Looking for the Capacity in NGATS
George L. Donohue, John Shortle and B. Jeddi
Systems Engineering and Operations Research
Center for Air Transportation Systems Research
Volgenau School of Information Technology and Engineering
NextGen Research on Aviation Capacity
TRB January 2008
CENTER FOR AIR TRANSPORTATION SYSTEMS RESEARCH
© CATSR 2008
Outline
• What has Changed in 50 Years?
• Safety is the Underlying Capacity Constraint
• Current Safety Trends
• Airport Arrival – Departure 90% CEP
• What are the Underlying Causes of Delay?
• Too Many Scheduled Flights into Too Few Runways
– Average Aircraft Gauge Too Small
– Stochastic Queuing Delays Too Inefficient
– 80-90% Max Capacity Safety and Economic Optimum
• What Does NGATS do for Safety?
• What Does NGATS do for Capacity?
• New Separation Standards in Terminal Airspace?
• Wake Vortex Separation Reduction?
2
CATSR
What has Changed since 1947?
•Transonic vs. Subsonic Aircraft
•40,000 ft vs. 20,000 ft Altitude
•Avionics:
• Flight Management Systems
• Required Navigation Perf.
0.1nm
• Required Time of Arrival
• Traffic Collision Avoidance
System – On the Aircraft!
• AOC Data Links
• Zero Visibility Landing
Systems
•ATC radar Separation
•WHAT HAS NOT CHANGED
• Air Traffic Controllers
talking to Pilots using WW II
AM Radio Technology
3
CATSR
Some Little Discussed Facts
•Modern Jet Aircraft “Gate-to-Gate”
Travel Time is the Same or Longer
than Propeller aircraft (DC-6 circa
1947) for many routes in NE Triangle
• Typical Jet Aircraft is 70%
Faster and fly's 80% Higher
•Jet Aircraft can fly Over most bad
weather
•Modern Commercial Jet Aircraft can
Land in Very Low Visibility
•Airport Congestion Causes Most
ATC Delays and Airline Schedule
Padding Masks Real “Gate-to-Gate”
Delay
4
CATSR
Today’s Lack of Predictability is
Predictable!
5
CATSR
Outline
• What has Changed in 50 Years?
• Safety is the Underlying Capacity Constraint
• Current Safety Trends
• Airport Arrival – Departure 90% CEP
• What are the Underlying Causes of Delay?
• Too Many Scheduled Flights into Too Few Runways
– Average Aircraft Gauge Too Small
– Stochastic Queuing Delays Too Inefficient
– 80-90% Max Capacity Safety and economic Optimum
• What Does NGATS do for Safety?
• What Does NGATS do for Capacity?
• New Separation Standards in Terminal Airspace?
• Wake Vortex Separation Reduction?
6
CATSR
Part 121 (Scheduled Commercial)
Accident Rates are Increasing
2.5
2
y = 0.0533x + 1.0647
1.5
1
0.5
06
20
05
20
04
20
03
20
02
20
01
20
00
20
99
19
98
19
97
19
19
19
7
96
0
95
c ount per million operations
My filtered
part-121
Analysis
from Zohreh
Nazeri,accidents
PhD GMU 2007
CATSR
Safety at Principle Network Nodes
(i.e. Airports) is the Capacity Constraint
CATSR
• Aircraft Safety Separation Time over the
Runway Threshold sets the ATS Capacity
Limits
• Critical Technical Parameters that Define
Network Capacity:
•
•
•
•
8
Runway Occupancy Time (ROT)
Landing Aircraft Inter-Arrival Time (IAT)
Capmax = 90 sec IAT at 10-3 PSRO = 40 Arr/RW/Hr
Queuing Delay Onset at ~ 80% = 32 Arr/RW/Hr
limit for Predictable Performance
Data Analysis Process to Estimate:
IAT, IAD and ROT pdf’s
Airplane i
Threshold
Airplane i+1
Aircraft Type
Heavy
Large
Large
Small
Runway
Threshold
10:23:14
10:24:28
10:26:16
10:28:32
Leave Runway
10:24:04
10:25:13
10:27:12
10:29:28
...
