A.- EXAMEN ESTOMATOLOGICO EXTRA ORAL:
V. DISCUSIÓN
There are three possible reactions to night flight restrictions at airports:
• Relocating flight movements
• Rescheduling flight movements
• Cancelling flight movements
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Relocating flight movements to other airports requires an adequate infrastructure, compatibility to the local night flight regulation, free slot capacity and an acceptable landside connection to the final transport destination. There are a couple of consequences of relocations for the airports, the airlines, regional and local actors, passengers and cargo-runtime. In respect to the impacts of airlines there is a difference between home and non home base carriers.
Carriers that have to relocate flight movements away from their home base cannot use their own service infrastructure any more. As a consequence, they also have to relocate maintenance capacity to the new airport. Moreover the crew has to stay at a hotel instead of their home base and on the next day the daily rotation has to start with a ferry flight to the main origin. All this generates additional costs.
Non home base carriers generally could relocate flights because they are not bound to the airport. They easily could make new maintenance contracts without many additional costs. In case of a night flight restriction at a hub airport night flights might be cancelled instead of relocated, because flights that are bundled in a hub and spoke system are obsolete, if they don’t reach the hub. In general, it is not economical to relocate transfer passengers or transfer belly freight to other airports.
Rescheduling flight movements from the core night time to early or late daytime is another possibility to avoid night flight movements. But initially the feasibility of rescheduling depends on the availability of corresponding slots at the origin and destination airports.
Rescheduling, however, is not feasible for all segments of air transport. Especially line operating passenger airlines, integrators and night airmail operators are integrated in hub and spoke networks. Rescheduling a single flight, which is integrated in a balanced and optimized network, means that passengers or cargo might miss the best connection. Therefore the overall transportation time would increase. In consequence particularly premium passengers and senders of time-sensitive cargo goods would decide for alternative airlines/airports. If, consequently the capacity load factor declines, the price per passenger / per tonne needs to be increased to make the flight profitable for the airline. Considering the competition in the air transport market, the airlines cannot overprice without running the risk of loosing passengers or cargo. If the revenue on flight operations declines the break-even point, the cancellation of this service might become necessary.
7 Conclusions
With ongoing air traffic growth and subsequent airport extensions, night flight restrictions, which aim at reducing noise impacts of airports, are getting more popular. In this context, forecasting night flight movements, evaluating the external
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costs of night flights and assessing the importance of night flights for airlines emerge as research fields.
In general, no best practice exists to forecast the future demand of night flight movements. Thus we developed a straightforward methodology to forecast night flights at a specific airport presented in this paper. It builds on a detailed analysis of past and current patterns of night activities of relevant air traffic segments, assumptions regarding the future importance of night movements and a general air traffic forecast. A limitation of this approach is that the patterns of night movements at an airport are usually already influenced by existing restrictions. This has to be considered if such patterns are projected onto the future.
The analysis reveals that different air traffic segments require more night flight movements than others. Reasons for night flights are diverse, ranging from competition driven extension of aircraft operation hours to the demand driven operations at night for cargo and intercontinental passenger traffic. In this context, it is difficult to judge, which night flights are “essential”; certainly different perceptions arise. Every scheduled flight that generates revenue might be essential for airlines.
People living close to the airport will certainly judge in a different way. In addition, there are several constraints on rescheduling night flights or relocating them to other airports.
In order to acquire an unbiased basis for the regulation of night flights, both the external costs and the economic significance for airlines of night flight movements need to be studied in more detail. Furthermore, possible relocation / rescheduling strategies need to be assessed. To cater for competition issues, it might even be necessary to tackle the issue of night flight regulation not only in the context of plan-approval procedures for specific airports but also on a national or even global level.
List of figures
Fig. 1: Survey of night flight restrictions in Europe ... 44
Fig. 2: Methodological framework... 45
Fig. 3: Distribution of night flight movements per week ... 47
Fig. 4: Segmentation of air traffic at Frankfurt Airport ... 49
Fig. 5: Diurnal distribution of takeoffs and landings for different air traffic segments... 50
Fig. 6: Overview of the development paths ... 53
References
This paper is based on consulting work of our Institute in the context of the airport extensions of Frankfurt and Munich airports. The related reports are unpublished and therefore, no references are given.
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Chrsitian Blank
is an urban and transport planner and researcher at Institute for Transport Planning and Logistics, Hamburg University of Technology (TUHH) D-21071 Hamburg, Germany E-mail: [email protected]
Dr. Tina Wagner
is a transport planner and civil engineer at Hamburg Ministry of Urban Development and Environment Infrastructure Development Directorate