Transcript DFW Median TRACON Flight Times

Estimating the En route Efficiency Benefits Pool
Dan Howell, Michael Bennett, James Bonn, CNA Corporation
Dave Knorr, FAA AOZ-40
June 23, 2003
CNA
Outline
• Sources of En route Inefficiency
• Inefficiency and excess distance
• Excess distance vs. traffic load in a center
• National excess distance benefits pool
- basic calculation
- accounting for conflicts
- comparison with other studies
• Future Benefits Framework
CNA
Programs expected to contribute to
delay and flight efficiency savings
Program/Capability
ADS-B
En Route
Terminal
Surface
Program/Capability
X
X
X
Medium Intensity Airport Weather
System (MIAWS)
X
Power Systems
ASDE-X, ASDE-3
CPDLC
X
CRCT
X
En Route
Communications
Gateway (ECG)
X
ERAM
X
DRVSM
X
X
X
X
X
Radio Frequency Interference
(RFI)
X
X
Required Navigation Procedures
(RNP)
X
X
X
X
X
X
X
X
X
Terminal Radars (ASR-9 SLEP,
TDWR)
TMA
Local Area Augmentation
System (LAAS)
X
URET
Wide Area Augmentation System
(WAAS)
X
NAS Infrastructure
Management System
(NIMS)
X
X
X
X
X
X
Chart from FAA ASD-400 presentation
X
X
Integrated Terminal
Weather System (ITWS)
X
Surface
Additional RNAV Routes
Traffic Flow Management (TFM)
NEXCOM
Terminal
X
Precision Runway Monitor (PRM)
X
Departure Sequencing
Program (DSP)
En Route
Winds Aloft Prediction in Nonconvective weather
X
X
X
X
Sources of En route Inefficiency
CNA
Model
Inefficiency Source
• Route Structure
• Conflict Avoidance
• Terminal Congestion
• Sector Capacity
• Severe Weather
Example of En route inefficiency due to
Terminal Congestion
Conflict
Avoidance
Sector
Capacity
Severe
Weather
Terminal
Congestion
Route
Structure
CNA
Inefficiency and excess distance
In order to study inefficiency
we must refine definition to
examine benefits.
Actual or Planned track
Great Circl e path
We chose to examine excess distance over great circle.
Advantages:
shows less variation due to wind (than flight times)
does not require flight profile data (like fuel burn)
Disadvantages:
not as direct a measure of benefit as time or fuel burn
neglects inefficiency due to speed control
Excess distance and traffic load
Average excess distance per flight (nmi)
CNA
More Efficient Routes More Capacity or less
More Directs
(RNP, airspace redesign)
(URET,PARR,D2)
conflicts (RVSM, URET,
Data link)
10
Opportunity
Regime
Route Structure
Regime
Congestion
Regime
0
0
20
40
60
Percent of maximum center traffic
80
100
Excess distance vs. traffic load
in different centers
CNA
ZOA - has higher traffic levels
- handles a higher proportion of arrivals and departures
than ZAB.
Average excess
distance per flight
(n. mi.)
20
More complex
route structure
15
ZOA
10
ZAB
Greater
susceptibility to
capacity-related
effects
5
0
0
20
40
60
80
Percent of maximum center traffic
100
CNA
National excess distance benefits pool
After removing foreign and round-robin flights, a good weather
day of ETMS track data contains ~50,000 flights.
~Entire flight
Calculated excess distance
using two methods
1
En route portion
2
50. nmi.
Actual or Planned track
Great Circle path
Method 1
~29 % of total excess
distance occurs in the
en route environment
Method 2
Metric
Actual
Plan
Actual
Plan
Mean (nmi)
28.5
22.0
9.3
10.0
Sum (nmi)
1,296,556
1,141,967
369,968
427,803
% flight
7.7
6.9
2.4
3.1
How much of this pool is recoverable?
CNA
Using FACET to Detect conflicts
•Used NASA FACET program to examine potential conflicts (5 nmi.) in both
flight plans and direct flights.
•FACET input for flight plans is field10 (used actual takeoff time)
•Only counted conflicts above FL180
Flight Plan Routing
Total Conflicts
Direct Routing
10,157
8008
0.47
0.37
# of planes with conflicts
12,012
10,412
% of planes with conflicts
28.0
24.3
Average conflicts per conflicted plane
1.69
1.54
Average conflicts per plane
More en route potential conflicts arise from aircraft on the current air route
structure than would be the case for direct routings.
CNA
Estimating conflict cost
Controller feedback suggested conflicts in en route environment were
resolved by lateral changes, as opposed to changes in speed or altitude.
Decided to calculate typical distance for lateral conflict resolution.
Conflict cost
depends on:
Potential
Conflict
1. Conflict radius
2. Conflict angle
3. Speeds
4. Resolution start
Original
Flight Path
Revised
Flight Path
q
CNA
Conflict cost (nmi.) as a
function of Conflict Angle
- Used conflict angles and plane speeds from FACET analysis
- Used min. conflict radius (5 nmi.) and buffered radius (10 nmi.)
- Used constant resolution start time (4 min before loss of separation).
Calculated minimum conflict cost (nmi.) vs. conflict angle.
CNA
Conflict Cost Results
Used conflict angle distribution from FACET detection analysis
Using minimum
Using buffered
Original excess distance pool
369,968 nmi
369,968 nmi
Mean excess distance per conflict
1.4 nmi
3.63 nmi
Total excess distance for conflicts
22,407 nmi
58,149 nmi
New excess distance pool
347,561 nmi
311,819
% of original pool diminished by
conflicts
6
16
Translating distance into annual dollars ($ = (distance/speed)*ADOC * (343 eff.days))
we find and annual savings for new pool of $699M - $786M
CNA
Comparison with other studies
Number of eligible flights
per day
Daily Benefit per
Eligible Flight
(min)**
699-786M
39,753
1.32 – 1.49
Delta (1996)
42M – 92M
2,000 (Delta Fleet)
1.58 – 3.46 (2)
NASA D2 study (1996)
107 – 279M
5399 - 9488
1.49 – 2.21 (2.8)
MITRE ETMS (2000)
~700M
29,045
1.81
MITRE TMAC (2000)
620M
31,000
1.50
557 – 652M
40,437 – 50,157
0.98 – 1.03
2692
(S. Region, over 750 nmi)
(3.8 in 2005)
7300 (regional pairs)
(5.6)
Study
FAA AOZ study (2002)
Seagull Technology (1998)
Annual Benefit
(dollars)*
FAA ASD S. Region (2002) – time savings for Direct/Wind
optimized
MITRE Flying times (2003) – using optimum time over 30 days
*The Current study and the Seagull Technology study are presented in 1998 dollars. Both MITRE studies were published in
January 2000 and use Air Transport Association cost values but do not specifically document a year. The NASA Ames study uses
a value of $29/minute without reference. The Delta Airlines analysis was published in 1996, but the reference to this study in the
NASA Ames document does not detail the reference year.
**The Daily Benefit in minutes column calculated by using dollar column and an average ADOC for Freight and Commercial of
$2327/hr, the numbers in parentheses are from the separate studies. They are different because of different aircraft mix and
ADOC values.
CNA
Future Benefits Framework
Can use current study to examine reasonableness of past
benefits estimates: recent URET study claimed a benefit that was ~7% of
this pool.
Long-term goal
A common single set of tools for benefits estimates that:
- addresses the sources of inefficiency (including capacity and weather)
- includes ability to validate with current data and conditions
- is widely available and open source for use in FAA and academia.