Fuel burn rates of commercial passenger aircraft: variations by seat configuration and stage distance

Aircraft fuel consumption is a very large component of airline costs. Fuel burn is also very important because it is highly correlated with emissions and contributes directly to transport externalities. This paper calibrates fuel burn in kilos per seat per nautical mile for aircraft using the EMEP/EEA aircraft inventory database. We then employ the model with OAG flight schedule data to evaluate fuel burn by flight routes and aircraft types at a global scale. The paper shows comparative fuel use among different distance based markets as well as among a variety of routes in the long-haul market. The results show geographical heterogeneity of fuel burn rates among a variety of routes, while controlling for seat configuration and stage distance. The paper finds that stage lengths centered on 1500–2000 NM have the lowest fuel burn rates under current technology, fleet composition, and seat configuration. These findings, together with comments on the viability of long range flights provide better understandings not only for the carbon taxation debates but also for operational efficiency of current aviation markets. The lower rates for moderate distance flights seems to favor networks without extreme links, and supports the use of a hub connection scheme.     

Cost savings from trajectory deviations in the European air space

Air transport deregulation has lead to an increase of air traffic, together with a reduction of air fares. Air fare reduction has narrowed operational margins of airlines, bringing financial and employment instability. This has brought airlines to pay increasing attention to flying costs reduction. Two important components of flying costs airlines can try to cut modifying the planned flight are en route charges and operational costs. We rely on Demand Data Repository (DDR2) data to calculate deviations from planned flight trajectories to analyse the extent to what airlines try to cut operational costs making shorter flights than planned if possible, and cut en route charges providing a planned flight with lower en route charges than the planned flight. Our findings show that there is no generalised strategy among airlines to reduce en-route charges asking for deviations of the planned route. On the other hand, airlines are achieving savings of operational costs regularly. Higher savings per nautical mile are obtained in night flights, with longer planned distance and operated by low cost carriers.     

An analysis of the greenhouse gas emissions profile of airlines flying the Australian international market

International commercial flights (with the exception of flights between countries in European Union including Iceland, Norway and Liechtenstein) are currently not subject to greenhouse gas emission reduction regulation. To formulate effective and efficiency policy to manage greenhouse gas emissions from air transport, policy makers need to determine the emissions profiles of all airlines currently flying into their country or region. In this paper, we use 2012 data on airlines' aircraft characteristics, passenger load and cargo load (obtained from statistics reported by Australian Government Bureau of Infrastructure, Transport and Regional Economics) to estimate the volume and carbon efficiency on each international route flying to and from Australia. This is the first study to use actual passenger and cargo load data to determine the greenhouse gas (specifically CO₂) efficiency of airlines operating in the Australian international aviation market. Airlines' CO₂ emission profile is dependent on many factors including but not limited to the aircraft used, payload, route taken, weather conditions. Our results reveal that the airlines’ CO₂ emission profile is not only dependent on the aircraft used and the number of passengers but also the amount of cargo on each flight.     

Analysis of the recent evolution of commercial air traffic CO2 emissions and fleet utilization in the six largest national markets of the European Union

This paper presents the results of a study performed to analyze the evolution of commercial air traffic and CO₂ emissions in the European Union, from 2010 to 2013. Data sources are the European Commission's Eurostat Air Transport Statistics (Eurostat) and EUROCONTROL flight plans database. The changes in the fuel efficiency are analyzed and the potential reasons for those changes investigated. The evolution in the airline fleet composition during the last decade is presented as one of the reasons for the improvement in fuel efficiency, measured in burnt fuel per total Revenue Tonne Kilometre (RTK), as well as the different parameters depending on the airline business model (network carriers, low cost companies, etc.) and the aircraft type.Results show a slight reduction in the traffic, both for passengers and cargo (about −0.8%), and a more important reduction in CO₂ emissions (−4.3%), thanks to an improvement in the fuel efficiency parameter (−3.5%) for the three years period. There has been a relevant change in the fleet composition in the last ten years, with the replacement of older models for more efficient ones, and a shift to larger aircraft, particularly in the regional segment. Traffic has decreased in shorter distances (internal EU traffic), but increased in more efficient long range flights (extra-EU traffic), resulting also in an improvement of the efficiency parameter as average aircraft size and stage length increases.     