...
...
Col. Clint Haynie, USA PhD., 2002
9
Yue Xie, PhD. 2005
CATSR
ROT vs. IAT to find Simultaneous Runway
Occupancy (SRO) Probability: est to be ~ 2 / 1000 CATSR
Runway
Occupancy
Time
(sec)
SRO
Region
Inter-Arrival Time (sec)
10
•Detroit Metropolitan Airport (DTW)
• Freq (IAT < ROT) ~= 0.0016 in peak periods and
0.0007 overall (including non-peak periods - 1870 total samples)
• IMC: 1 / 669= 0.0015 in peak periods
• Correlation coefficient = 0.15
[Babak, Shortle and Sherry, 2006]
How Will NGATS change these Distributions ?
Runway
Occupancy
Time
(sec)
New
Avionics &
Procedures
Existing Avionics
and Slot Controls
Inter-Arrival Time (sec)
11
Changes in FAA Procedures, Airport Slot
Controls and New Avionics Will Improve
BOTH Safety and Capacity
CATSR
DTW CEP* 90% (2000-2003)
Calculated Capacity (Today) and Actual Throughput
Optimum Rate
140
Calculated Capacity - Today
Arrivals per Hour
120
Facility Reported Rate - DTW
(arrivals, departures per hr)
92,92
CEP 90% as a
Measure of NAS
Network Node
Efficiency
100
80
60
Infrequent
Most Frequent
40
20
Each symbol represents actual
traffic during a single hour
0
0
20
40
60
80
100
120
140
Departures per Hour
IFR Rate
140
140
120
120
100
76,92
Arrivals per Hour
Arrivals per Hour
Marginal Rate
80
60
40
20
70, 66
80
60
40
20
0
0
20
40
60
80
100
Departures per Hour
12
100
120
140
0
0
20
40
60
80
100
Departures per Hour
120
140
* Contour of Equal
Probability
CATSR
EWR CEP 90% (2000-2003)
Calculated Capacity (Today) and Actual Throughput
A New Metric for BOTH Safety and Capacity Efficiency !
Optimum Rate
80
Calculated Capacity - Today
Facility Reported Rate - EWR
(arrivals, departures per hr)
Arrivals per Hour
42, 42
60
NGATS
needs to
shrink the
90% CEP
40
Infrequent
Most Frequent
20
Each symbol represents actual
traffic during a single hour
0
0
20
40
60
80
Departures per Hour
Marginal Rate
IFR Rate
80
60
Arrivals per Hour
Arrivals per Hour
80
40, 40
40
20
33, 33
40
20
0
0
0
20
40
60
Departures per Hour
13
60
80
0
20
40
60
Departures per Hour
80
CATSR
Outline
• What has Changed in 50 Years?
• Safety is the Underlying Capacity Constraint
• Current Safety Trends
• Airport Arrival – Departure 90% CEP
• What are the Underlying Causes of Delay?
• Too Many Scheduled Flights into Too Few Runways
– Average Aircraft Gauge Too Small
– Stochastic Queuing Delays Too Inefficient
– 80-90% Max Capacity Safety and economic Optimum
• What Does NGATS do for Safety?
• What Does NGATS do for Capacity?
• New Separation Standards in Terminal Airspace?
• Wake Vortex Separation Reduction?
14
CATSR
Queuing Delays set the Practical Capacity
Limitation set by Safety Separation Standards
•Sched.
