Optimisation of the Aircraft Cost Index for Air Travel Emissions Reduction

The aviation industry is facing a tough challenge to achieve carbon neutral growth from 2020. The industry’s emissions continue to grow at a substantial rate, spurred by a 5% per annum increase in demand and a lack of large scale solutions to reduce its dependence on oil.
A promising mitigation measure is the use of the Cost Index (CI) tool, its purpose being to balance the cost of time and the cost of fuel. The faster the flight, the more fuel is used and therefore costs increase. However, slower flights increase time-dependent costs, such as crew and maintenance costs. The CI value is entered into the aircraft flight management system to determine the speed of the flight.
Analysis from this thesis reveals that CI could result in emissions savings of at least 1% on a flight-by-flight basis, comparable with other measures that can be implemented in the short-term. However, evidence suggests that airlines are currently misusing or miscalculating their CI values, resulting in higher costs and emissions.
The aim of this thesis is to develop a novel method of calculating CI to make it practical and easy to use for airlines on a day-to-day basis. This was done by undertaking multiple CI calculations for different flight parameters and finding the CI value which minimises costs. This takes into account time-dependent costs, fuel costs and any carbon pricing to be applied, as well as any costs relating to passenger delay.
The model also has a dual purpose of helping in the understanding of future impacts on an individual flight basis. It is found that in general the CI follows trends in jet fuel costs. However, when delay is added this has the most significant impact on the CI. Conversely, the addition of a carbon price, which is a key policy strategy in the industry to reduce emissions, had a negligible effect on the CI and resulting emissions. Future policy will need to recognise that these flight-by-flight interactions are important in order to find solutions that lead to meaningful CO2 reductions in the industry.