Investigations on the distribution of air transport traffic and CO2 emissions within the European Union

This study analyses the structure of air traffic and its distribution among the different countries in the European Union, as well as traffic with an origin or destination in non-EU countries. Data sources are Eurostat statistics and actual flight information from EUROCONTROL. Relevant variables such as the number of flights, passengers or cargo tonnes and production indicators (RPKs) are used together with fuel consumption and CO₂ emissions data. The segmentation of air traffic in terms of distance permits an assessment of air transport competition with surface transport modes.The results show a clear concentration of traffic in the five larger countries (France, Germany, Italy, Spain and UK), in terms of RPKs. In terms of distance the segment between 500 and 1000 km in the EU, has more flights, passengers, RTKs and CO₂ emissions than larger distances. On the environmental side, the distribution of CO₂ emissions within the EU Member States is presented, together with fuel efficiency parameters. In general, a direct relationship between RPKs and CO₂ emissions is observed for all countries and all distance bands. Consideration is given to the uptake of alternative fuels. Segmenting CO₂ emissions per distance band and aircraft type reveals which flights contribute the most the overall EU CO₂ emissions. Finally, projections for future CO₂ emissions are estimated, according to three different air traffic growth and biofuel introduction scenarios.     

Airline fuel usage and carbon emissions: Determining factors

Using annual data on individual US airlines over the 1995–2015 period, this paper presents regression results relating an airline's total fuel usage to seven variables: the available ton miles of capacity (passengers plus freight and mail) provided by the airline; the average seat capacity of its aircraft, average stage length (flight distance); average load factor (measured by weight); the average vintage (construction year) of its aircraft; the percentage of the airline's flights that are delayed; and the average annual fuel price. The results show how fuel usage and carbon emissions depend on a small set of crucial variables. The estimated fuel-price effect allows the emissions impact of an optimal emissions charge to be computed, and the estimated delay effect shows the emissions impact of an industry-wide reduction in flight delays. The regression model is generated from a theoretical framework.     

Impacts of COVID-19 on aircraft usage and fuel consumption: A case study on four Chinese international airports

COVID-19 pandemic starting in early 2020 has greatly impacted human and industrial activities. Air transport in China shrank abruptly in February 2020, following a year-long gradual recovery. The airline companies reacted to this unprecedented event by dramatically reducing the flight volume and rearranging the aircraft types. As the first major economy that successfully controls the spread of COVID-19, China can provide a unique opportunity to quantify the medium-long impacts on the air transport industry. To quantify the corresponding changes and to elucidate the effects of COVID-19 in the wake of two major outbreaks centered in Wuhan and Beijing, we analyze twelve flight routes formed by four selected airports, using the Automatic Dependent Surveillance-Broadcast (ADS-B) data in 2019 and 2020. Our results show that the total flight volume in 2020 reduced to 67.8% of 2019 in China. The recovering time of flight volume was about 2–6 months, dependent on the severity. In order to unwind the severe challenge, airlines mainly relied on aircraft B738 and A321 between February and June in 2020 because the fuel consumption per seat of these two aircraft types is the lowest. Besides, fuel consumption and aircraft emissions are calculated according to the Base of Aircraft Data (BADA) and the International Civil Aviation Organization's Engine Emissions Databank (ICAO's EEDB). At the end of 2020, the ratios of daily fuel consumption and aircraft emissions of 2020 to 2019 rebounded to about 0.875, suggesting the domestic commercial flights were nearly fully recovered. Our results may provide practical guidance and meaningful expectation for commercial aircraft management for other countries.     

