1. Estimating the En route Efficiency Benefits Pool Dan Howell, Michael Bennett, James Bonn, CNA Corporation Dave Knorr, FAA AOZ-40 June 23, 2003

2. 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

3. CNA Programs expected to contribute to delay and flight efficiency savings Program/CapabilityEn RouteTerminalSurfaceProgram/CapabilityEn RouteTerminalSurface ADS-B XXX Medium Intensity Airport Weather System (MIAWS) X ASDE-X, ASDE-3 X Power Systems XX CPDLC X Precision Runway Monitor (PRM) X CRCT XX Additional RNAV Routes XX En Route Communications Gateway (ECG) X Radio Frequency Interference (RFI) XX ERAM XX Required Navigation Procedures (RNP) XXX Departure Sequencing Program (DSP) XX Terminal Radars (ASR-9 SLEP, TDWR) XX DRVSM X Traffic Flow Management (TFM) XXX Integrated Terminal Weather System (ITWS) X TMA XX Local Area Augmentation System (LAAS) X URET X NEXCOM XX Wide Area Augmentation System (WAAS) X NAS Infrastructure Management System (NIMS) XXX Winds Aloft Prediction in Non- convective weather X Chart from FAA ASD-400 presentation

4. CNA Sources of En route Inefficiency Route Structure Conflict Avoidance Sector Capacity Terminal Congestion Severe Weather Example of En route inefficiency due to Terminal Congestion Route Structure Conflict Avoidance Terminal Congestion Sector Capacity Severe Weather ModelInefficiency Source

5. CNA Inefficiency and excess distance Actual or Planned track Great Circle path In order to study inefficiency we must refine definition to examine benefits. 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

6. CNA Excess distance and traffic load Average excess distance per flight (nmi) Percent of maximum center traffic 0 10 020406080100 Opportunity Regime Route Structure Regime Congestion Regime More Directs (URET,PARR,D2) More Efficient Routes (RNP, airspace redesign) More Capacity or less conflicts (RVSM, URET, Data link)

7. CNA Excess distance vs. traffic load in different centers 0 5 10 15 20 0 406080100 Percent of maximum center traffic Average excess distance per flight (n. mi.) ZOA ZAB ZOA - has higher traffic levels - handles a higher proportion of arrivals and departures than ZAB. More complex route structure Greater susceptibility to capacity-related effects

8. CNA National excess distance benefits pool ~29 % of total excess distance occurs in the en route environment Method 1Method 2 MetricActualPlanActualPlan Mean (nmi)28.522.09.310.0 Sum (nmi)1,296,5561,141,967369,968427,803 % flight7.76.92.43.1 1 Actual or Planned track Great Circle path. 50 nmi. 2 ~Entire flight En route portion After removing foreign and round-robin flights, a good weather day of ETMS track data contains ~50,000 flights. How much of this pool is recoverable? Calculated excess distance using two methods

9. 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 More en route potential conflicts arise from aircraft on the current air route structure than would be the case for direct routings. Flight Plan RoutingDirect Routing Total Conflicts10,1578008 Average conflicts per plane0.470.37 # of planes with conflicts12,01210,412 % of planes with conflicts28.024.3 Average conflicts per conflicted plane1.691.54

10. CNA Estimating conflict cost Potential Conflict Original Flight Path Revised Flight Path  Conflict cost depends on: 1. Conflict radius 2. Conflict angle 3. Speeds 4. Resolution start 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.

11. 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.

12. CNA Conflict Cost Results Used conflict angle distribution from FACET detection analysis Using minimumUsing buffered Original excess distance pool369,968 nmi Mean excess distance per conflict1.4 nmi3.63 nmi Total excess distance for conflicts22,407 nmi58,149 nmi New excess distance pool347,561 nmi311,819 % of original pool diminished by conflicts 616 Translating distance into annual dollars ( $ = (distance/speed)*ADOC * (343 eff.days)) we find and annual savings for new pool of $699M - $786M

13. CNA Comparison with other studies *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. Study Annual Benefit (dollars)* Number of eligible flights per day Daily Benefit per Eligible Flight (min)** FAA AOZ study (2002)699-786M39,7531.32 – 1.49 Delta (1996)42M – 92M2,000 (Delta Fleet)1.58 – 3.46 (2) NASA D2 study (1996)107 – 279M5399 - 94881.49 – 2.21 (2.8) MITRE ETMS (2000)~700M29,0451.81 MITRE TMAC (2000)620M31,0001.50 Seagull Technology (1998)557 – 652M40,437 – 50,1570.98 – 1.03 FAA ASD S. Region (2002) – time savings for Direct/Wind optimized 2692 (S. Region, over 750 nmi) (3.8 in 2005) MITRE Flying times (2003) – using optimum time over 30 days 7300 (regional pairs)(5.6)

14. 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.