Evaluation of Strategic and Tactical Runway Balancing*

Transcription

1 Evaluation of Strategic and Tactical Runway Balancing* Adan Vela, Lanie Sandberg & Tom Reynolds June th USA/Europe Air Traffic Management Research and Development Seminar (ATM2015) *This work was sponsored by the Federal Aviation Administration (FAA) under Air Force Contract FA C Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the United States Government

2 Current Shortfall Tower controllers lack decision-support tools (DST) to help with strategic and tactical runway assignments to balance runway demand; imbalanced runway demand may result in unnecessary departure delays. Proposed Terminal Flight Data Manager (TFDM) DSTs aim to forecast individual runway departure demand over relevant time horizons and increase awareness of alternative operating configurations to improve operations. Current Demand: 10 8 Future Demand: Strategic &Tactical Runway Assignment refers to how aircraft are assigned to departure runways for a given runway configuration; they are distinct from runway configuration planning. Runway Balancing 2

3 Departure Runway Assignment BLECO GRABE LOWGN AKUNA Strategic Creating runway assignment rules (keeping the runway configuration static) Goal: Maximize runway utilization, prevent runway starvation, balance runway waittimes Tactical Assigning aircraft to alternative departure runways (at push back) Goal: Advance expected take-off times; utilize open slots, shorter taxi times Runway Balancing 3

4 Strategic Runway Assignment: Current Operations Daily patterns and standard operation procedures guide runway assignment rules Air traffic control adjusts runway assignment rules in response to current/near-term demand (e.g. remap departure procedure to a different runway) BLECO GRABE LOWGN AKUNA BLECO GRABE LOWGN AKUNA Runway Balancing 4

5 Strategic Runway Balancing: Proposed TFDM Capability Decision-support tool forecasts demand at each runway and over each departure fix (~30 minutes) Air traffic control uses information to craft optimal runway assignment rules Once rules are set, system automatically reassigns aircraft departure runways and recalculates demand BLECO GRABE LOWGN AKUNA BLECO GRABE LOWGN AKUNA Departure Split 36L 36R East/West East+G/West East/West+B Note: The Airport Resource Management Tool (ARMT), a strategic runway balancing DST, is currently in use at ATL. Runway Balancing 5

6 Tactical Runway Assignment: Current Operations Pilots request alternative runway assignment Air traffic control verifies operational suitability, and accordingly, provides estimated take-off time? GRABE Runway Balancing 6

7 Tactical Runway Balancing: Proposed TFDM Capability Candidate aircraft are automatically identified for alternative runway assignment (based on departure procedure) System verifies alternative runway assignment advances expected take-off time without impeding other aircraft Proactively proposes new assignments to air traffic control? GRABE Runway Balancing 7

8 Research Goals DFW, LAX, MCO ( ) Calculate the potential current and future-year delay reductions that are directly attributed to strategic runway balancing through a departure fix-torunway mapping tool that seeks to balance departure demand across runways. Current-day airport geometry and operations Calculate the potential current and future-year delay reductions that are directly attributed to tactical runway balancing through assigning aircraft to alternative departure runways. Common Characteristics: Parallel departure runways Differing Characteristics: Number of departures, demand across filed departure procedures, taxi times Runway Balancing 8

9 Benefits Analysis Methodology Simulate airport operations with varying strategic and tactic runway balancing Track taxi-time and runway wait-time Calculate average daily taxitime in movement-area time. (Scale annually) Input: Aircraft departure schedule (time, departure procedure, aircraft type, etc.) at an airport. Twelve representative days for each year (2010, 2015, 2020, 2025, and 2030). Operational Settings (Strategic & Tactical) Traditional Operations Strategic Balancing Fully Balanced No Tactical Balancing Tactical Balancing Runway Balancing 9

10 Generic Airport Operations Model Departure Schedule Pushback Strategic Balancing Strategic RWY Assignment Tactical Balancing Tactical RWY Assignment Taxi to RWY RWY Service Queue Sequencing Runway Configuration Note: Each controller and process has access to relevant airport state information (e.g. queue lengths, future demand) Legend Model Input Arrival Schedule Model Output Queue, Process, Or Controller Model System States Cost Analysis Runway Balancing 10