Risk analysis of the EASA minimum fuel requirements considering the ACARE-defined safety target

We present the results of flight simulator experiments (60 runs) with randomly selected airline pilots under realistic operational conditions and discuss them in light of current fuel regulations and potential fuel starvation. The experiments were conducted to assess flight crew performance in handling complex technical malfunctions including decision-making in fourth-generation jet aircraft. Our analysis shows that the current fuel requirements of the European Aviation Safety Agency (EASA) are not sufficient to guarantee the safety target of the Advisory Council for Aviation Research and Innovation in Europe (ACARE), which is less than one accident in 10 million flights. To comply with this safety target, we recommend increasing the Final Reserve Fuel from 30 min to 45 min for jet aircraft. The minimum dispatched fuel upon landing should be at least 1 h.     

The cost of abatement options to reduce carbon emissions from Australian international flights

In 2012, a total of 13.1 million tonnes of carbon dioxide were emitted by 14 airlines while transporting 72 per cent of international passengers into and out of Australia in 2012. With passenger and cargo traffic growing at between five to six per cent annually from 2013 to 2033, acquiring more fuel efficient aircraft to both renew the existing fleet and to service growth has the greatest potential in reducing emissions over the next 20 years. Our analysis shows that implementing carbon dioxide emissions abatement options such as installing light weight seats, iPad electronic flight bags, winglets, washing aircraft engines and reducing the number of engines used during taxiing, all offer net financial savings when considered over 20 years. Acquiring new fuel efficient aircraft has the biggest impact on emissions reduction. Low interest loans and longer loan repayment periods may incentivise airlines to acquire more fuel efficient aircraft to service traffic growth but other complimentary incentives and penalties are required to influence airlines to replace their current fleet with more fuel efficient aircraft.     

Drivers of airline loyalty: Evidence from the business travelers in China

This paper examines the key factors that determine business traveler loyalty toward full-service airlines in China. Based on literature review and panel interview, ten airline attributes under three categories were derived: (a) operational factors: safety, punctuality, and aircraft; (b) competitive factors: frequency of flights, schedule, frequent flyer program, ticket price, and reputation; and (c) attractive factors: in flight food & drinks and in flight staff service. We surveyed 2000 Chinese business travelers on domestic flights, obtaining 462 usable questionnaires. Hierarchical regression analysis reveals that reputation, in-flight service, frequent flyer program, and aircraft have the greatest influence in driving airline loyalty.     

The benefits of tankering considering cost index flying and optional refuelling stops

This work presents the application of a fuel tankering strategy to an airline considering cost index flying and the possibility of using intermediate optional refuelling stops. The tankering solution was based on integer linear programming algorithm using a network modelling strategy. Two methodologies have been used to calculate mission performance according to the aircraft cost index, the first is the complete method where every flight phase (climb, cruise and descent) are optimized according to the cost index. This methodology has the disadvantage of being a slow process as the optimization of every flight leg is time consuming. The second approach is a simplified method, which is based on the Breguet equation and has the advantage of being a quick solution for an initial tankering assessment analysis. A comparison is made between these two methodologies on a simulated multi-stage flight mission demonstrating the validity of this simplified approach. The benefits of a tankering flight using cost index and refuelling stops are illustrated by a study case of a network linking six airports and seventeen optional refuelling stops with different fuel costs. The results from the optimized flight route show a 3% cost reduction at the specific multi stage mission example when compared to a more traditional dispatch approach without the use of the fuel tankering strategy.     

Air freight hubs in the FedEx system: Analysis of fuel use

This paper provides a data based analysis of FedEx air freighter activities from selected hub locations. The basic idea is that air freighters have a set of range and payload parameters and their corresponding fuel burn depends on weight and distance. Data from 2011 to 12 (FlightAware) are used for 180,000 + flights on origin, destination and aircraft type. The particular aircraft vary widely in payload, but additional parameters may be derived from industry web sites and BTS. The research uses flight activity at hubs such as Memphis and Indianapolis (among others) and computes the aggregate distance flown on specific aircraft. The linkage between the hub and aggregate fuel use (assuming that the out bound flights are allocated to the hub) will give some quantifiable measures of the costs allocated to the hub. The paper examines particular aspects of the air freight system that are especially vulnerable to a spike in the costs of aviation fuel. These observations suggest that traffic to regional air express and air freight hubs is likely to respond in complex ways to fuel costs.     