Synch can
reduce Delay
by ~50%
15
20
Expected Delay (number of slots)
•Lack of Schedule
Synchronization
and 90 second
IAT generate
Queuing Delays
above about 80%
of Maximum
Runway Capacity
CATSR
18
16
Random arrivals
Bank size = 3
Bank size = 5
Bank size = 10
Optimum bank size
14
12
10
8
6
4
2
0
50
55
60
65
70
75
80
85
Number of Slots Filled (100 total)
90
95
100
NGATS Does Nothing about Too Many Flights on Small Aircraft:
Passengers Pay the Price in Flight Delays and Cancellations
CATSR
JFK Summer 2007 Departures
FAA Announced Departure Rate
(weekday AVG +/- 2)
Airline's Scheduled Departures
Flight Departures per 15 Minure Epoch
25
20
15
AVG ADR
10
5
0
0
5 AM
20
10 40
AM
3 PM
60
8 PM
80
24 Hours in 15 min. Epochs
16
Midnight
100
120
JFK Average Delay Profile (2006)
CATSR
Delay per Flight (minutes)
JFK
80
60
40
20
0
-20
-40
0
5
10
15
Time of Day (hour)
17
20
Delay Incurred at Major Airports
Propagate Network Wide (Summer 2005)
CATSR
Total Delay Ordered by Arrival Delay at Outbound Destination. (minute)
20,000 Flight Hours
1450000
850000
Airport Delay
Early-arrival Gap
Inbound Delay
Airborne Delay
650000
Arrival Delay at Outbound Dest.
Total Delays (minute)
1250000
1050000
450000
250000
50000
-150000
-350000
34 OEP Airport
18
[Ning Xu GMU 2007]
PDX
MEM
SAN
SLC
STL
PIT
TPA
SFO
MDW
CLE
CVG
FLL
SEA
BWI
LAS
LAX
MIA
PHX
DCA
MCO
CLT
IAD
IAH
LGA
JFK
BOS
DEN
DTW
MSP
PHL
EWR
DFW
ORD
ATL
-550000
Air Transportation System is Designed
to Move Passengers and Cargo
Passenger Tier Performance = f (Vehicle Tier Performance, Passenger
Factors i.e. Aircraft Gauge, Load Factor, Cancellations)
19
D. Wang GMU
PhD 2007
CATSR
Passenger Total Delay – Airports
•
•
CATSR
10 of the OEP-35 airports Æ 50% Total EPTD
some airports significantly impact Passenger Delay more than
others (e.g. ORD, ATL, DFW and MCO)
50%
Closed Network of OEP35 Airport in 2004
20
D. Wang GMU
PhD 2007
200 Routes generate 50% of Total Passenger Delay
CATSR
What Does NGATS Do for These Routes?
•
•
17% of the 1044 routes between OEP-35 airports Æ 50% Total EPTD
LGA, JFK, EWR, PHL connected Routes Æ 11 out of top 20 routes
50%
Closed Network of OEP35 Airport in 2004
21
D. Wang GMU
PhD 2007
Minimum Economic Cost is at ~90% Max. Capacity
Cost to Nation's Economy ($B)
$45
Slot Reductions Imposed
at Top 35 Airports
Sum of Both
Costs ($B)
$40
$35
Costs Resulting From Reducing
Airport Landing Slots
$30
$25
$20
Some Costs Approximated,
Other Costs Not Included
Costs Resulting from Passenger
Delays and Flight Cancellations
$15
$10
$5
$0
0.0%
2.5%
5.0%
7.5%
10.0%
12.5%
15.0%
17.5%
20.0%
Percent of Slots Withheld at Top 35 Airports
22
Donohue and
Shaver 2008
CATSR
Summary on Capacity
• ~40 Arrival per Runway per Hour is current
Safety Maximum
• ~32 Arrivals per Runway per Hour is ONSET of
Queuing Delays & Optimum Predictability and
Economic Utilization Rate
• How will NGATS Technology/Procedures Change
This?
• Market Allocated Scheduled Landing/Departure
times at 90% Max Capacity Will Be Required to
Achieve Optimum Network Performance
• EVEN WITH NGATS!
23
CATSR
Outline
• What has Changed in 50 Years?
• Safety is the Underlying Capacity Constraint
• Current Safety Trends
• Airport Arrival – Departure 90% CEP
• What are the Underlying Causes of Delay?
• Too Many Scheduled Flights into Too Few Runways
– Average Aircraft Gauge Too Small
• What Does NGATS do for Safety?
• What Does NGATS do for Capacity?
