1. Capacity Enhancements in IMC for Airports with Converging Configurations with Knowledge of Aircraft’s Expected Final Approach Speeds: A Case Study Dr. Anand D. Mundra, Carrie L. P. Bodoh, David A. Domino, Ahmed El-Sahragty, John R. Helleberg and Arthur P. Smith © The MITRE Corporation This is the copyright work of The MITRE Corporation and was produced for the U.S. Government under Contract Number DTFA01-01-C-00001 and is subject to Federal Aviation Administration Acquisition Management System Clause 3.5-13, Rights in Data-General, Alt. III and Alt. IV (Oct. 1996). No other use other than that granted to the U.S. Government, or to those acting on behalf of the U.S. Government, under that Clause is authorized without the express written permission of The MITRE Corporation. For further information, please contact The MITRE Corporation, Contracts Office, 7515 Colshire Drive, McLean, VA 22102, (703) 883-6000 Fifth USA/EUROPE Seminar on ATM R&D 26 June 2003

2. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 2 Introduction Background Dependent Converging Instrument Approaches (DCIA) and the Converging Runway Display Aid (CRDA) Proposed modification of DCIA with knowledge of final approach target speed: Dynamic CRDA KORD application example and benefits Implementation issues and practical considerations Conclusions

3. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 3 Background: KORD Operations The Chicago O’Hare Airport (KORD) can support an arrival rate greater than 100 aircraft per hour in visual conditions. This rate is available when simultaneous arrivals on three runways (parallel and converging) are possible, a configuration currently restricted to good VMC weather. During IMC operations the third, converging runway is lost, reducing the arrival rate to about 70 per hour. Delay effects can propagate across the United States National Airspace System (NAS). 14L 14R 32R 04L 09L 27R 27L 09R 32L 04R 22L 22R KORD Runway Configuration

4. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 4 G2 Dependent Converging Instrument Approaches (DCIA) under IMC are authorized when supported by the Converging Runway Display Aid (CRDA). CRDA displays “ghost” target on final approach path of the other runway at the desired stagger distance. If both aircraft execute missed approach, stagger distance = a- b will guarantee separation at P, the intersection of the missed approach paths. This is a function of the distance from the respective missed approach points to the intersection of the runway centerlines, and the assumed speeds of the aircraft in this application. DCIA procedure has been used in the United States since 1992. Dependent Converging Instrument Approaches: A Basis for Capacity Enhancement

5. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 5 Dynamic CRDA: Basic Concept When distances from threshold to intersection are very long, (e.g., for long runways), the stagger values required by DCIA are too large to provide any capacity benefit In this paper we propose a change to the DCIA procedure in which stagger values would be based on planned final approach target speeds, instead of the “worst case” assumed speeds in the DCIA procedure. All other “worst case” parameters would be applied, and the same separation at the point of intersection (1 nm) would be provided. Fast time analysis suggests that significant improvement in arrival rate in IMC may be possible using DCIA based on planned approach speeds.

6. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 6 Effect of Approach Speeds on Required Stagger For a pair of converging runways of specific configuration, the approach speeds determine the required stagger. For this runway pair (32L/27R) worst case assumptions require more than 3 miles stagger, therefore little or no benefit. Knowledge of final approach target speed can reduce the required stagger, restoring benefits Stagger values will be determined for each participating arrival pair. Stagger surface: 32L leading 27R

7. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 7 Potential KORD Arrival Rates with Dynamic CRDA Arrival Rate Potential : Chicago O’Hare “Plan A” (32L, 27R, 27L)

8. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 8 Dynamic CRDA and Approach speeds Controllers need “ghost targets” displayed on the affected final approach to “set up” their traffic at least 10 to 15 mi before landing. Terminal radar automation system would require the estimated approach speed at least 15 minutes before landing so that the ghosts will be positioned properly.

9. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 9 Dynamic CRDA Operations Concept Stagger values will vary from pair to pair, based on planned approach speed. Note: Once established, stagger value remains constant. Pilots will confirm planned approach speed with approach control. Speed confirmation should occur as late as possible to minimize the likelihood of further adjustment. Controllers accept or reject planned speed with a single keystroke. –If planned speed is not within acceptable accuracy limits “standard” stagger values from the current DCIA order will be applied. Similarly, non-participants will also generate ghosts with the stagger values defined in the current order. Note: Not to scale

10. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 10 KORD “Plan A” Arrival Configuration with Dynamic CRDA, Triple Runway AC1 AC2 AC3 AC4 AC6AC5 1G 2G 14L 14R 32R 04L 09L 27R 27L 09R 32L 04R 22L 22R

11. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 11 Estimating Final Approach Speed What is the most effective means of generating the estimated approach speed? –Can approach speed be predicted with sufficient accuracy from ground based information via the Airline Operations Center (AOC)? –Will pilots be required to provide planned speed? Regardless of source, how accurate is the prediction? A/C Type Landing. Weight Flap Wind Planned Speed Actual Speed Pilot Judgement FTE V ref Speed Approach Speed Factors Airbus Automation Flt Ops Policy

12. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 12 Accuracy of Planned Approach Speed: Pilot Survey Over 500 pilots responded to an online questionnaire concerning their approach speed planning, procedures and management. Questions included –Identification of factors considered in approach speed planning, including company guidance on adjusting speed to account for surface wind conditions. –Estimate of approach speed accuracy –Frequency of planned speed modification after the initial determination. –Willingness to provide an estimated approach speed. The respondents represented more than 30 airlines 25 aircraft types.

13. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 13 Pilot Survey: Selected Results Approach speed accuracy –92 percent within +10 knots faster and no less than 5 knots slower than the speed briefed during the initial approach briefing. Frequency of planned speed adjustments after contacting Approach Control –41 percent indicated that they had modified their planned approach speed after contacting approach control. Procedure must accommodate speed adjustments, determine that their magnitude does not have a significant impact, or exclude aircraft whose planned speed has changed by a significant amount. Of course, actual data using real predictions by pilots and AOC will be required to validate that predicted speeds can be accurate and reliable enough to yield benefits.

14. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 14 Delivering the Planned Approach Speed: Datalink Options Automatic Dependent Surveillance-Broadcast (ADS-B): –MOPS has provision for threshold speed message. –However, in the near to mid term, not many aircraft may be equipped. US Controller Pilot Datalink Communication (CPDLC): –Build 1 has no provision for planned final approach speed message. Future builds could be designed to include this capability, but near term development plans are on hold. Current data link systems e.g., Automatic Communication Addressing and Reporting System (ACARS): –Possible near term candidate through the AOC, if availability/reliability/integrity issues can be addressed. –At least one carrier is assisting with an evaluation of this option.

15. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 15 Speed Uncertainty and Precision Affect Arrival Rate

16. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 16 Speed Uncertainty and Level of Participation Affect Arrival Rate KORD Plan A Arrival Rates: Effect of Speed Uncertainty and Participation Rate,

17. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 17 Operational Evolution Based on VMC applications of CRDA 14L 14R 32R 04L 09L 27R 27L 09R 32L 04R 22L 22R Potential near-term applications of CRDA –Elimination of Land and Hold Short Operations (LAHSO) in Plan W, (27L, 27R, 22R) –Restoration of Plan B (14L, 14R, 22R) which was made less useful by the replacement of turboprop aircraft with regional jets. Frees 22L for use as dedicated departure runway. Helps develop a controller experience base with CRDA in VMC applications.

18. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 18 Future Work Expand data collection to establish the predictive accuracy of planned approach speed. Continue to work the issues related to use of ACARS as a near term method of delivering speed prediction data to the ARTS automation. Continue exploration of near term applications of Classic CRDA including: –Tower issues and tower/approach coordination; additional human-in-the-loop simulations are planned. –Additional fast time analysis of potential benefits.

19. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 19 Conclusions Significant capacity gains may be possible by enhancing the Dependent Converging Instrument Approach procedures using Dynamic CRDA. In IMC about 10 extra arrivals per hour may be possible at KORD, if expected final approach speeds can be determined to within about 10 knots, and if at least 80 percent of aircraft participate. Pilot survey results suggest that the required prediction accuracy may be possible, and work is underway to validate that possibility. A mechanism for providing the required speed prediction to terminal automation has been identified Application of Classic CRDA may also provide near term benefits, and will serve to provide a necessary base of controller experience for the evolution to Dynamic CRDA.

20. 6/16/03 © 2003 The MITRE Corporation. All Rights Reserved. 20 Acknowledgments Present and past Chicago TRACON controllers provided valuable input and insight: –Doug Fralick, Mike Egan, Julie Mirfield, and Don Porter. MITRE colleagues also made significant contributions regarding the datalink options: –Steve Giles, Frank Buck, John Mayo and Ed Hahn