Tailored Arrivals & the En Route/
Descent Advisor
Concept, Initial Field Trials, and Future
Research Directions
SAE Aerospace Control and Guidance Systems Committee
Subcommittee D – Dynamics, Computations & Analysis
Crown Plaza, Williamsburg
Williamsburg, VA
October 13, 2006
Rich Coppenbarger
Automation Concepts Research Branch (AFC)
NASA Ames Research Center
Moffett Field, CA
1
Outline
 Tailored Arrivals: Concept, Benefits, Background
 Trajectory Specification and Role of EDA Automation
 Oceanic Tailored Arrivals (OTA) Field Trials
•
Overview
•
Profiles
•
Procedures
•
Data Collection
•
Initial Results
 Summary
2
What is a Tailored Arrival?
An adaptable trajectory solution that enables an efficient,
continuous descent from cruise altitude to runway threshold
Ideally:
• Allows continuous, near idle descent
• “Tailored” by ATC through selection of speed, altitude and route constraints
- Avoid conflicts
- Meet sequence and schedule constraints
- Avoid weather, terrain, and restricted airspace
- Acknowledge individual aircraft operational constraints
• Given as a single clearance well prior to TOD
• Coordinated across facility boundaries
• Delivered by data-link for minimal workload
• Loaded into and flown by aircraft FMS
3
Why Tailored Arrivals?
 Reduced fuel burn
 Reduced noise
 Reduced emissions
 Reduced controller and pilot workload
 Improved arrival trajectory certainty and situational awareness
 Improved engine life (due to fewer level-off power cycles)
 Provide a return on existing airline avionics investment
 Acquire immediate benefits in low density airspace using currently deployed systems
 Blaze a trail towards next-generation ATC concepts and systems (NGATS 2025)
Measured benefits from related field trails
(e.g., Australian TA, Louisville CDA):
• 300 - 800 lb fuel savings per flight
• 2 - 5 minutes time savings per flight (under non metering conditions)
• 3 – 6 dB average noise reduction per flight
4
Problem Illustration
Actual SFO-Arrival
Tracks observed on
2/3/06
B744
B772
5
CDA Field Trials, Louisville
Team: FAA, Boeing, NASA, MIT, UPS, Volpe Center, Purdue University
Operation:
• 2002 Trial:
- Select UPS B767 flights flew RNAV/VNAV CDA from TRACON entry to runway threshold
- Two-week flight test: 10/29/02 – 11/9/02
- Two similar flights per night: 1 flew CDA, following flew conventional step-down approach
- CDA with low/idle engine thrust inside SDF TRACON
- Clearance issued by voice and entered manually into FMS
• 2004 Trial:
- Select UPS B757 & B767 flights flew RNAV/VNAV CDA from cruise to runway threshold
- Two-week flight test: 9/14/04 – 9/25/04
- 12 flights per night flew CDA procedure
- CDA with low/idle engine thrust inside Indy Center & SDF TRACON
- Clearance issued by voice and selected from FMS database
Findings:
• 3 – 6 dBA noise reduction with CDA
• .5 – 1.5 min reduction in nominal flight time
• 450 – 550 lb fuel reduction (validated in simulator)
6
Australian TA Field Trials
Team: ASA, Boeing, Qantas, Air Traffic Alliance (EADS, Thales, Airbus)
Operation:
• Qantas B747 & A330 flights on Singapore to Sydney and Singapore to Melbourne routes
• TA procedure executed from approx 140 nmi (30 min) from airport to runway threshold
• 6-month flight test (April to September, 2004) involving total of 80 flights
• Clearances generated on ground and communicated with TAAATS ground system over CPDLC
• TA clearance given at least 20 min prior to TOD, to allow adequate time for crew review
• TA procedure replicated normal arrival procedure (STAR) with additional speed and altitude constraints
• Most of TA procedure loaded into FMS from uplink message (some elements sourced from FMS database)
• Time constraints at waypoints up-linked for small sample of flights to test RTA capabilities
Findings:
• Accurate ETA predictions by FMS from pre-TOD over 40-min time horizon (+/- 30 sec)
• Fuel-burn results processed by Qantas in post-trial simulation: 400-800 lb/flight savings
• Numerous operational issues discovered, some resolved during test
7
How will Tailored Arrivals Work?
