Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
movements database.Emissions inventories for 1986, 1989, and 1992 were based on scheduled
air traffic only; a 4-D inventory with diurnal cycles for March 1992 was based on ABC data. ICAO
data (ICAO, 1997b) were used for emissions inventories for international (only) scheduled air
traffic in the years 1982 to 1992.
Calculation of fuel burned and emissions for aircraft differs between the three inventories. NASA
used detailedmanufacturers' proprietary performance information on each aircraft-engine
combination and the flight profile shown in Figure 9-6. Emissions were calculated from the
information in the ICAO Engine Exhaust Emissions Data Bank (ICAO, 1995), through the use of
Boeing "Method 2" procedures (Baughcum et al., 1996b, Appendix D), which allow extrapolation
of sea-level data in the ICAO data bank to the operating altitudes and temperatures encountered
throughout the aircraft flight profile.
The ANCAT/EC2 inventory used commercial software for flight and fuel profiling, along with
Project Interactive Analysis and Optimization (PIANO), a parametric aircraft design model. The
global civil fleet was modeled with a selection of 20 representative aircraft types. These
representative aircraft were assumed to be fitted with generic engines typical of the technology
and thrust requirements of each type. PIANO generated fuel profiles covering the entire flight
cycle, including steps in cruise for each aircraft. Fuel use during ground operations was
estimated from ICAO certification timings (ICAO, 1993).
The DLR inventory used airline data and an in-house flight and fuel profile model (Deidewig et
al., 1996). The DLR approach also used different aircraft/engine combinations from those utilized
by ANCAT. The aircraft mission was simulated by using a simplified flight modeling code as
point-to-point missions with no step cruise. Although the climb was calculated in iterative steps,
the cruise segment was treated as one section, applying the Breguet formula to calculate the
cruise fuel. Descent was assumed to be a gliding path with minimum engine load; no separate
approach procedure was used. A thermodynamic model for design and off-design operation of a
two-shaft fan engine was applied. Constant efficiencies and constant relative pressure losses for
main engine components were assumed for simplicity.
The ANCAT/EC2 and DLR inventories calculated NOx emissions from the fuel using the DLR
fuel flow method. This method has been tested and correlated with information from airlines,
flight measurements, and altitude chamber measurements (Deidewig et al., 1996; Schulte et al.,
1997).
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Figure 9-6: Scheduled aircraft mission profile.
Figure 9-7: Passenger traffic demand growth to 2015.
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