice sharing among airports,” said Patti Chau, ACI Asia-Pacific Regional Director.
Originally developed and launched by ACI Europe in June 2009, the Airport Carbon Accreditation programme was extended to airports in ACI’s Asia-Pacific region in November 2011, and since then 38 airports have been certified. As well as New Delhi Indira Gandhi International, three other airports – Hyderabad Rajiv Gandhi International, Bangalore International and Australia’s Sunshine Coast – have achieved the highest carbon neutrality (Level 3+) level of the programme.
“Airports in our region have made remarkable progress in their journey towards carbon neutrality,” commented Chau at the Assembly. “We are proud of the 38 Asia-Pacific carbon accredited airports, which account for more than 29.5% of air passenger traffic in Asia-Pacific. Going forward, we will continue to encourage airports to establish targets on carbon emissions reduction and work with our members to achieve sustainable growth and join the 189 airports worldwide in becoming accredited airports.”
ACI Asia-Pacific’s Regional Environment Committee has elected for the period 2017-2018 Jakrapop Charatsri of Airports of Thailand as its new Chair, taking over from Mike Kilburn of HKIA, and Wendy Weir of Brisbane Airport Corporation (BAC) as Vice Chair. Charatsri was the founding Chair of the ASEAN International Airports Association’s Environmental Working Group and Weir is BAC’s Environment and Sustainability Manager.
Air Canada and NRC start research into biofuel impact on contrail formation from commercial flights
Tue 25 Apr 2017 – Five Air Canada biofuel-powered flights between Montreal and Toronto over the coming days will be trailed by a National Research Council of Canada (NRC) T-33 research jet using advanced sensing equipment to sample and test the contrail biofuel emissions from each aircraft. It is part of the Civil Aviation Alternative Fuel Contrail and Emissions Research (CAAFCER) project led by NRC that is studying the environmental benefits of biofuel use on contrails. Depending on suitable weather conditions required for the testing, the first of the flights could take place today. The sustainable biofuel has been produced by AltAir Fuels from used cooking oil and supplied by SkyNRG. NRC has already taken part in extensive trials of a NASA-led project in the United States to measure the impact of alternative fuels on contrails, details of which were recently published in the journal Nature. The results showed using biofuels could substantially decrease jet engine exhaust particles and so reduce climate-warming contrails.
The research being undertaken on the CAAFCER project is different, explained an Air Canada member of the project team, and will be more focused on the particle emission contrail formations that lead to cirrus cloud formation and radiative forcing. Compared to the NASA project flights, which involved test aircraft, the T-33 trailing the Air Canada commercial flights will fly further back and, importantly, bring back data that is more representative of everyday flying, she said.
Added Anthony Brown of NRC’s Flight Research Laboratory and the T-33 pilot: “We will also be obtaining contrail and emissions data in the Great Lakes atmospheric environment, a region so much under the influence of the Northern jet stream and one in which we have already measured higher growth rates of contrail ice particle sizes using our T-33.”
NRC has built up extensive experience in flight testing alternative aviation fuels. In October 2012, the agency undertook the first-ever flight of a civil jet aircraft powered by an unblended biofuel (see article). Supplied by Canadian company Agrisoma, the fuel was produced from Brassica carinata, a sustainable non-food oilseed crop grown in Western Canada.
Jerzy Komorowski, General Manager of NRC’s Aerospace portfolio believes the important CAAFCER research would further reveal the viability of biofuels. “By contributing our unique T-33 research aircraft specialising in contrail data collection and our expertise in emissions analysis, we hope to provide key information towards biofuel inclusion in all future flights.”
Although details have not yet been released, the biofuel blend to be used by the Air Canada flights will be the highest possible that can be certified, said the airline, possibly between 40-45%. The aircraft will be defueled of conventional fuel before being uplifted with the biofuel blend into both engines. The project is not aircraft or engine dependent and the likelihood is the flights will involve Airbus A320 family aircraft as that is the most commonly used on the route by the airline.
“We are pleased to support Canada’s research on the additional benefits of aviation biofuel. This project is an important step in furthering the industry’s understanding of how biofuel reduces aviation’s carbon footprint and overall environmental impact,” said Teresa Ehman, Director, Environmental Affairs at Air Canada. “Air Canada recognises its environmental responsibilities and the importance of understanding and integrating environmental considerations into our business decisions.”
