8.2 Air methods
In this paper NTM presents environmental data and calculation methods for 82 different commercial aircrafts. When calculating aircraft emissions care needs to be taken in choosing the right aircraft or type of aircrafts since environmental performance varies both with aircraft/engine configuration and the type of aircraft (freight, belly freight or passenger). Calculations on for example belly freight, taking into consideration that more of the aircraft’s volume and weight is used for the passengers, show approximately 30% lower emissions for belly freight (Blinge M., 2003) as compared to pure freighters.
It should be stressed that the method of allocation of the emission data between passengers and freight strongly influences the results. There are several issues regarding the methods to be resolved, e.g. which parameter (revenue, weight, volume etc.) should be selected as a base for the calculation. NTM will continue to monitor the development of possible standards in this area and present the result in coming works. In the autumn of 2007 a study on allocation within ferries were presented by NTM that will initiate further progress in this field.