11 Simulation Framework Discrete-event model Pushback Runway assignment Arrive at spot Release from spot (taxi to RWY) Arrive at RWY queue (wait in RWY queue) Take-off Arrival At each event time, the state of the airport is updated. Airport States Number of taxiing aircraft Number of aircraft at RWY Runway configuration Etc. Any relevant information that affects taxi times, queue wait times, or other stochastic or decision processes. Simulation does not explicitly model phenomena between events (e.g. intersecting aircraft while taxiing) Runway Balancing 11

12 Modeled Control Elements Strategic Runway Assignment Today s departure+airline mapping [Traditional Runway Mapping] Dynamic load-balancing mapping (TFDM) [Strategic Runway Balancing] Any departure to any runway (Benefit pool) [Fully Flexible] Tactical Runway Assignment No tactical runway assignment (only strategic runway assignment) Earliest available take-off slot (TFDM) [OpenSlot] Earliest available take-off (Alternative) [GreedySlot] Runway Balancing 12

13 Strategic Runway Assignment: Current Operations Baseline Mapping Today s nominal operation based only on aircraft departure procedure Traditional Runway Mapping Today s nominal operation taking into account both departure procedure & airline L 9R L 9R UAL % 40% 60% 40% Runway Balancing 13

14 Strategic Runway Assignment: Strategic Runway Balancing (TFDM) Starts from baseline mapping Maps departures to runways to balance runway demand Regular updates to mapping [30 min] Considers queue at runway + scheduled demand L 9R % 40% Changes require that imbalance reduces by 5 aircraft Able to account for asymmetrical departure rates L 9R % 47% Runway Balancing 14

15 Tactical Runway Balancing (TFDM) Flexible Departure groups Identify overloaded runway Select departure groups at boundaries that maximize number of flexible aircraft (taken from overloaded runway) 5 AC 2 1 9L 9R AC AC 9L 9R AC 2 in queue 20 at gate 4 in queue 15 at gate 9 AC 2 in queue 15 at gate 4 in queue 15 at gate Runway Balancing 15

16 Tactical Runway Balancing: OpenSlot Aircraft default to assigned runways If aircraft is departing to a flexible departure it is eligible for changing runways An eligible aircraft can only change runways if it advances the estimated take-off time does not delay other aircraft (there must be a free slot) 9L Flexible Aircraft Fixed Aircraft (9L) 9R Fixed Aircraft (9R) Expected Take-Off Time Runway Balancing 16

17 Tactical Runway Balancing: GreedySlot Aircraft default to assigned runways Flexible aircraft selects runway with earliest expected departure May delay other aircraft 9L 9R Flexible Aircraft Fixed Aircraft (9L) Fixed Aircraft (9R) Expected Take-Off Time Runway Balancing 17

18 Remaining Simulation Model Components Departure Schedule (Input) System-Wide Analyses Capability Tool (SWAC); a fast-time NAS simulator that forecasts airport demand. Simulation uses the SWAC output schedule as an input: Destination airport, aircraft type, airline, schedule & actual pushback, filed departure procedure Taxi Time Modeling Aircraft are assigned random spot locations based on airline and destination (domestic/international) Based on historical taxi times (from ASDE-X data), a random forest regression model assigns aircraft taxi times to their assigned departure runway Input: Spot location & Departure Runway Output: Taxi Time Runway Balancing 18

19 Remaining Simulation Model Components Departure Resequencing Used to increase departure throughput (not intended to constitute an operational improvement) Simple aircraft swapping (adjacent aircraft in queue) Aircraft are limited to at most one swap Runway Service Times Sequential departing aircraft are spaced to ensure separation and prevent wake turbulence hazards Spacing times are based on historical departure data (PASSUR) Spacing times for aircraft on different departure routes [seconds] (L/F = Leader/Follower) L/F Small Large 757 Heavy Small Large Heavy Spacing times for aircraft on the same departure route [seconds] (L/F = Leader/Follower) L/F Small Large 757 Heavy Small Large Heavy Runway Balancing 19