The CAAFCER project involves six stakeholder organisations, with primary funding from the Green Aviation Research and Development Network (GARDN), a non-profit organisation funded by the Business-Led Network of Centres of Excellence of the Government of Canada and the Canadian aerospace industry. It also has further financial support from NRC and the enabling support of Air Canada ground and flight operations. Other partners in the project include Boeing, SkyNRG, University of Alberta and Waterfall.
Air Canada and NRC are also participating in Canada’s Biojet Supply Chain Initiative (CBSCI), a three-year collaborative project, also primarily funded by GARDN, which started in 2015 and is aiming to introduce 400,000 litres of sustainable aviation biofuel into the shared fuel system at Montreal Airport and create a Canadian supply chain of sustainable fuels using renewable feedstocks (see article).
Update Tue 25 Apr:
The first flight took place today as planned. NRC’s Anthony Brown reported excellent results were obtained by the T-33 trailing an Air Canada Airbus A320 biofuel flight from Montreal to Toronto, which measured persistent and spreading contrail. The second flight is anticipated on Thursday.
CORSIA aviation carbon emissions scheme must learn lessons from UN’s flawed offset mechanism, says study
Tue 25 Apr 2017 – While ICAO deliberates over rules concerning what offsets should be eligible under its carbon scheme for international aviation, a study prepared for the European Commission concludes the UN’s Clean Development Mechanism (CDM) has fundamental flaws in terms of overall environmental integrity. An offset mechanism established under the Kyoto Protocol to contribute to GHG mitigation, the CDM will end in 2020 – just as the ICAO CORSIA scheme gets underway – and a future design is required under the successor Paris Agreement. The fundamental principle that only real, measurable and additional emission reductions are generated, has not been adequately followed in most of the projects covered by the CDM, finds the study by Öko-Institut. Lessons should be learned and applied to other crediting mechanisms like CORSIA, it advises. NGOs, meanwhile, say ICAO runs the risk of repeating the mistakes and the aviation sector should not rely on offsetting to address aircraft emissions.
With almost 7,700 CDM projects and more than 1.6 billion Certified Emission Reductions (CERs) units or credits issued, the UN mechanism has developed into a vital component of the global carbon market and will form an important basis for future mechanisms. The key feature of such a policy is that the credited and transferred emission reductions should not have occurred in the absence of the mechanism. The ability to deliver such a result depends heavily on having a reasonably effective way to assess additionality both for specific project types and on an aggregate basis, and to set a baseline such that the number of credits issued does not, in total, exceed actual reductions. However, says the study, demonstrating additionality and setting baselines are the areas of most concern with the CDM and it has been difficult to implement reliable assessment methods.
Öko-Institut estimates around 85% of the covered projects and 73% of the potential CER supply have a low likelihood of ensuring environmental integrity, defined as ensuring emission reductions are additional and not over-estimated. Only 2% of the projects and 7% of potential CER supply analysed have a high likelihood of ensuring environmental integrity.
Most energy-related project types (wind, hydro, waste heat recovery, fossil fuel switch and efficient lighting) are unlikely to be additional, claims Öko, mainly because the revenue from the CDM for these project types is small compared to the investment costs and other cost or revenue streams, even if CER prices – currently less than €0.50 per metric tonne – would be much higher than today.
Öko says that compared to earlier assessments of the environmental integrity of the CDM, its analysis suggests the mechanism’s performance as a whole has not improved over time, despite enhancements of a number of CDM standards. The main reason for this is due to a shift in the portfolio towards projects with more questionable additionality. It accuses the Executive Board that oversees the CDM of simplifying rules that have had the effect of undermining integrity, such as introducing ‘positive lists’ for many technologies where additionality is questionable, and failing to exclude project types with a low likelihood of additionality.
However, concedes Öko, the CDM has provided many benefits. “It has brought innovative technologies and financial transfers to developing countries, helped identify untapped mitigation opportunities, contributed to technology transfer and may have facilitated leapfrogging the establishment of extensive fossil energy infrastructures,” say the authors of the study, which was also contributed to by the Stockholm Environment Institute and INFRAS. “The CDM has also helped to build capacity and raise awareness on climate change. It also created knowledge, institutions and infrastructure that can facilitate further action on climate change. Some projects have provided significant sustainable development co-benefits.”
Despite these achievements, and with well over a decade of considerable experience, “the enduring limitations of GHG crediting mechanisms are apparent,” they add.