• New Separation Standards in Terminal Airspace?
• Wake Vortex Separation Reduction?
24
CATSR
IS NGATS Adequately addressing the Capacity
related Safety Problems?
CATSR
• What is the Wake Vortex Warning System?
• What is the ADS-B Back-up to GPS for aircraft without
Inertial Guidance?
• ADS-B (out), 4-D trajectories, RNP-0.1
• Good for Airline Fuel Efficiency but NOT ENOUGH for
Increasing System Network Capacity!
• How will Aircraft Separation in Terminal Airspace and on
the Runways be REDUCED by X3?
• Closely Spaced, Fully-coupled Autopilot Formation Landings with
2 – Lane Runways?
• Can Closely Spaced Airports be Cross-linked with
Runway Independent Air Transport (MegaPlex System
Network Nodes)?
• New Generation of Heavy Lift Helicopters?
25
Outline
• What has Changed in 50 Years?
• Safety is the Underlying Capacity Constraint
• Current Safety Trends
• Airport Arrival – Departure 90% CEP
• What are the Underlying Causes of Delay?
• Too Many Scheduled Flights into Too Few Runways
– Average Aircraft Gauge Too Small
• What Does NGATS do for Safety?
• What Does NGATS do for Capacity?
• New Separation Standards in Terminal Airspace?
• Wake Vortex Separation Reduction?
26
CATSR
The Predicted Growth in Aviation Demand is based on
Passenger Demand NOT Aircraft Operations
27
CATSR
• Aircraft Gauge, Schedule Synchronization and Network
Load Balancing will Be Required
• Annual Combinatorial Clock Slot Auctions ?
• Larger Aircraft will be required to meet X2 or X3 demand
• Business Jet and VLJ Air Taxi Service will emerge to
compete with Commercial aviation due to current System
Failure
• May not be able to put the Geni back in the Bottle
• Environmental Implications?
• New Aircraft (e.g. B 787) should be Environmentally
Friendly (Emissions/passenger/mi.?)
• US airlines are not currently ordering them due to
poor financial position
• New Public Policy will be needed to Deal with these
Complex Adaptive System Problems
• NEXTGEN System not addressing these issues
Center for Air Transportation System Research
Publications and Information
• http://catsr.ite.gmu.edu
– Other Useful Web Sites
• http://mytravelrights.com
• http://gao.gov
• http://www.airconsumer.ost.dot.gov
28
CATSR
CATSR
BACKUP Material
29
Trends for Incidents Associated with Accidents
Trends of the factors in incident databases
• Pilot factors decreasing
• Aircraft factors slowly decreasing
• ATC factors increasing
30
800
600
200
0
ATC incidents in FAA/OED data, Terminal
40
30
y = 0.0824x + 29.716
10
0
count per million
operations
40
20
y = -3.8007x + 683.79
400
50
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
count per million operations
ATC primary factors in ASRS reports
Aircraft primary factors in ASRS reports
1000
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
y = -7.1868x + 123.33
PhD GMU 2007
count per million operations
160
140
120
100
80
60
40
20
0
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
count per million operations
Pilot primary factors in ASRS reports
Analysis from Zohreh Nazeri,
35
30
25
20
y = 1.4581x + 18.118
15
10
5
0
95
96
97
98
99
00
;01
02
03
04
CATSR
ATC factors – Communication Errors
CATSR
Top complexity factors associated with ATC factors:
• number of aircraft in airspace
• runway configuration
-- airspace design
-- controller experience
% commerrors
Top-10 traf fic complexity f actors associated w ith
communcation errors
40.00%
30.00%
20.00%
10.00%
ot
he
r
b
#a lan
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ai
rs
pa
ce
,# #
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ot
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r
he
, e spa
r
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er
,o
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nc the
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e, r
y
ot
co
he
nf
r
ig
,o
th
er
#a ai
/c rsp
,r
w ace
y
co
nf
ig
0.00%
