8. Air cargo and passenger transport
The combustion process inside the jet engines is what determines most of the emissions produced from air transport. The magnitude and type of substances emitted are dependent on the level of thrust an engine has to produce for the different phases of a flight (taxi, take-off, climb, cruise approach and landing) which can be calculated when you know the type of aircraft the engine operates on.
The load factor is of great importance in all transport sectors; however, in aviation it is crucial to have a high load factor in order to be efficient. Added weight has a very large (non-linear) impact on the energy needed to perform a transport.
In the first release, the data base covers 82 various aircraft types and engine combinations relevant to the NTM members. The aircraft are specified in three different tables based on their use and configurations: pure cargo freighters (30), pure passenger airliners (38) and combined passenger and freight aircraft (14 belly freighters). Included metadata on all aircraft is maximum take-off weight, maximum payload capacity and the maximum range at maximum payload.
The NTM emission database builds on computations using the commercial software PIANO for certain fixed load factors (10), which in turn are used by the system developed at FOI (11).
The user inputs the distance and the weight of the payload to be transported. The system delivers relevant emission figures from the NTM database where the emission factors are divided into two groups:
- Constant Emission Factors (CEF) that corresponds to the high fuel usage during take-off and landing.
- Variable Emission Factor (VEF) that is multiplied with the flown distance.
The total emissions are calculated as the sum of VEF (multiplied with the flown distance) and CEF.
10) Simons, D. (1997) PIANO – Project Interactive Analysis and Optimisation – http://www.piano.aero/
11) Hasselrot, A. (2010): Data Preparation Manual for the Flight Emission Methods Hurdy-Gurdy and Hurdy-
Gurdy_GrinderXY, FOI-R-2972-SE – http://www.foi.se