This study investigates the optimisation of design variables for the unconventional Flying-V-900 aircraft to minimise its climate impact, taking into account operational costs. The study
examines the compromises between operational costs and climate factors. A multidisciplinary
analysis and optimisation framework is developed in order to minimise the Flying-V-900’s
impact on global warming, cash operating costs, and fuel efficiency. This study investigates
the influence of geometry, turbofan engine, and mission design variables on these objectives.
The findings indicated that fuel- and cost-optimised designs demonstrated nearly identical
performance, whereas a climate-optimised design exhibited contradictory performance. These
results indicate that adopting a climate-optimised Flying-V-900 could potentially reduce the
impact of global warming compared to a conventional aircraft, as measured by the average
temperature response over a 100-year period, by approximately 60%. However, it is important
to note that this transition would come with a significant increase in cash operating costs,
specifically by 32%. This analysis considers the impacts of both CO2 and non-CO2 factors,
including contrail formation and NO𝑥 emissions. It demonstrates that the climate-optimised
Flying-V aircraft give priority to flying at a low altitude of 6km and a velocity of Mach 0.60 in
order to minimise contrail formation and NO𝑥 emissions. However, achieving this requires a
20% increase in fleet size to maintain productivity.

Aircraft redesign and flight path optimisation offer promising methods of rethinking how we fly. As the effects of aviation on the planet are becoming better understood, focus has shifted from cost minimisation to climate impact mitigation. In this study, simultaneous aircraft design and trajectory optimisation is used to investigate the trade-off between direct operating costs (DOC) and the global average temperature response (ATR) associated with a typical medium range flight. It is shown for a representative mid-latitude atmosphere and narrowbody aircraft that the ATR can be reduced by 49% with approximately 0.5% increase in operating costs through 2-dimensional flight path optimisation. With simultaneous wing planform optimisation, the DOC-ATR trade-off is even more favourable, leading to a 56% ATR reduction with no increase in operating costs. Results indicate that contrail avoidance is a highly cost-effective method of minimising the climate effects of aviation.

With the aviation sector growing each year, the need for a reduced climate impact is becoming increasingly important. Electrification of the propulsion system is believed to offer promising avenues in achieving this reduction. Additionally, airlines operating these aircraft have to adapt their operations and network to optimally utilize these aircraft. This research presents a methodology for the coupled design of a hybrid-electric aircraft fleet with strategic airline planning to optimally serve a specific network. The objective is to maximize the airline profit and minimize the network CO2 emissions. Aircraft design trade-offs in payload, range and runway length will guide the creation of new aircraft until the optimal aircraft fleet is determined. The methodology is tested in a case study for the regional airline network of SATA Air Acores. The study investigates the impact of introducing new hybrid-electric aircraft designs in the fleet on the creation of new aircraft, the aircraft allocation and the network performance. By directly integrating hybrid-electric aircraft design (having a parallel hybrid architecture) with strategic airline planning, it is possible to reduce the network CO2emissions by -11% at the cost of an airline profit decrease of -13%. When including a climate optimization, an additional reduction of network CO2 emissions is achieved of -27% with a small additional decrease in profit of -1%. Network profitability and climate impact are mainly dictated by the fleet diversity and the assumed technology level of the batteries employed in the aircraft. This research highlights the importance of including climate optimization in the design of new aircraft and the need for more advanced hybrid-electric propulsion architectures (such as distributed propulsion systems) to further contribute to climate impact reduction.

To reduce the climate impact of the turbofan dominated aviation industry, a conceptual propeller aircraft study has been performed to see the a possible reduction in climate impact between the two. The results analysed showed great promise for the reduction of the climate impact at the cost of block time. Additionally, a loss in productivity or fleet size is observed for the climate impact seen. The change in productivity or fleet size is remedied with an decrease in block time, however this results in an increase in climate impact, especially when compared to the turbofan aircraft. Overall it is safe to say that the climate impact can be reduced by utilising propeller aircraft, however either the productivity or fleet size must be changed. Additionally, the costs per flight potentially go up. All for a more sustainable and greener aviation industry.