Precision of calculations
How precise are the calculations?
For the purpose of emissions calculators, emissions are calculated on the basis of average values (detailed calculations can be downloaded here). Fuel consumption, for example, for short-haul flights (<1,000 nautical miles) is calculated on the basis of the three most commonly used aircraft in the EU, weighted using EU passenger data. Average values are also used for number of seats and load-factor (percentage of seats taken). The BOKU system applies a factor of 1.09 to account for detours, weather conditions, holding patterns etc.
Individual flights will of course use more and less efficient aircraft. The plane may be full or fairly empty, and weather conditions or air traffic may lead to considerable detours.
All of these values have an influence on the per-passenger emissions calculated. For this reason, it is possible that the emissions of a specific flight vary considerably from the value calculated (on the basis of the average values). Over the course of a large number of calculations however, due to the fact that they are based on average values the calculations will be fairly accurate.