Analysis from Zohreh Nazeri,
PhD GMU 2007
These factors will get worse over time:
• air transportation is projected to grow for the next 10 years
31
• majority of controllers will retire within next few years
Aircraft factors
CATSR
“Flight Control System” problems growing
Other aircraft factors decreasing
Aircraft flight control system problems
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
03
20
02
20
01
20
00
20
99
19
98
19
97
19
96
19
95
y = 0.4037x - 0.2704
19
ar
i ng
nd
c ount per m illion operations
so
r
La
As
se
m
Ge
bly
in g
W
es
pr
m
Co
ion
ll is
Co
Sy
s te
an
Av
o id
lon
Py
ll e
/
ce
Na
ce
ac
hm
att
tr o
on
tC
igh
Fl
m
t
en
m
ys
te
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
lS
tren d lin e slo p
Growth of aircraft problems in SDRS data
Analysis from Zohreh Nazeri, PhD GMU 2007
32
FAA: 2 Separate Functions with an
Inherent Conflict of Interest
CATSR
• A Safety Regulatory Agency
• Airlines
• Aircraft Manufactures
• An Air Traffic Management Operator
• Safety Oversight of ITSELF
• Many Industrialized Nations have Separated
this Function from the Gov’t Oversight Agency
– Australia, Canada, Germany, New Zealand, United
Kingdom, etc.
33
My Opinion on WHY FAA has and
Will Continue to Fail
CATSR
• FAA Organization, Culture and Engineering
Expertise is Totally Inadequate to the Task of
Designing, Acquiring and Maintaining a Modern
Telecommunications System
• Exhibits Monopolist Behavior
• Not Held Accountable!
• It is NOT in the Self Interest of a Wealthy, and
Politically Powerful Union (NATCA) that has:
•
•
•
•
•
34
Total job Security (civil service protection)
Ability to Directly Lobby with the Public and Congress
VERY HIGH PAY and Wealthy PAC (some >$200,000/yr)
Short Work Hours (< 5 hours/day)
Low Educational Entrance Requirements (High School)
• No Accountability for Poor System Performance
EWR Free-Market Fleet Mix Appears to be
Far from Optimum
35
CATSR
Summary of European Passenger Bill of Rights http://news.bbc.co.uk/1/hi/business/4267095.stm
•
Overbooked Flights
•
•
•
•
•
•
•
Offered a refund of your ticket, along with a free flight back to your initial point of
departure, when relevant. Or, alternative transport to your final destination.
Rights to meals, refreshments, hotel accommodation if necessary, even free e-mails or
telephone calls.
– Airlines can only offer you a refund in the form of travel vouchers if you agree in
writing
Refunds may also be paid in cash, by bank transfer or cheque
If the reason for your flight's cancellation is "within the airline's control", it must pay
compensation.
Compensation for cancellations must be paid within seven days.
Delayed Flights
•
36
Passengers can now get roughly double the existing compensation if they are bumped off a
flight.
– Compensation must be paid immediately.
– These passengers must also be offered the choice of a refund, a flight back to their
original point of departure, or an alternative flight to continue their journey.
May also have rights to meals, refreshments, hotel accommodation if necessary even free emails, faxes or telephone calls.
Cancelled Flights
•
•
CATSR
•
Airline may be obliged to supply meals and refreshments, along with accommodation if an
overnight stay is required.
If the delay is for five hours or more, passengers are also entitled to a refund of their ticket
with a free flight back to your initial point of departure if this is relevant.
Air Transportation is Characterized as a
Complex Adaptive System (CAS)
Fleet
Attributes
Fleet
Costs
Trips flown
by fleet
CATSR
Fleet
Revenue
Effect on
GDP
Passenger
Delays
Delays
Airport
Capacity
Enroute
Capacity
Flight Delays
&
Cancellations Offered
Schedule
Inconven
ience
Reference
demand
37
Airline
Profits
Effective
Price
Flights by
Fleet
Market
Clearing
Ticket
price
Aircraft
Fleets
Active
fleet
Effective
price by
length of trip
Baseline
Demand
Bengi Mezhepoglu, PhD
in progress