FANS (or other)
4
TA trajectory
received and
loaded into
FMS upon pilot
concurrence
5
TA trajectory
flown with FMS
6
Aircraft downlinks
parameters for ATC
trajectory
confirmation/tuning
ATOP/ERAM
3
CPDLC
TA clearance delivered to
aircraft over data-link
1
EDA
Ground automation
generates TA trajectory
clearance
7
TA procedure broken off
if trajectory can’t be
continued for any reason
2
TA clearance coordinated
across ATC
domains/systems
8
EDA Component
TMA plans
sequence and
schedule to
TRACON meter fix
EDA generates
advisories to
meet TMA
schedule
(absorb delay)
Vertical advisories
involve cruise speed,
descent speed, and
altitude
Turn-back point
TOD
• Cruise Speed
• Cruise Altitude
Capture waypoint
• Descent Mach
Horizontal
advisories involve
path stretching
• Descent CAS
BOD
Meter
Fix
TRACON
Runway
TRACON
9
TA Trajectory Specification
Basic TA clearance defines lateral
routing and one or more crossing
restrictions through IAF (e.g. Menlo)
Initial cruise/decent speeds
and TOD will be dynamically
controlled by EDA
10
Oceanic Tailored Arrivals Field Trials
11
Central-East Pacific (CEP) Route Structure
12
Participants
 Boeing
•
•
•
•
Airborne integration
Profile development
End-to-end systems validation
Airline/community advocacy
 NASA
•
•
•
•
EDA and Wx data systems development, integration, and
testing (AFC & AFD)
Human procedures development and testing (TIH)
Profile development and analysis (TIH & AFC)
FAA advocacy (AFC)
•
•
•
•
Field-test endorsement and permission
Facility and controller access
ATOP system upgrades
EDA systems integration
 FAA
 UAL
•
•
•
Field-test endorsement and participation
AOC coordination
Flight crew information/training
13
Quantitative Objectives
 Validate assumed benefit mechanisms with real-world data:
• Fuel savings
• Noise reduction in TRACON (for near-term application, we want to
specifically address noise signature over OSI)
• Emissions reduction in TRACON
• Engine stress reduction
 Study underlying trajectory prediction accuracy
• Effect of data exchange (primarily winds) on trajectory prediction accuracy
• Comparison of EDA and FMS trajectory predictions
• Comparison of EDA trajectory predictions with actual flight track
• Comparison of FMS trajectory predictions with actual flight track
14
Scope
 Trans-pacific UAL FANS 1/A arrival operations.
 Phase 1 involved UAL 76 en route SFO from HNL via the fixed Central-East
Pacific (CEP) track system.
•
Conducted August 17 - September 6, 2006
•
Events initiated approx 2-hours prior to 5:20 AM (local) arrival at SFO
•
Stop date driven by UAL equipage swap to non-FANS aircraft type.
 Phase 2 expected to commence November 2006.
•
Continue with UAL 76 one night per week
•
Hoping to transition to UAL B-777 and B-747 arrivals from Asia/Australia via
oceanic flex tracks defined by ZOA’s Pacific Coast Track System (PACOTS).
•
FAA approval is pending
15
Scope (continued)
 Key events:
•
Up-link of basic OTA clearance that coveys waypoints , speed/altitude
constraints at waypoints, approach procedure, and runway assignment.
