Tom G. Reynolds, Michael McPartland, Tom Teller & Seth Troxel Sponsor: Gary Pokodner, FAA Weather Technology in the Cockpit June 24, 2015 11 th USA/Europe Air Traffic Management Research and Development Seminar (ATM2015) Exploring Wind Information Requirements for Four Dimensional Trajectory-Based Operations* *This work was sponsored by the Federal Aviation Administration (FAA) under Air Force Contract FA8721-05-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the United States Government
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Exploring Wind Information Requirements for Four ......2015/06/12 · Honeywell Pegasus MCDU Winds/4D-TBO - 11 06/24/15 • More robust FMS simulation capability enabled validation
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Tom G. Reynolds, Michael McPartland, Tom Teller & Seth Troxel Sponsor: Gary Pokodner, FAA Weather Technology in the Cockpit
June 24, 2015 11th USA/Europe Air Traffic Management Research and Development Seminar (ATM2015)
Exploring Wind Information Requirements for Four Dimensional
Trajectory-Based Operations*
*This work was sponsored by the Federal Aviation Administration (FAA) under Air Force Contract FA8721-05-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the United States Government
Winds/4D-TBO - 2 06/24/15
Meter Fix
Time target @ Meter Fix; Wind updates
Actual winds
Wind Needs for NextGen Applications
RTA
Aircraft Winds
ATC/Airline
Ground Winds
Objective: Establish relationship of wind information accuracy to 4D-TBO and IM performance and hence identify wind needs to support them
• Many NextGen applications depend on access to high accuracy wind data – Required Time of Arrival (RTA) at a
meter fix under 4D-Trajectory Based Ops – Assigned Spacing Goal (ASG) between
aircraft under Interval Management (IM)
Winds/4D-TBO - 3 06/24/15
Performance Assessment
Wind Information Analysis Framework
Allows analysis of wind information impacts on range of NextGen applications Designed to be scalable wrt scope/fidelity & flexible wrt application
Wind forecast assumpt
ions
Wind Scenario Truth Forecast
Airc
raft/
Aut
omat
ion
Sim
ulat
ion
Stakeholder needs
ATC Scenario 4D-TBO IM
Wind Requirements
Identify combinations of wind data forecast model & look-ahead time which meet required wind info
quality goal
Perf
Met
ric
Wind Information Quality
Low
Med
High
Sampletargetperformance
Aver
age
fore
cast
err
or
Look-ahead time
Benign, Moderate,
Severe, Extreme
Model A B C
Req’d wind info
quality
Winds/4D-TBO - 4 06/24/15
Wind Information Implications Flow Diagram
1. Define scenarios of interest
2. Identify performance trade-space
3. Select target performance level
4. Do feasible combinations of performance drivers meet target level of performance?
Yes (wind error limit)
No
5. Do feasible combinations of wind
forecast model and look-ahead time meet error
limit?
Yes
No
Identified need for enhanced
automation and/or wind model
“or”
6. Define procedure/ConOps/supporting technology needs to get required wind info accuracy to aircraft
Perf
Met
ric
Wind Information Quality
Low
Med
High
Sampletargetperformance
Aver
age
fore
cast
err
or
Look-ahead time
Model A B C
Winds/4D-TBO - 5 06/24/15
• Analysis focused on impact of wind information accuracy on ability to achieve RTA for range of descent scenarios
4D-TBO Analysis Overview
MeterFix
Time target@ Meter Fix;
Wind updates?
Actualwinds
RTA
AircraftWinds
ATC/Airline
GroundWinds
RTA Compliance Error
Freq
uenc
y RTA 95%confidence
interval
0
Winds/4D-TBO - 6 06/24/15
• Nov/Dec 2011 flight trials of Alaska Airlines B737/GE flights into SEA
• Latest RUC winds uploaded to FMS approx. 70 mins prior to arrival
• RTAs assigned via aircraft/ATC negotiation
Baseline SEA Flight Trials*
σ = 11.4 secs
μ = 9.0 secs
RTA Compliance Performance (secs)Crossing Time – FMS RTA Time
Num
ber o
f Flig
hts
EARLY LATE
* Source: Wynnyk, C., and D. Gouldey, “2011 Seattle Required Time of Arrival (RTA) Flight Trials Analysis Report”, MITRE CAASD, July 2012
Flight trial data indicated importance of wind information for effective 4D-TBO procedure execution in an operational setting
Winds/4D-TBO - 7 06/24/15
• Parametric studies conducted on 3 aircraft/FMS combinations: – B737-700 with GE FMS (B737/GE)
• Full flight phase RTA speed control – B757-200 with Honeywell Pegasus FMS
• Current operational “Black Label” (B757/HW BL) Cruise-only RTA speed control
• Research prototype “Red Label v1” (B757/HW RL) Full flight phase RTA speed control User-adjustable “RTA tolerance setting” Calculation and display of ETA min/max User-adjustable RTA speed limits
Lincoln/MITRE FMS Simulations
Allowed assessment of performance of operational & prototype FMSs in controlled environments
Winds/4D-TBO - 8 06/24/15
Wind Information Analysis Framework
Element Independent Variable Values Tested Number of
Wind forecast error level and automation capability impact RTA performance
Winds/4D-TBO - 10 06/24/15
Avionics Control and Display Unit
(CDU)
Mode Control Panel
(MCP) Flight Control Computer
(A/P)
Auto Throttle Computer
(A/T)
Air Data Computer
(ADC)
Inertial Reference Computer (ADIRS)
Fuel Quantity/Flow
Computer (FQPU)
GPS
Digital Clock
Thrust Management
Computer (TMC)
FMC Discrete
Pins
FMS
Pilot
Airline ATC
• Can execute 20+ instances in parallel
Lincoln FMSim Implementation
Honeywell Pegasus
FMS
= Lincoln = Honeywell
Lincoln Virtual MCDU
Allows assessment of operational & enhanced FMSs in controlled environments & flexible simulation platform
CDU
Honeywell Pegasus
MCDU
Winds/4D-TBO - 11 06/24/15
• More robust FMS simulation capability enabled validation of Lincoln/MITRE results & expanded scope based on those results
• Key Lincoln/MITRE results and consequent research questions framed as specific hypotheses to be tested using LL FMSim: 1) Increased magnitude wind forecast error causes greater magnitude
RTA time error. 2) Aircraft/FMS types that do not maintain closed-loop control until the
RTA fix location have greater magnitude RTA time error as compared to systems that do.
