Phase I Submission Name of Program: Equivalent Lateral Spacing Operation (ELSO) Name of Program Leader: Dr. Ralf Mayer Phone Number: 703-983-2755 Email: rmayer@mitre.org Postage Address: The MITRE Corporation, 7515 Colshire Drive, M/S N390, McLean, VA 22102 Name of Customer Representative: Bruce DeCleene, AFS-400 Division Manager Phone Number: 202-385-4586 Email: bruce.decleene@faa.gov Nomination Point of Contact: Dr. Tom Becher The MITRE Corporation 703-983-5590 tbecher@mitre.org Phase 1 Bio for Program Leader Dr. Ralf Mayer received his Ph.D. degree in experimental physics from Purdue University and has over 10 years of research experience in physics and aviation. Dr. Mayer holds commercial pilot and flight instructor certificates and served on the staff of Purdue University s Aviation Technology Department before joining The MITRE Corporation s Center for Advanced Aviation System Development (CAASD) in 2001, where he worked on capacity/delay/fuel burn benefit evaluations of airspace designs and procedure implementations. While at MITRE, he has contributed to technical books, spoken and chaired technical sessions at multiple conferences such as Integrated Communications Navigation and Surveillance (ICNS) and Digital Avionics Systems Conference (DASC), and written over 31 aviation-related papers. Dr. Mayer is a member of the American Physical Society (APS) and Eurocontrol s Base of Aircraft Data (BADA) User s Group and reviewer of the IEEE Intelligent Transportation Systems Transactions and Magazine journal. Ralf formed a diverse technical team to investigate some promising research ideas for reducing separation standards based on the improved navigation performance of area navigation (RNAV) equipped aircraft. Over his career at MITRE, Ralf has developed a deep understanding of complex operational changes at many of the airports in the National Airspace System (NAS) such as Chicago O Hare International Airport (ORD), Dallas Ft.-Worth International Airport (DFW), and Atlanta Hartsfield-Jackson International Airport (ATL) which is foundational. Under his technical guidance, he and his team converged on an operational concept for reduced divergence that was validated through the team s business relationships at ATL.
As a simulation and modeling expert, he exhibits technical independence, and his years of expertise enabled him to create a data analytic and engineering foundation for the proposed reduced divergence separation standard. With the solid foundation in place, Ralf and his team were able to positively influence the FAA decision to approve Equivalent Lateral Spacing Operation (ELSO) for operational use at ATL. Ralf and his team took the initiative to spend time at ATL when the ELSO operation was turned on to directly observe the operation and obtain feedback from the controllers and pilots. He also put into place a post-operational data collection effort that would provide quantitative insight into the benefits of the operational change. The post- operational analysis was valuable for demonstrating to the controllers, airlines, and FAA senior leadership that ELSO was delivering on the proposed benefits. These results allowed MITRE and Ralf s team to engage in a multi-level strategy with the FAA to quickly move forward on implementing ELSO as a national standard which is underway. Ralf s technical leadership has positioned the FAA to apply this concept of reduced divergence to the transition from the terminal to the en route, creating more departure gates and reducing distance flown. The concept can also be applied to single runway operations, enabling more departure capacity while still meeting airspace constraint. Ralf and his team have taken full ownership of this work, which includes concept development, engineering and operational analysis, benefits, and site applications. This was complemented with targeted messaging to engineers, project managers, and business leaders/decision makers within MITRE and the FAA. In partnership with the Federal Aviation Administration (FAA), The MITRE Corporation s Center for Advanced Aviation System Development (CAASD) has been developing concepts for new separation standards to improve the efficiency of the U.S. National Airspace System (NAS). In 2010, MITRE engineers and operational experts Ralf Mayer, Dennis Zondervan, Al Herndon, and Tyler Smith developed this new standard to provide short-term, easy-to-implement solutions for conducting departure operations more efficiently in constrained airspace that surrounds the nation s busiest airports. The engineers grounded their innovative work by staying closely connected to the operational staff at Atlanta s Hartsfield-Jackson International (ATL) the world s busiest airport. MITRE management provided the resources and environment to support the creativity required to put the concept on a solid analytic foundation and anticipate addressing issues and questions related to safety. This work resulted in formulation of the concept of the Equivalent Lateral Spacing Operation, or the ELSO standard. To obtain broader feedback on the concept and the technical approach, the team published a technical research paper on ELSO, which Dr. Mayer presented at the 2011 USA/Europe Air Traffic Management Research and Development Seminar in Berlin. This international forum meets approximately every 18 months and is selective in choosing topics.