•
Up-link of cruise and descent winds from ground-based model (NOAA RUC-2)
•
Up-link of EDA-computed descent speed schedule
•
Down-link of ADS-C reports at a 2-min periodic rate
16
Profile Development Process
 Designed CDA profiles to overlay efficient lateral routes
 Coordinated with ZOA/NCT on required airspace and procedural
constraints
 Tested and refined FMS/VNAV profiles in flight simulation at UAL,
Boeing, NASA Ames
 Observed actions by line pilots in managing energy state, i.e., controlling
both path and speed under various wind conditions
 Developing a “one size fits all” profile has proved to be challenging
• B-777 tends to carry excess energy in managing to path, thereby requiring
aggressive drag deployment actions (speed brakes, flaps, gear)
• B-747 tends to require additional energy input (thrust) to maintain path,
especially when encountering unexpected head winds
17
Basic OTA Clearance Up-Link
At CINNY cleared to:
– BRINY – 11000/240kts
– OSI
- 7000A
– MENLO – 200kts / 4500A
– ILS28R Approach
– Runway 28R
Clearance relies on published
approach procedure
18
Data Collection (Quantitative)
Source
Elements
Frequency
ADS-C
• Position group (lat/long, altitude, time stamp)
• Weather group (wind speed, wind direction,
temperature)
• Earth reference group (ground speed, vertical rate,
track angle)
• Air reference group (Mach, heading)
• Projected intent (ETAs at all downstream
waypoints)
1/ (2 min)
ZOA Host Track and FP
• Position
• Ground speed, track heading
1/(12 sec)
NCT ARTS Track and FP
• Position
• Ground speed, track heading
1/ (5 sec)
EDA outputs
• Trajectory predictions
• Advisories
RUC
• Grid wind speed/direction
• Grid T, P
SFO Microphone
• Noise level
Event based
1/hr
10 Hz
19
Microphone Deployment
KSFO
Permanent noise
monitor sites
CEPIN
AXMUL
Deployed
portable
noise
monitors
MENLO
Courtesy SFO Noise
Abatement Office
OSI
20
Procedures: Basic Event Series
1)
Approx 2 hours prior to SFO arrival
flight crew downlinks intent to
participate in OTA trials
21
2)
Controller modifies ADS-C reporting
contract to capture data at 2-min
intervals
22
3)
Controller up-links Basic OTA clearance
via CPDLC
•
At [CINNY] cleared [ROUTE CLEARANCE]
•
[ROUTE CLEARANCE] includes lateral
route, crossing restrictions, approach
procedure, and runway assignment
23
4)
Flight crew loads Basic OTA clearance
into FMS and reviews
•
If acceptable, crew downlinks “wilco”
and activates route in FMS
•
If unacceptable, crew downlinks
“unable”
24
5)
Updated cruise/descent winds, based on
CTAS/RUC, are sent to AOC by EDA test
engineer for uplink and FMS auto-load
•
Cruise wind @ CINNY
•
Descent winds @ OSI for 100 ft, 10K ft,
FL 180, FL 250
25
6)
For EDA and scenarios, test engineer
sets metering time at TRACON
boundary
• EDA cruise/descent speeds are
computed and up-linked, e.g. FMC
SPEED SCHEDULE: CRZ [.83], DES
[.83/286]
• Upon acceptance, flight crew enters
EDA instruction into FMS
26
7)
OC4 hands-off to ZOA Sector 35
•
CPDLC services drop off
•
ATOP ADS contract automatically
terminated upon hand-off
27
8)
Controller issues pilot discretionary
descent clearance down to 8,000 ft
along OTA profile
TOD
28
9)
NCT controller clears aircraft to
continue OTA descent and provides
approach clearance
TOD
29
10) Localizer intercept, glideslope capture, and landing
TOD
30
Initial Findings from OTA Trials
 Limited data set, not statistically significant
 Qualitative findings have proven indispensable for shaping concept and
refining procedures in preparation for follow-on R&D
 Quantitative analysis still very much a work in progress
 Fuel, noise, and emissions analyses are currently underway by Boeing
31
Initial Findings - Quantitative
 FMS arrival time prediction to TRACON boundary (at BRINY)
 EDA arrival time prediction to TRACON boundary
 EDA trajectory prediction performance
• Altitude error
• Cross-track error
32
OTA Phase 1 Run Statistics
OTA
Attempted Successful
Successful
Successful**
Opportunities
OTAs
Route Uplink Wind Uplink CDA (ZOA)
21
17
Basic
EDA
7
14
17
Basic EDA
3
14
Successful**
CDA (NCT)
