Climb out 85%
Approach 30%
Taxi/ground idle 7%
The Boeing Aircraft Company conducted an extensive study for NASA on emission inventories for scheduled civil aircraft worldwide. The Boeing 2 Method is an empirical procedure developed for this study which computes in-flight aircraft emissions using, as a base, the measured fuel flow and the engine ICAO data sheets. Whereas the first Boeing method took into account ambient pressure, temperature and humidity, the second method was more complicated (and accurate). This new method allowed for ambient pressure, temperature and humidity as well as Mach number. The used methodology to calculate the emissions is reported in [23].
5.1.2 Effects of meteorological changes With the aim to show the effects of environment, Fig.11 describes how the pressure affects the Emission Index of NOX (EINOX) when the temperature is fixed. The figure shows that for high levels of pressure (during the takeoff or landing phases at ground level) EINOX is quite constant and it is not affected by temperature. On the contrary, for low level of pressure (during cruise level) low differences of temperature cause high difference of EINOX; in particular, they are inversely proportional across the range of 20- 50 kPa (troposphere).
Fig.11 Effect of pressure on emission index of NOx
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