The future role of crediting mechanisms should be revisited in the light of the Paris Agreement, advises the study. However, the context for their use has been fundamentally changed as a result of all countries now having to submit mitigation pledges under their Nationally Determined Contribution (NDC). Much of the current CDM project portfolio will fall within the scope of NDCs, which has implications for double-counting of emission reductions.
Although few countries have so far indicated they intend to use international credits to achieve their mitigation pledges, an important source of demand will come from the aviation sector under CORSIA. Avoiding double-counting with emission reductions under NDCs will be a challenge that is similar to that of avoiding double-counting between countries, observes the study. Parties to the Paris Agreement should ensure integrity of international transfers of mitigation outcomes, advise the authors. “The includes robust accounting provisions, inter alia, to avoid double-counting but should also extend to other elements, such as comprehensive, transparent and ambitious mitigation pledges as prerequisite to participating in international mechanisms.”
As part of fundamental and far-ranging changes to the CDM, the study recommends limiting the mechanism to project types that have a high likelihood of delivering additional emission reductions. However, as far as Öko is concerned, this would therefore strike out most energy projects, which form the majority of the CDM portfolio. This also has implications for Chinese support of CORSIA. Almost two-thirds of the potential CER supply in the period 2013-2020 is expected to be provided by CDM projects in China.
Öko also recommends focusing climate mitigation efforts on forms of carbon pricing that do not rely extensively on credits and on measures such as results-based climate finance that do not necessarily serve to offset other emissions. CERS, for example, could be purchased and cancelled as a form of results-based climate finance, rather than using them for compliance towards meeting mitigation targets.
“Our findings suggest that crediting approaches should play a time-limited and niche-specific role, where additionality can be relatively assured, and the mechanism can serve as a stepping stone to other, more effective policies to achieve cost-effective mitigation,” concludes the study.
Brussels-based Transport & Environment points out the EU no longer allows its member states after 2021 to use offsets when meeting their 2030 climate targets. “Yet at the same time, Europe is now endorsing an approach at ICAO to address international aviation emissions using potentially the same approach that this report so thoroughly discredits,” it said in a statement. Relying almost exclusively on CORSIA to address Europe’s “soaring” aviation emissions was an inherently risky strategy, it said, and represented special treatment for the carbon-intensive sector.
“This study is a wake-up call to the world that relying solely on offsets to address aviation’s climate impact is unsustainable,” said T&E Aviation Manager Andrew Murphy. “The EU must, at a minimum, ensure the worst offset projects are excluded from the ICAO scheme to avoid greenwashing by the airline industry, the fastest growing source of greenhouse gas emissions.
“Offsets won’t solve aviation’s climate problem – instead the EU needs to pursue policies such as fuel taxation, ending subsidies, reforming the EU ETS and ceasing support for airport expansion.”
Another climate NGO, Carbon Market Watch, said the study added to a growing body of evidence that showed manifold problems with using carbon offsets.
“These new findings are not surprising but they are another reminder that carbon offsetting has not worked as a reliable climate tool,” said Aki Kachi, International Policy Director. “The CDM and the emissions shifting concept of offsetting are not fit for the climate challenges ahead – the Paris Agreement’s changed policy landscape calls for a new approach to international climate cooperation.”
Added Aviation Policy Officer Kelsey Perlman: “It’s baffling to think that the aviation industry could potentially use credits that do nothing to compensate for their rapidly growing climate impact. To avoid greenwashing, aviation’s new offset market has to exclude credits that have not proven to be effective.”
Speaking on behalf of the industry at the ERA Regional Airline Conference in Copenhagen last month, Michael Gill, Executive Director of the Air Transport Action Group, said the CORSIA market-based measure scheme was one of four pillars that formed the industry's strategy to meet its climate goals, which also included the development of new technology, including sustainable alternative fuels, operational improvement measures and better use of infrastructure. However, he said, CORSIA was a fundamental part of the industry’s climate action plan and would help achieve its medium-term target of carbon-neutral growth from 2020. Getting the political consensus from 191 countries to sign up to the ICAO agreement on CORSIA had been no small undertaking, he said. “While it wasn't the perfect agreement for all parties, we should recognise it was a significant achievement.”