Emissions,performance, and design of UK passenger vehicles

Consumer, legal, and technological factors influence the design, performance, and emissions of light-duty vehicles (LDVs). This work examines how design choices made by manufacturers for the UK market result in emissions and performance of vehicles throughout the past decade (2001–2011). LDV fuel consumption, CO₂ emissions, and performance are compared across different combinations of air and fuel delivery system using vehicle performance metrics of power density and time to accelerate from rest to 100 km/h (62 mph, t_z-62). Increased adoption of direct injection and turbocharging technologies helped reduce spark ignition (SI, gasoline vehicles) and compression ignition (CI, diesel vehicles) fuel consumption by 22% and 19%, respectively, over the decade. These improvements were largely achieved by increasing compression ratios in SI vehicles (3.6%), turbocharging CI vehicles, and engine downsizing by 5.7–6.5% across all technologies. Simultaneously, vehicle performance improved, through increased engine power density resulting in greater acceleration. Across the decade, t_z-62 fell 9.4% and engine power density increased 17% for SI vehicles. For CI vehicles, t_z-62 fell 18% while engine power density rose 28%. Greater fuel consumption reductions could have been achieved if vehicle acceleration was maintained at 2001 levels, applying drive train improvements to improved fuel economy and reduced CO₂ emissions. Fuel consumption and CO₂ emissions declined at faster rates once the European emissions standards were introduced with SI CO₂ emissions improving by 3.4 g/km/year for 2001–2007 to 7.8 g/km/year thereafter. Similarly, CI LDVs declined by 2.0 g/km/year for 2001–2007 and 6.1 g/km/year after.     

CO2 emissions associated with hubbing activities in air transport: an international comparison

Hubbing is an important operational practice in air transport. Many studies have been conducted to examine the benefits and impacts of hubbing from an economic perspective. However, its impact on CO₂ emissions, especially across different air spaces, is not well understood. This paper explores the impact of hubbing activities in air transport from an environmental perspective. With a detailed methodology and data from the Greek and Hong Kong/Sanya flight information regions (FIRs), three levels of CO₂ emissions are estimated: airport-based, airspace-based and flight-based. After contrasting the CO₂ emission efficiencies of Athens International Airport (AIA) and the Hong Kong International Airport (HKIA), aircraft type and flight distance are examined to explain their emission efficiency differences. It is found that HKIA is associated with poorer CO₂ emission efficiency at the airport and airspace levels because of the larger aircraft and longer flight distance. However, when CO₂ emission efficiency at the flight level is considered, HKIA, with a higher passenger load factor, performs better. Major international hub airports should implement additional environmental measures to minimize the impact of hubbing activities on CO₂ emissions at the airport and airspace levels.     

The potential for European aviation CO2 emissions reduction through the use of larger jet aircraft

There is increasing pressure to reduce global CO₂ emissions, with aviation targeted as an industry with high future expected growth and limited potential for reduced emissions. In Europe, air transport is likely to be included in the Emissions Trading Scheme from 2012, allowing open trading with other sectors. The proposed scheme may be economically efficient but will it do much towards curbing aviation emissions? A number of papers have looked at the ETS impact on air traffic growth rates, and others have forecast the rate of likely future fuel efficiency gains. This paper examines the potential for greater fuel efficiency through the use of larger aircraft and different patterns of operation. Fuel efficiency was found to be related to aircraft size with more benefit from trading up with short/medium-haul than with long-haul aircraft. This relationship only held for long-haul aircraft if those aircraft with two main decks were removed from the sample (these types showing inherently lower fuel efficiency). Combining these findings with manufacturers' and other forecasts of average aircraft size suggests that less than 1% a year of fuel efficiency gains will be available from this source over the next 20 years.     

