Air Traffic Management Concept Baseline Definition - The Boeing ...

Free Flight White Paper on System Capacity (Chew, 1997). The objective of the study
was the identification of a ‘critical’ year when the airline hub operating integrity threshold
is reached. The American Airline NAS study uses the 1996 Official Airline Guide (OAG)
as the starting point for analysis, representing over 18,000 flights per day.
100.00%
90.00%
Actual
Simulation - AA
Percent of Flights Within
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
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Delay in Minutes
24
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>33
Figure 2.5 American Airlines NAS Study Validated with Actual Delay Data
A simulation was conducted representing the jet traffic operating over 4,000 routes among
the 50 busiest U.S. airports. An annualized traffic growth of 2.3% was assumed, based on
a 4% growth in passenger enplanements. These values are consistent with FAA and
Boeing 1996 market outlook estimates. Current NAS separation standards were
estimated at 7 nm en route, 2 nm in the terminal area and between 1.9 and 4.5 nm for
wake vortex avoidance. Figure 2.5 indicates the model output compared with observed
American Airlines data on system delay. The comparison shows that the 1996 simulation
data agrees well with empirical results.
The analysis examines the change in the average delay system wide, with growth in traffic,
as well as the growth in the percentage of flights which experience more than 15 minutes
of delay in the system. The 15 minute delay figure is considered key to maintaining hub
integrity and provides a good indicator as to the hub viability. The simulation results in
Figure 2.6 indicate that the 15 minute delay statistic grows faster than the average delay
value. American’s study indicates delay problems in the NAS will become significant by
the 2005 to 2007 time frame.
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