Ongoing work on the technical aspects of the scheme was taking place in an extremely positive fashion, he reported. “For it to be successfully implemented there are two essential parts remaining to be done,” he said. “Firstly, the work on the monitoring, reporting and verification (MRV) of CO2 emissions. It is vital to the credibility of CORSIA how operators measure their emissions and how that information is then processed.
“The second area of work is determining the environmental integrity of the scheme. It is fundamental that the offsets airlines purchase demonstrate actual carbon reductions. From our perspective, and I'm sure from that of NGOs, it is clear that we want to see high quality carbon offsets, at a level that will meet the demand for airlines around the world and which will bring about real environmental gains.”
The Öko study was originally published in March 2016, well before ICAO states reached agreement on CORSIA at their Assembly last October, but has only now been released by the European Commission’s Climate Action directorate (DG CLIMA).
Also speaking at the ERA conference, Laurence Graff, Head of DG CLIMA’s international carbon market, aviation and maritime unit, said the ICAO agreement was a good outcome and a good start.
“Carbon neutrality from 2020, however, is in our view not sufficient but the scheme has a review mechanism that should allow for ambition to be enhanced over time and made consistent with the Paris Agreement,” she said. “We still have a lot on our plate to turn CORSIA into reality. Without extremely important rules on, for example, transparency and the quality of offsets we would not be in a position to know whether the scheme will be effective and truly deliver what it is supposed to.”
She said there was a difference in the level of climate ambition between Europe’s own carbon trading scheme for aviation, the EU ETS, and CORSIA, and the Commission will be reviewing how best to reconcile and maximise the benefits of the two schemes, while minimising the administrative burden and avoiding duplication.
Negotiations on the role of carbon market mechanisms under the Paris Agreement reconvene next month at the UNFCCC intersessional in Bonn, Germany. Also next month, ICAO is holding a seminar in Montreal that aims to share information on the design elements of CORSIA and implementation aspects, as well as the outcome from a series of regional seminars on CORSIA for ICAO states that recently concluded.
Incidents of severe aircraft turbulence likely to multiply as a result of climate change, finds study
Wed 12 Apr 2017 – Incidents of severe aircraft turbulence on transatlantic routes are likely to become twice or even three times more common as a result of climate change, finds a new study from the Department of Meteorology at the University of Reading in the UK. The study used supercomputer simulations of the atmosphere to calculate how wintertime transatlantic clear-air turbulence would change at an aircraft’s cruising altitude of around 39,000 feet (12 km) in response to a doubling in the concentration of CO2 levels in the atmosphere, which scientists predict will occur later this century. The results show the average amount of light turbulence increasing by 59%, rising to 149% for severe turbulence. A significant number of injuries to passengers and crew already take place each year, as well as damage to aircraft, and the study concludes an intensification of clear-air turbulence could have important consequences for aviation.
Climate scientists predict the midlatitude jet streams in both the northern and southern hemispheres are expected to strengthen at aircraft cruising altitudes as the climate changes, leading to stronger vertical windshears within the jet stream. The windshears can become unstable and are a major cause of turbulence.
Previous climate modelling studies have indicated that the amount of moderate-or-greater clear-air turbulence on transatlantic flight routes in winter will increase significantly in future as the climate changes. This new research examined five different turbulence strength levels, to investigate how they will each change in future. The results show that the average amount of light turbulence in the atmosphere will increase by 59% (a range of 43%-68%), with light-to-moderate turbulence increasing by 75% (39%-96%), moderate by 94% (37%-118%), moderate-to-severe by 127% (30%-170%) and severe by 149% (36%-188%).
“Our new study paints the most detailed picture yet of how aircraft turbulence will respond to climate change,” said Dr Paul Williams, who conducted the research. “For most passengers, light turbulence is nothing more than an annoying inconvenience that reduces their comfort levels, but for nervous fliers even light turbulence can be distressing.
“However, even the most seasoned frequent fliers may be alarmed at the prospect of a 149% increase in severe turbulence, which frequently hospitalises air travellers and flight attendants around the world.”
A paper published in 2002 indicated 790 turbulence encounters by scheduled US carriers over the course of a year that resulted in 687 minor injuries and 38 serious injuries to flight attendants, along with 120 minor injuries and 17 serious injuries to passengers. However, Williams says typical rates are likely to be much higher because of under-reporting and other estimates show there are over 63,000 encounters with moderate-or-greater turbulence and 5,000 encounters with severe-or-greater turbulence annually.