3) Flights at lower cruise levels are more tolerant of wind forecast errors compared to flights at higher cruise levels.
4) Wind forecast errors closer to the RTA fix cause greater magnitude RTA time error.
• Assess RMS vector error (RMSVE) performance of each model at relevant forecast look-ahead times – 6+ hours: long range flight planning – 3-6 hours: short range flight planning – 1-2 hours: in-flight wind updates
• Model forecast performance analyzed for 10-month period (Nov 2013 – Aug 2014) and for four regions (SFO, PHX, ORD, EWR)
• Three forms of “truth” data considered – HRRR 0-hr analysis winds – Radiosonde observations (RAOB) – Aircraft met reports (AMDAR)
Wind Model Performance Assessment Approach
RAOB launch
3 RAOB sites
6 RAOB sites
5 RAOB sites
2 launches/site/day
3 RAOB sites
Winds/4D-TBO - 19 06/24/15
• Errors shown are averaged across all times, altitudes and regions
Wind Forecast Model Average Performance
On average, higher resolution forecast models have significantly better accuracy at <4 hr lookahead times, but similar performance to coarser models at >6 hr lookahead times
Winds/4D-TBO - 20 06/24/15
• Errors increase with forecast look-ahead time
• Long-tailed error distributions – Errors at any one time
may be significantly larger than the averages
• Large errors may persist for hours or days (see next slide)
Wind Forecast RMS Error Distributions for Different Look-Ahead Times
All forecast models have significant performance variability over time
Winds/4D-TBO - 21 06/24/15
Temporal Persistence of Large Wind Forecast Errors
6-month means
• Example shows persistent large (> 10 knots) 3-hour forecast errors during Feb 12-13, 2014 – Can we predict
when poor forecast wind model performance is anticipated?
Different forecast models often have similar performance trends, but not always
Winds/4D-TBO - 22 06/24/15
Case Study: Establishing Wind Information Needs and Associated ConOps/Datalink Needs to Support
a Given Level of Required 4D-TBO Performance
95%
RTA
Com
plia
nce
(sec
s)
Wind forecasterrorFMS RTA Capability/Tolerance
A-FMS=GE and HW RL FMS with full flight RTA controlB-FMS= HW BL FMS with
cruise RTA control only
1. Define scenarios of interest
2. Identify performance trade-space
3. Select target performance level
4. Do feasible combinations of performance drivers meet target level of performance?
Yes (wind error limit)
No
5. Do feasiblecombinations of wind
forecast model and look-ahead time meet error
limit?
Yes
No
Identified need for enhanced
automation and/or wind model
“or”
6. Define procedure/ConOps/datalink needs to get required wind info accuracy to aircraft
4D-TBO from cruise at FL290-390 to meter fix at 12,000 ft
±10 secs95% of time
(slice through
trade-spaceat 20 secs)
1) Any combination with 5 kts RMS wind error2) A-FMS/Tol 6 only with 15 kts RMS wind error3) No FMS/operation with 25 kts RMS wind error
Wind information neededto support any studied
aircraft/FMS combination
On average:GFS: cannot support 5 kts RMSE
RAP: <2.1 hrs lookaheadHRRR: <3.0 hrs lookahead
Winds/4D-TBO - 23 06/24/15
• Wind info quality impacts 4D-TBO procedure performance
• Analysis framework developed/exercised to explore relationships – Examples of what wind info & update rate meet target performance to
inform ConOps development and supporting technology needs – Limited set of Wind, ATC Scenarios and Aircraft/FMS types explored
• Findings informing range of stakeholders needs – e.g., RTCA Special Committees
• Next steps – Expanding Wind, ATC Scenarios and Aircraft/FMS types studied – Assessing near-term future FMS enhancements (10 altitude levels) – Predictability of wind errors in operationally-relevant time horizons