Nonstop Flying Is Safer Than Driving

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73935/1/j.1539-6924.1991.tb00584.x.pd

Validation of Proposed Go-Around Criteria Under Various Environmental Conditions

This paper evaluates the effects of environmental conditions on touchdown performance under varying approach states and validates proposed go-around criteria developed using data from a previously conducted study under these various environmental conditions. An experiment was conducted using Boeing 737-800 and Airbus A330-200 Level D full-flight simulators in which 24 pilots flew multiple approaches under different approach conditions and environmental variables. Pilots were instructed to always land the aircraft, even from conditions considered to be an unstable approach. Various touchdown performance metrics were analyzed. In addition, pilots perceptions of risk under the various unstable approach conditions and resulting landings were assessed. The results of the study revealed that wind speed/direction and visibility had a stronger effect on touchdown performance than the approach parameters. Specifically, wind had a highly significant effect on longitudinal and lateral touchdown point, as well as a significant effect on sink-rate at touchdown. Wind and visibility, along with localizer deviation, also had a strong effect on pilots perception of risk and workload ratings. Furthermore, the study confirmed that touchdown performance was similar among the runs with a 300-foot and 500-foot starting gate, as was found in the previously conducted experiment. These results support the previous finding that lowering the go-around decision gate to 300-foot might be acceptable, but suggest that certain environmental conditions might warrant altered thresholds of the proposed go-around criteria at this gate. Finally, the findings of this experiment highlight the importance of environmental factors in the assessment of risk of unwanted outcomes on approach and landing

Modeling Airline Frequency Competition for Airport Congestion Mitigation

Demand often exceeds capacity at congested airports. Airline frequency competition is partially responsible for the growing demand for airport resources. We propose a game-theoretic model for airline frequency competition under slot constraints. The model is solved to obtain a Nash equilibrium using a successive optimizations approach, wherein individual optimizations are performed using a dynamic programming-based technique. The model predictions are validated against actual frequency data, with the results indicating a close fit to reality. We use the model to evaluate different strategic slot allocation schemes from the perspectives of the airlines and the passengers. The most significant result of this research shows that a small reduction in the total number of allocated slots translates into a substantial reduction in flight and passenger delays and also a considerable improvement in airlines' profits

Aeronautical charging policy incentive schemes for airlines at European airports

This article was accepted for publication in the of Air Transport Management. The definitive published version is available at: http://dx.doi.org/10.1016/j.jairtraman.2013.06.009This paper introduces the concept of incentive schemes that may accompany airports’ aeronautical charging policies and develops a taxonomy of such schemes based on an analysis of data for 46 European Airports held in the RDC Aviation database.1 This taxonomy details the different types of incentive schemes that in are operation. It is clear their use is widespread and that the magnitude of the incentive is often significant. A financial benchmarking analysis is undertaken for four selected airports to illustrate the extent of the variations between airports both in terms of the basic characteristics of the incentive schemes and in the periods over which the discounts are available

Life cycle assessment (LCA) and life cycle costing (LCC) of road drainage systems for sustainability evaluation:Quantifying the contribution of different life cycle phases

Previous Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) studies on urban drainage systems only included construction materials in the system inventories. The present study aims to suggest an LCA and LCC method that for the first time, considers the inventories from four main phases in the life cycle impact assessment, including extraction of aggregates and production of construction blocks, transportation, construction, civil work and finally maintenance and end-of-life. LCA and LCC were carried out for 10 drainage systems including filter drains, infiltration trenches, soakaways, permeable pavement, infiltration basin, wetland, retention ponds, swales, filter strip, kerb and gully. Results showed that normalisation of environmental impacts and costs to drainage system size (length or area) was more appropriate for drainage systems with higher flow rate capacities (e.g., kerb and gully). However, drainage systems with low flow rate capacities that were designed to store runoff, required normalisation of environmental impacts and costs to storage capacity. The environmental impacts associated with urban drainage systems that needed considerable amounts of virgin aggregates (e.g., filter drains) were higher than those with limited construction material (e.g., swales). Transportation of materials and construction civil works had a larger contribution in life cycle inventories and associated environmental impacts in drainage systems with higher demand for materials. The lowest environmental impacts and life cycle costing were from swales, wetland and retention pond. Uncertainty assessment revealed that drainage systems with extensive application of materials and civil work had more negative impacts on human health, ecosystems and resources

Score a goal for climate: Assessing the carbon footprint of travel patterns of the English Premier League clubs

Football is the most popular sport, globally and in the United Kingdom. However it generates a range of negative environmental impacts, such as climate change, due to an extensive amount of travel involved. The growing contribution of football clubs to the global carbon footprint has been recognised, but never consistently assessed. This study assesses the carbon footprint of the English Premier League (EPL)clubs, using the patterns of their domestic travel in the 2016/2017 season as a proxy for analysis. The study shows that, within the 2016/17 season, the EPL clubs produced circa 1134 tonnes of CO 2- eq. as a result of their travel, where transportation accounts for 61% of the carbon footprint. To reduce this carbon footprint, a careful review of the current corporate travel and procurement practices in the EPL clubs is necessary. This is in order to optimise the travel itineraries, prioritise more climate-benign modes of transport and contract budget accommodation providers with the ‘green’ credentials