Unlike turbulence in the weaker categories, severe turbulence does pose a safety risk to passengers and crew because it causes aircraft to execute random motions with vertical accelerations that exceed the gravitational acceleration and therefore arguably warrants separate consideration, says this new study, which is published in the journal Advances in Atmospheric Sciences.
There are also the economic costs from turbulence that arise from injuries, damage to airframes and cabins, flight delays, inspections, repairs and post-incident investigations. These costs have been estimated by Williams to be as high as $200 million annually for US carriers alone.
Currently, the median length of a patch of turbulence is around 60 km, which equates to about five minutes of flying time, and the median thickness is about 1 km, and this limits the effectiveness of altitude change as an evasive manoeuvre.
However, points out Williams in his paper, the projected increases in the prevalence of clear-air turbulence do not necessarily imply more in-flight injuries or greater levels of passenger discomfort. Future improvements in clear-air turbulence forecasts, such as the Graphical Turbulence Guidance system, would improve the ability of pilots to divert around patches instead of unexpectedly encountering them.
Some modern aircraft are also fitted with an accelerometer in their nose cone. If the accelerometer registers a sudden change in altitude, which is large enough to be indicative of turbulence, the wing flaps are rapidly adjusted in an attempt to damp the vertical motion and reduce the acceleration. The risk could also be mitigated by equipping aircraft with Light Detection and Ranging (LIDAR) ultra-violet laser systems which can warn pilots of any invisible density perturbations indicative of clear-air turbulence up to 10-15 km ahead, potentially with enough time to alert passengers and crew, or possibly take an evasive manoeuvre. Although a 2002 study found a negative business case for installing such technology, Williams believes this could change as the technology becomes less expensive and clear-air turbulence becomes more prevalent.
In the meantime, he would like to extend the study to examining other seasons, flight levels and geographic regions.
“My top priority for the future is to investigate other flight routes around the world. We also need to investigate the altitude and seasonal dependence of the changes, and to analyse different climate models and warming scenarios to quantify the uncertainties,” he said.
Early last year, a study by Williams and a research team was published that looked at the impact on transatlantic flight times of a faster jet stream caused by climate change (see article).
Swedish project looks to narrow the emissions reporting gap between estimated and actual flight paths
Tue 11 Apr 2017 – Until now, calculating emissions from aircraft in Sweden has assumed airlines take the straightest and shortest routes, despite this not being the usual case in real-world conditions. A collaboration involving the Swedish Defence Research Agency (FOI), the Swedish Transport Agency and Sweden’s air navigation service provider LFV is now trying to narrow the gap between estimated and actual flight paths. The project has involved FOI, a leading defence and security research institute that also studies the environmental impact of aircraft, accessing LFV’s radar tracks from 2,200 domestic flights during a few weeks in 2016. By studying the radar tracks, FOI has been able to refine its calculation model and bring down the difference by around 8%. LFV said the outcome could lead to lower fuel consumption and a reduced climate impact from the aviation sector.
“Through including a fuel model in our radar analysis tool, we can help FOI and the Transport Agency to make more precise calculations of emissions from Swedish aircraft,” explained Patrik Bergviken, air traffic controller at Landvetter Airport and participant in the project.
“We will also be able to analyse how fuel consumption is affected by changes in airspace and working methods. It creates benefit and value for the airlines, which will also have more data to develop their operations and improve sustainability.”
State-owned LFV controls air traffic at 20 airports and from three control centres in Sweden. It says research and development is a key area of its focus, along with offering smart solutions through its international aviation consultancy arm.
FOI already maintains a confidential database of emission indices of NOx, HC and CO with corresponding fuel flows for turboprop engines that is used for compiling emissions inventories and emissions-related landing charges.
Although turboprop aircraft very seldom fly high enough to have an impact, another area of the FOI, LFV and the Swedish Transport Agency project is to study the high altitude effects of emissions from turbojet aircraft. FOI notes that reducing the environmental impact of aircraft often involves complex trade-offs between different environmental actions. The purpose of its work, it says, is to develop system analysis tools and methods with which to model the aircraft’s environmental impact so the total effect of changes and remedial measures can be assessed.
“We have access to tools for the calculation of emissions and are able to provide results that take account of how the aircraft is being operated, climatic effects and the existing laws and regulations governing environmental and climatic reporting,” said the institute, which also conducts noise studies and develops computational methods for sound generation and propagation from aircraft.