Search

This thesis investigates the concept of fuel-reduction via formation flight of long-haul commercial aircraft on a network-wide scale, particularly addressing the issue of combinatorial complexity in global formation routing and allocation. A multi-stage formation flight planning (MS-FFLIP) tool is proposed as a computationally tractable approach to formation allocation. Assuming all trailing aircraft receive a 10% reduction in the fuel-burn by flying in formation, the optimal routes including the joining and splitting points are computed in four specific stages along the flight depending on the desired formation size. Within a stage, the interconnected allocation problem takes a set of flights, their possible formation combinations and associated costs and optimally assigns them in a fuel-cost minimising formation fleet. The formation flight routing and the associated fuel burn are enumerated rapidly. This fast computation allows the large-scale allocation problem to be solved via a Mixed Integer Linear Program and optimised through an external optimiser solver. Within the context of this thesis, a stage is defined as a collection of events where all flights merge into formation at optimal joining points, driven by an event-based simulation. The MS-FFLIP tool sequentially creates stages until the largest allowable formation size is created. Additionally, the model is capable of handling large sets of flights and in creating large formations of up to sixteen-aircraft allocated to a formation within a real-time operational time limit. Similar models exist in the current literature, however they are highly prone to combinatorial complexity and as a result, their computation times diverge dramatically with increase in aircraft number and formation size. For this reason, the models were not able to capture the majority of the potential fuel-savings. The MS-FFLIP model was compared against the conventional single-stage centralised formation flight planning approach for wh, Aerospace Engineering, Air Transport and Operations