Air Transportation is a
Complex Adaptive System
not an Aircraft Design:
Innovation at the Interface of Disciplines
Dr. George L. Donohue
Department of Systems Engineering and Operations
Research
George Mason University
Problem
• > 11 % of US Disposable Personal Income goes to
Transportation
• Highways and Airways are Approaching Gridlock and
Hub lock
• Traditional Engineering Approaches are Failing to
Find Solutions
• New and Innovative Systems Approach is required to
overcome Traditional Stovepipe solution shortfalls and
Political/Economic Barriers
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The Aviation Capacity and Safety
Challenge
Air Traffic Could Triple in Next 20 Years
“The current air traffic management system is near its capacity
limits with extensive system delays and inefficiencies resulting in
annual losses to users estimated at over $3.5B.”
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National Airspace System
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Hub and Spoke
Network
Completely Connected Network = 2(N-1) Flights
(eg., 50 Airports, 98 Flights)
Ref: J. Hansman, MIT
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Hub Airports
Becoming Saturated
ASYMPTOTIC BEHAVIOR OF AIRPORTS
at 4 N.M. Arrival Separation (32 Arrivals/Rw/Hr)
120%
100%
80%
60%
San Fransisco
John Wayne
Las Vegas
40%
Mineapolis
Newark
LaGuardia
20%
0%
1988
1990
1992
1994
1996
1998
YEAR
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Air Transportation System
at 58% Max Capacity
HUB & SPOKE OPS GROWTH at 57 US MAJOR AIRPORTS
60
A/C OPS/YR
CAP LIM @ 7 Km
50
50% MAX CAP
5 Km sep
40
30
20
10
0
1985
1990
1995
2000
2005
2010
2015
YEAR
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ATS Delays will Grow
Exponentially
NUMBER DELAYS
( >15 min / 1000 operations)
PREDICTED DELAY vs. CAPACITY FRACTION
50.0
45.0
40.0
35.0
30.0
25.0
20.0
15.0
10.0
5.0
0.0
0%
20%
40%
60%
80%
100%
AIRPORT CAPACITY FRACTION
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1900
10 %
1910
VDL, ACR
GPS
Jet Transports
First VORs
DC-3
Assembly Line
Model T
Relative
Market
Growth
GAP Engines
Inter City Transportation:
Time for a Paradigm Shift ?
90%
10%
90%
Small
Aircraft
Transportation
System?
Jetliners Displace Props
90%
10%
Propliners Displace Cars
90%
10%
Cars Displace Trains
1920
1930
1940
1950
1960
1970
1980
1990
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2010
2020
2030
9
Vision of the Future for InterModal Transportation
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Fully Connected
Network
Completely Connected Network = N(N-1)
(eg., 50 Airports, 2450 Flights)
Ref: J. Hansman, MIT
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National Air
Transportation Network
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ATM System Functional
Structure (Boeing Model)
Schedule of
Capacities
Weather
National
Flow
Planning
Flight
Planning
Flight Schedule
Airline
Desired
Sector
Loads
Facility
Flow
Planning
Execution
Sector
Traffic
Planning
Planning
CFMU
Efficiency
Clearance
Requests
Clearance
Requests
Sector
Traffic
Control
Safety
TMU
D-Side
Throughput
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R-Side
AC State
Sensor
Aircraft
Guidance and
Navigation
Traffic
Sensor
Pilot
Other AC
13
Future Air Traffic Broadband
Network Requirements
AIRBORNE WEATHER OBSERVATION
VOICE
OPERATIONS, MAINTENANCE
MESSAGING
AIRCRAFT
NEGOTIATION
ADS-B
AIRCRAFT
POSITION/
INTENT
AUTOMET
FIS TIS APAXS
•WEATHER
•NAS
STATUS
CPC
ADS-B
CPDLC
DSSDL
NATIONAL
WEATHER
SERVICE
•TV, RADIO
•INTERNET
AOC
COMM
Commercial
Service Provider
NWIS
OTHER
AUTHORIZED
USERS
AIR
TRAFFIC
CONTROL
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•INTERNATIONAL
•MILITARY
•FBO’S
AIRLINES
OPERATIONS
CENTER
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Next-Generation Data link
Communications
GEO
GEO
LEO/MEO Systems
Military
Regional/
Commuters
General
Aviation
Gateway
Line-ofSite
Ground
Networks
Commercial
Transport
Corporate
Ground
Earth
Station
Rotorcraft
Commercial
Service Providers
Terminal Area
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System Integration
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Auto Flight Issues
• Large Number of Aircraft will require High degree of
GA Flight Deck Automation to Increase Safety
• Control and Communication aspects of Distributed
Multi Aircraft environments, evaluation of control
laws as a function of Airspace Dynamic Density
• Cooperating Auto Pilots and Collision Avoidance
Systems will stress Wireless Communications
Bandwidth
–
Loads and Protocols need to be evaluated
• Human - Computer Interaction requires a Cognitive
Workload Experimental Evaluation
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• BACKUP MATERIAL
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Telcom System Issues
Utilization
Avionics Issues
•Equipage / Avionics Cost
•Applicability Across Platforms
•Mandatory/Primary/Optional
Service Provider •Architecture - OSA / Proprietary
•FAA
•Level of Integration
Link Characteristics
•Other Government
•Spectrum / Frequency
•Public / Private Commercial
•Bandwidth
Delivery
•Modulation
Quality-of-Service
•Voice/Data
•Timeliness/Latency
•Simplex/Duplex •Access Technique
•Priority
•Broadcast
Coverage
•Availability
Phase-of-Flight •Line-of-sight
•Redundancy
•Over-the-Horizon •Global
•Planning
•Regional
•Robustness
•Surface Movement
•Oceanic
•Terminal Operations
•Line-of-Sight
•En Route / Oceanic
•Civil Transport
•General Aviation
•Military
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Perceived Barriers to
Paradigm Shift
•
•
•
•
•
There is not enough Airspace
Aircraft are Too Hard to Fly
Aircraft are Too Expensive
Flying is Not Safe
Airports are Too Noisy
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Airspace & Airports
• Free Flight Paradigm should allow more
aircraft in the enroute airspace
– ( > X 20 ? )
• > 5,000 Airports in US within 30 minutes of
population – Direct Flight Opportunities
• However: SATS Operations will Grow like
N(N-1) vs. 2(N-1) for Hub and Spoke
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Aircraft Human Factors
• Large commercial aircraft now have:
–
–
–
–
3 axis auto-pilots & auto-landing modes
3 D GPS
Moving Map Displays
Terrain and Aircraft Collision Avoidance
• Non-Recurring costs have been Amortized
• Recurring costs for new GA should be small
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Air Transportation
Activity - ETMS Data
US IFR & FLIGHT FOLLOWING AIR TRAFFIC ACTIVITY
NUMBER OF AIRCRAFT ALOFT
6000
5000
4000
3000
TH 4/15/99
FR 4/16/99
SA 4/17/99
SU 4/18/99
2000
MO 4/19/99
EST 5433 PEAK
7:30
23:30
1000
0
0
5
10
15
20
25
30
TIME OF DAY (HOUR,EST)
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A/P Growth Req’d to Avoid Hub
Delay Increase (DPAT model)
No major changes to airline schedules, fleet mix, operations
Traffic growth = 2.3% per year
Clear weather conditions
2025
2020
2015
2010
2005
2000
1998
100
(minutes per aircraft)
Average Arrival/Departure Delays
120
80
60
Hold
Hold delays
delays to
to today’s
today’s levels
levels
40
20
0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Increase in Airport Arrival/Departure Rates
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