Identifying flight fatigue factors: An econometric modeling approach

The paper looks at responses of crewmembers of six Taiwan air carriers who were asked to report their levels of fatigue before takeoff and after landing. Ordinal probit models are employed to estimate three fatigue models for different flight operations and serve as vehicles to investigate flight fatigue factors and identify their relative significance. The top three factors for long haul flights are found to be sleep quality at home, sleep quality on aircraft and “nod-off “experiences; for regional flights, age, extra non-flying tasks on the ground, and experiences of fatigue during flight operations are important; and for domestic flights poor cockpit environment, age, and experiences of fatigue during flight operations are relevant.     

Complaints caused by aircraft operations: an assessment of annoyance by noise level and time of day

The impact of aircraft movements on the local community surrounding an international airport was investigated using airport data on complaints, noise monitoring, aircraft flight paths and movements to assess annoyance due to noise level and time-of-day. As predicted, the louder the noise the more complaints were generated, with twice the complaints per movement at 110–114 PNdB compared with 74–79 PNdB.The hourly patterns in flight frequency and complaints were clearly distinct. Calculations of the complaints per aircraft movement for each hour of the day showed a striking 24 h pattern with night flights (23.00–06.00) causing on average nearly five times more complaints than the rest of the day (06.00–23.00). The time of the greatest propensity to complain about aircraft noise was between 01.00 and 02.00 and the lowest between 08.00 and 09.00.The circadian pattern in sensitivity to aircraft noise could be used to inform the development of airport operations and flight movements to minimize community disturbance.     

How do carriers price connecting flights? Evidence from intercontinental flights from Europe

In civil aviation, hub-and-spoke (HS) networks are used by all large carriers. The importance of this system implies that many travelers use connecting flights. Nevertheless, only scarce knowledge is available on price formation of these trips. In this paper, we focus on the fares of connecting intercontinental flights, with one stop and at least one competing direct flight. We develop a simple model of a HS network, with imperfect substitutability between direct and indirect flights and Cournot competition on every route in the network. We test the model empirically, using reported fares for flights from seven European origins, including the five major airports in Europe, to five non-European destinations. We find that the fare of a connecting flight can be expressed as the weighted average of the fare of its direct competitor, the travel times of both flights its costs and the monetary value of the utility attached to the trip. The weight of the direct fare decreases as product diversity increases.     

A global model for estimating the block time of commercial passenger aircraft

This paper uses a two-stage statistical model to estimate the block time of commercial passenger aircraft. The model considers many of the factors contributing to airport congestion and provides a basis for future development of multivariate statistical models of the flight operation process. The model is tested using 2 million US domestic flights by six airlines in 2004. Model analysis provided insight regarding the relative impact of weather conditions and airport utilization on block time. In particular, population, arrival time, airport utilization, ice, and the interaction of poor weather conditions and traffic were found to be significant predictors of block time.     

Critical aggressive acceleration values and models for fuel consumption when starting and driving a passenger car running on LPG

The models based on vehicle speed have been used to estimate fuel consumption and CO₂ emissions. However, these models could not properly estimate the change in fuel consumption and CO₂ emissions as the speed changes. As for the alternative method, people try to consider using acceleration instead of speed. Although acceleration has been seriously considered, determining critical aggressive acceleration value in relation to fuel consumption and CO₂ emissions is difficult to find. In this study, evaluation models of fuel consumption were developed using instantaneous acceleration, and we defined the critical aggressive acceleration values for different states of the vehicle from the viewpoints of fuel consumption and emissions. We used a mid-sized Liquefied Petroleum Gas (LPG) passenger car and obtained instantaneous data from a digital tachograph installed in the car while it accelerates. We developed two fuel consumption models and found critical aggressive accelerations, respectively: a model of starting vehicle that measures range of speed required to overcome the inertia during acceleration from stop state, and the other model for the driving state. We used Classification and Regression Tree (CART) analysis to find the critical aggressive accelerations at which the increments of fuel consumption change abruptly. As a result, the critical aggressive accelerations causing abrupt change in the increments of fuel consumption were found to be 2.598 m/s² for the starting of vehicles and 1.4705 m/s² when driving them. We also found that the increments of fuel consumption can be explained through quadratic and exponential functions with instantaneous acceleration.