8*
16*
13
Basic
EDA
Basic
EDA
Basic
EDA
Basic
EDA
3
14
3
10
6
10
0
8
* Data not yet available for 1 flight so it is not included
** Non CDA success characterized by short level-off segments.
33
Nominal Vertical Profile (Non OTA)
August 19, 2006
34
Vertical Profile with OTA Procedures
August 29, 2006
EDA-assigned
speed schedule =
.84 M, 290 kt CAS
35
FMS Predictions to BRINY
COPPI
COSTS
CREAN CINNY
(655 nm to BRINY)
(355 nm)
(190 nm)
BRINY
(70nm)
200
180
ADS-C FMS intent
data captured
through ATOP
160
140
120
100
80
60
FMS
Prediction
Error
(sec)
40
20
Late
0
-20
Early
-40
17-Aug
-60
25-Aug
-80
26-Aug
-100
27-Aug
-120
28-Aug
-140
29-Aug
-160
30-Aug
-180
-200
120.00
100.00
80.00
60.00
Time to BRINY
(Minutes)
40.00
20.00
0.00
36
FMS Predictions to BRINY (continued)
COPPI
COSTS
CREAN CINNY
(655 nm to BRINY)
(355 nm)
(190 nm)
BRINY
(70nm)
200
ADS-C FMS intent
data captured
through Boeing
ACAT
180
160
140
120
100
80
60
40
FMS
Prediction
Error
(sec)
20
Late
0
-20
Early
-40
-60
31-Aug
-80
1-Sep
-100
2-Sep
-120
3-Sep
-140
4-Sep
-160
5-Sep
-180
-200
120.00
100.00
80.00
60.00
Time to BRINY
(Minutes)
40.00
20.00
0.00
37
FMS Predictions to BRINY
Aircraft at CREAN - Arrival Prediction for BRINY
2
Mean = 8 seconds late
Max Early = 20 seconds
Max Late = 38 seconds
Std Dev = 20
# of
Aircraft
1
0
more than 40 to 30
40
30 to 20
20 to 10
10 to 1
0 to 10
Early
10 to 20
20 to 30
Late
30 to 40
more than
40
Seconds
* Includes only OTA w/EDA flights with adequate predictive data at CREAN and
successful wind uplinks
38
EDA Predictions to BRINY
Aircraft at CREAN - Arrival Prediction for BRINY
3
Mean = 24 seconds late
Max Early = 2 seconds
2
# of
Aircraft
Max Late = 50 seconds
Std Dev = 16
1
0
more
than 40
40 to 30
30 to 20
20 to 10
10 to 1
0 to 10
Early
10 to 20
20 to 30
Late
30 to 40
more
than 40
Seconds
39
Comparisons of FMS and EDA
Predictions to BRINY
OTA EDA-Lite
3
# of
Aircraft
Mean = 24 seconds late
Max Early = 2 seconds
2
1
0
more 40 to 30 30 to 20 20 to 10 10 to 1
than 40
0 to 10 10 to 20 20 to 30 30 to 40
Early
Late
more
than 40
Max Late = 50 seconds
Std Dev = 16
Seconds
FMS
Mean = 8 seconds late
Max Early = 20 seconds
2
# of
1
Aircraft
0
Max Late = 38 seconds
Std Dev = 20
more 40 to 30 30 to 20 20 to 10 10 to 1
than 40
0 to 10 10 to 20 20 to 30 30 to 40
Early
Late
more
than 40
Seconds
40
EDA Trajectory Prediction
Performance
EDA Flights
Included
ALTITUDE ERROR
CROSS TRACK ERROR
Mean
(ft)
Max
(ft)
Std Dev
(ft)
Mean
(nm)
Max
(nm)
Std Dev
(nm)
All Flights
496
3908
725
.45
3.42
.64
Flights with
Wind Uplink
446
3154
668
.37
3.42
.71
41
EDA Trajectory Prediction
Performance
42
Summary
 Tailored Arrivals concept offers compelling, simultaneous benefits: fuel, noise,
and emissions reduction through CDA.
 Challenge is to plan and successfully execute CDA trajectories in the presence of
congested and complex traffic conditions. This is where the true benefits are!
 Predictive ground-based automation capable of generating conflict-free, flowrate-conformant solutions from cruise to runway is the key to the problem.
 Existing EDA prototype automation is a start, but needs further algorithm
development with extension into the lower airspace domain.
 Tailored Arrivals concept is cross-cutting to several basic NGATS technology
elements: FMS/data-link integration, air-ground data exchange, trajectory-based
operations, time-based metering with separation constraints.
 Oceanic automation (air and ground) has provided an excellent environment for
validating Tailored Arrivals procedures and system interoperability.
 Current field trials have been highly successful and will be used to identify
immediate procedural improvements while supporting long-term R&D goals.
43