20 Dallas/Fort Worth Airport (DFW) Departure Configuration RWY Prediction Rate [Percent] (Departure Group) RWY Prediction Rate [Percent] (Departure Group + Airline) 17R-18L Static Baseline Mapping 6% 5% 4% 11% 5% % 1% L 17R 11% % 3% 1% 4% 44% 56% 7% 11% 10% 11%.75 miles Operations are well-balanced; easy to balance at the runways through strategic runway balancing Runway Balancing 20

21 Strategic Runway Assignment: Avg. Daily Movement-Time 1 min saving per aircraft 12 Day Avg. (SWAC) Little difference at 2010 traffic levels By 2030, Strategic runway balancing outperforms traditional runway assignments Strategic Runway Balancing L 17R Departure fix can be remapped to either runway Runway Balancing 21

22 Avg. Daily Reduction in Surface Delays [Hours] Tactical Runway Assignment: Reduction in Avg. Daily Movement-Time Strategic Runway Balancing (Baseline) Strategic Runway Balancing+OpenSlot Strategic Runway Balancing+GreedySlot Year OpenSlot: Less than 1% Reduction ~2 sec per aircraft (over all aircraft) (using approx. 10 of 110 candidate aircraft) GreedySlot: <1% Reduction ~5.4 sec per aircraft (over all aircraft) (using approx. 30 of 110 candidate aircraft). Strategic Runway Balancing At DFW, strategic runway balancing is able to balance runways successfully, leaving a smaller benefit pool for tactical runway balancing L 17R Runway Balancing 22

23 Aircraft Switching at DFW With an equal number of flexible aircraft departures, GreedySlot is able to reassign aircraft more often than OpenSlot OpenSlot rules limit runway switching Runway Balancing 23

24 Runway Balancing Benefits Reducing Total Surface Delays Airport Site # Days of VMC between hours of 8AM and 11PM for 2013 [ASPM] DFW 225 LAX 183 MCO 233 At high-traffic airports (DFW+LAX) using forecast tools to strategically balance departure demand across runways can substantially reduce total surface delays (DFW: 30K, LAX: 514K Hrs) At low-traffic airports (MCO) forecast tools do not provide delayreduction benefits over traditional operations (MCO: -35K Hrs) Note: Conservative estimate, excludes IMC days Runway Balancing 24

25 Runway Balancing Benefits Reducing Total Surface Delays Airport Site # Days of VMC between hours of 8AM and 11PM for 2013 [ASPM] DFW 225 LAX 183 MCO 233 OpenSlot provides limited benefit, especially when strategic runway balancing is able to balance demand. (MCO: 6.4K, DFW: 2.9K, LAX: 8.3K Hrs) GreedySlot demonstrates that there still remains potential delay savings to be had through tactical runway balancing (MCO: 13.6K, DFW: 5.6K, LAX: 52.2K Hrs) Note: Conservative estimate, excludes IMC days Runway Balancing 25

26 Orlando International Airport (MCO) Departure Configuration RWY Prediction Rate [Percent] (Departure Group) RWY Prediction Rate [Percent] (Departure Group + Airline) 17R-18L Static Baseline Mapping 1% 28% 1% ~0% 9 8 Runway Balancing 26 14% 1% 40% L 17R 7 6 4%.5% 34% 66% 4 5.5% 10% Makes operations more challenging to balance. Strong airline preferences 1.5 miles MCO departure demand is significantly less than at DFW and LAX

27 Los Angeles International Airport (LAX) Departure Configuration RWY Prediction Rate [Percent] (Departure Group) RWY Prediction Rate [Percent] (Departure Group + Airline) 24L-25R Static Baseline Mapping 11% 1 18% 18% 2 24L Long taxi dist. to alt. runway (up to 3 miles) 8% 3 25R 9 1% % 31% 4% 4% 1% 71% 29% Makes operations more challenging to balance LAX departure demand is ~2X MCO departure demand over Runway Balancing 27