ELSO capitalizes on advanced area navigation (RNAV) equipment already installed and used in most aircraft and, where possible, the layout of an airport s runways. Application of the ELSO concept redefines the minimum angle that is required between departure routes and enables air traffic controllers to clear aircraft for takeoff in a more efficient manner. When the current 15-degree divergence radar separation standard was developed and adopted, Performance-Based Navigation (PBN s) key characteristics that enable precise and repeatable operations did not exist. With the PBN concept and resulting operational changes now a reality, it was time to also evolve applicable separation standards. Taking into consideration specific runway layout geometries and the precision with which today s aircraft navigate along advanced RNAV routes, the ELSO concept allows reduction of the divergence angle by about one half of the existing standard (to 5 to 10 degrees) if departures take off from parallel runways, and by about one third (to 10 degrees) if the aircraft are cleared to take off on the same runway. These airspace-saving reductions enabled Atlanta to add a fourth diverging departure route when aircraft are departing in both east and west runway configurations. Now, aircraft can be cleared for takeoff more efficiently than before, thus increasing the departure capacity of the airport by approximately 10 percent without any costly infrastructure changes. The idea for the new standard concept came from prior MITRE studies that investigated operational benefits associated with diverging RNAV departure operations. These operations became possible in 2005 when RNAV Standard Instrument Departure procedures were first introduced at several of the nation s busiest airports. Implementations of these procedures are part of the FAA s strategy to transition from a conventional ground-based navigation concept to a PBN concept that more heavily relies on the U.S. Global Positioning System of satellites for aircraft navigation. Unlike conventional departures that require successive issuance of air traffic control instructions to change the direction that aircraft are heading, PBN departures proceed along established routes. PBN s precision and repeatability have fundamentally changed aircraft operations in the terminal area. However, the air traffic control standards that apply when separating these aircraft have not. MITRE was seeking cost effective and high impact methods to take advantage of PBN s navigational performance. Three initial goals were set: First, develop a separation standard that enables operational improvements for the Next Generation Air Transportation System (NextGen), while maintaining an equivalent level of safety. Second, devise a methodology that ensures that operational benefits can be realized in the near-term. Third, develop application requirements for the new standard that facilitate the needed regulatory review and approval process. If all of these goals were met, the chances of success would be much higher. Why focus on departure routes rather than arrivals? Departure routes at metropolitan airports are often constrained by noise sensitive areas. Reducing divergence requirements may permit
additional departures routes within designated departure flight corridors, increasing airport departure rates, and reducing delays. A reduced divergence separation standard would provide more flexibility, allowing Air Traffic to meet constraints, and provide more departure capacity without building new runways. The benefits of ELSO are: Increased departure efficiency Increased departure capacity Increased throughput especially during peak demand periods Reduced departure delay (taxi-out times) Reduced fuel burn and emissions Additional departure procedure design options that improve the ability to address terrain/obstacle and noise sensitivity constraints. The development and application of the ELSO concept ensured that near-term benefits could be realized from evolving the divergence standard. Application of the ELSO concept to diverging departure operations offers reduced divergence angles while maintaining the lateral spacing between the departure paths that is equivalent to the spacing observed in conventional diverging departure operations at minimum requirements of the current standard. By maintaining the current lateral separation standard, this reduces the hazards that need to be addressed for safety such as avoiding wake vortices. Reducing the hazards that need to be considered reduces the timeline and cost for implementation. Over the past decade, the terminal RNAV capability has been quickly adopted by the aviation industry and is now widely used. This ELSO application leverages the RNAV capability of today s fleet of aircraft. From 2002 through 2011, RNAV equipage of key operators in the NAS has risen from just over 70 percent RNAV capability to 98 percent RNAV capability. Thus, applying the ELSO concept to RNAV operations ensured wide applicability of the new standard and maximized its benefit potential. One of the stated NextGen goals is to use RNAV and Required Navigation Performance (RNP) to enable more efficient aircraft trajectories and increase airspace efficiency and capacity. ELSO is a prime example of NextGen at work in the NAS. The MITRE team s third goal of developing application requirements that are based on technical and engineering analysis of operational data aimed to put the standard on an objective analytic footing and facilitate the regulatory review and approval process. FAA separation standards are not easily modified. ELSO changes separation standards for diverging operations that have been in place for over 50 years. The team worked closely with FAA organizations to support the decisions required for the approval of the standard for operational evaluation at Atlanta. Operations in Atlanta have such a high percentage of PBN aircraft that it makes for a perfect location for operational evaluation of the ELSO concept.
The ELSO standard concept was reviewed by the FAA s PBN Policy and Support Group, the Flight Technologies and Procedures Division, and the Office of Safety. Concurrence on the technical and operational analysis was obtained in May 2011. An operational waiver was issued in August 2011 that authorized Atlanta to implement a new set of ELSO-based procedures. Following its implementation, operational evaluations of the NextGen RNAV ELSO procedures, as they are now called, began October 20, 2011 at Atlanta. ELSO benefits have been demonstrated at Atlanta since operations have been conducted under a waiver starting in October 2011. The annual departure delay benefits are estimated at $20 million dollars annually. Feedback has been obtained directly from the ATL facility directly and from Delta Airlines. Both parties view ELSO as being a very positive change and exceeding anticipated benefits. Post-implementation analysis has confirmed the benefits stated above. ELSO-based standards offer a suite of additional procedure-design options not currently available to better accommodate airspace and environmental constraints and to increase the efficiency of departure operations. ELSO is an excellent example of transforming the NAS with PBN. It allows air traffic control to fundamentally change the operation by increasing the use of available airspace. ELSO is also environmentally friendly. The potential exists to move departure paths over more environmentally desirable areas due to the added flexibility it provides procedure designers. Meeting the three established objectives paid off. As a next step, the team has been tasked to support Atlanta s operational evaluations and inform the FAA on its path to enabling NASwide application of ELSO-based separation standards. MITRE actively engaged the FAA at all levels to make them aware of the low-cost, high-value proposition associated with ELSO. MITRE conducted a benefits study to examine major airports in the NAS to assess ELSO as providing potential benefit. This study showed that there were many other airports that would benefit from ELSO in addition to ATL. The research also has applicability for the terminal-to-en route transition airspace where credit for improved PBN navigation performance can again reduce the divergence needed called the Standard for Established-on-Departure Operations (EDO) concept. The EDO and ELSO standards were applied to the RNAV Standard Instrument Departure (SID) structure at Atlanta to illustrate implementation examples and estimate potential benefits. For ATL alone, conservative estimates show a potential additional annual monetary benefit of approximately $1.9 million per year for EDO. One departure flow was found to contribute over $23 per departure to the benefit. Considering all departures, the total benefit corresponds to an average cost reduction of nearly $5.25 per flight. When applied conjointly, the EDO and ELSO standards offer a suite of additional procedure design options not currently available to better accommodate airspace
constraints and to increase the efficiency of departure operations transitioning from terminal to en route control.