28 Ongoing Work: Identifying Other High- Impact Airports Increasing Benefit Airports that will benefit from strategic and tactical runway balancing will have high traffic demand and unbalanced/uneven departure-demand across filed departure procedures. (Asymmetrical taxi times between runways also appears to be a relevant factor) Expected Benefits LAX: SEA, PHL, IAH, PHX (High impact) DFW: MSP, CLT, and ATL (Medium impact) MCO: DTW, SFO, SLC, MIA, LAS (Low impact) Runway Balancing 28

29 Runway Balancing 29 Questions?

30 Orlando International Airport (MCO) Departure Configuration RWY Prediction Rate [Percent] (Departure Group) RWY Prediction Rate [Percent] (Departure Group + Airline) 17R-18L Static Baseline Mapping 1% 28% 1% ~0% 9 8 Runway Balancing 30 14% 1% 40% L 17R 7 6 4%.5% 34% 66% 4 5.5% 10% Makes operations more challenging to balance. Strong airline preferences 1.5 miles MCO departure demand is significantly less than at DFW and LAX

31 MCO: Strategic Runway Balancing Strategic Runway Balancing L 17R Allows departure group 3 (40%) to be flexible for tactical runway balancing Runway Balancing 31

32 Strategic Runway Assignment: Avg. Daily Movement-Time (MCO) 12 Day Avg. (SWAC) Some distinction at 2010 traffic levels Traditional runway mapping out-performs strategic runway balancing Runway Balancing 32

33 Avg. Daily Reduction in Surface Delays [Hours] Tactical Runway Assignment: Reduction in Avg. Daily Movement-Time (MCO) Strategic Runway Balancing (Baseline) Strategic Runway Balancing+OpenSlot Strategic Runway Balancing+GreedySlot Traditional Year Strategic Runway Balancing L 11 17R Even with tactical runway balancing, strategic runway balancing does not outperform traditional runway assignment. Appears that ATC already performs runway balancing (preferred runway assignments). Runway Balancing 33

34 Aircraft Switching at MCO MCO has significantly more flexible aircraft departures than DFW More than 2X aircraft switch runways at MCO than DFW However, MCO Delay Reduction 2X DFW Delay Reduction Runway Balancing 34

35 Los Angeles International Airport (LAX) Departure Configuration RWY Prediction Rate [Percent] (Departure Group) RWY Prediction Rate [Percent] (Departure Group + Airline) 24L-25R Static Baseline Mapping 11% 1 18% 18% 2 24L Long taxi dist. to alt. runway (up to 3 miles) 8% 3 25R 9 1% % 31% 4% 4% 1% 71% 29% Makes operations more challenging to balance LAX departure demand is ~2X MCO departure demand over Runway Balancing 35

36 LAX: Strategic Runway Balancing L 25R Strategic runway balancing allows departure group 5 (31%) to be flexible Runway Balancing 36

37 Strategic Runway Assignment: Avg. Daily Movement-Time (MCO) 12 Day Avg. (SWAC) Little distinction at 2010 traffic levels Traditional runway mapping does not appear to be sustainable Strategic runway balancing almost equals the fully flexible mapping (benefit pool) Runway Balancing 37

38 Avg. Daily Reduction in Surface Delays [Hours] Tactical Runway Assignment: Reduction in Avg. Daily Movement-Time (LAX) Strategic Runway Balancing (Baseline) Strategic Runway Balancing+OpenSlot Strategic Runway Balancing+GreedySlot Fully Flexible L 25R Year Tactical runway balancing with GreedySlot is nearing the total benefit pool of the fully flexible case, while still being operationally feasible. Runway Balancing 38

39 Aircraft Switching at LAX Greatest number of flexible aircraft departures 2X aircraft switch runways at LAX than MCO LAX Delay Reduction >> 2X (MCO or DFW Delay Reduction) Percentage of aircraft reassigned runways decreases each year Runway Balancing 39