En Route Automation Modernization Research Articles

Achieving 100% availability

Fault tolerance is a key requirement for En Route Automation Modernization (ERAM), the FAA's system that manages En Route air traffic over the USA. A system failure could lead to hundreds of flights being delayed or cancelled. Using experience from earlier systems a set of techniques were built into ERAM at inception, including a hot standby copy of each executable and the latest state checkpointed in disk files. As the system matured through formal testing and operational experience at the first sites (2010 - 2015), the goal of 100% availability was not achieved so additional techniques were added. These included exception safety, runaway process protection, and proactive monitoring of the system to detect defects and often resolve them without the air traffic controllers being aware. With the implementation of these additional techniques the FAA has measured ERAM as 100% available from October 2016 at all 20 operational sites. Software fault tolerance techniques have been well documented [2]; this extended abstract describes the specific techniques that have led to ERAM achieving continuous 24x7 availability for 6 years.

Visual Search and Conflict Mitigation Strategies Used by Expert en Route Air Traffic Controllers

The role of the en route air traffic control specialist (ATCS) is vital to maintaining safety and efficiency within the National Airspace System (NAS). ATCSs must vigilantly scan the airspace under their control and adjacent airspaces using an En Route Automation Modernization (ERAM) radar display. The intent of this research is to provide an understanding of the expert controller visual search and aircraft conflict mitigation strategies that could be used as scaffolding methods during ATCS training. Interviews and experiments were conducted to elicit visual scanning and conflict mitigation strategies from the retired controllers who were employed as air traffic control instructors. The interview results were characterized and classified using various heuristics. In particular, representative visual scanpaths were identified, which accord with the interview results of the visual search strategies. The highlights of our findings include: (1) participants used systematic search patterns, such as circular, spiral, linear or quadrant-based, to extract operation-relevant information; (2) participants applied an information hierarchy when aircraft information was cognitively processed (altitude -> direction -> speed); (3) altitude or direction changes were generally preferred over speed changes when imminent potential conflicts were mitigated. Potential applications exist in the implementation of the findings into the training curriculum of candidates.

Challenges and lessons learned introducing an evolving open source technology into an established legacy Ada and C++ program

When the Federal Aviation Administration (FAA) launched the System Wide Information Management (SWIM) initiative, the FAA had the goal of using the same portable, open infrastructure across all participating systems in the National Airspace System (NAS). Around 2008 for SWIM Segment 1, the FAA chose Iona Software's Free/Open Source Software (FOSS) based bundle, which was known and supported under the Fuse brand. The FAA obtained the licenses used by programs, including EnRoute Automation Modernization (ERAM), through Iona, which was later acquired by Progress and RedHat.

Evaluation of NextGen Air Traffic Control Alarms and Alerts Using Cognitive Walkthrough Method

In the air traffic control domain, there are no clear distinctions in the definition of critical safety messages, such as alarms and alerts. We therefore created a categorization scheme to distinguish alarms from the alerts and applied it to NextGen air traffic control systems: Standard Terminal Automation Replacement System (STARS), En Route Automation Modernization (ERAM), and Data Communications. Controllers then evaluated the effectiveness of the alarms and alerts of these NextGen systems. We used Cognitive Walkthrough method with the “thinking aloud” procedure to collect their spontaneous and immediate evaluation. Based on these evaluations, we present recommendations for the future NextGen air traffic control alarm and alert design.

Predictive Weather Display in ATC: Implications for Research and Training

Two systems are central to the Next Generation Air Transportation System (NextGen) air traffic management program - Traffic Management Advisor (TMA) and En Route Automation Modernization (ERAM). One purpose of both systems is to reduce air traffic control (ATC) delay. The present study reports on an exploratory integration of convective weather, a major source of delay, into the ATC systems to allow early re-route around weather in order to reduce delay. Pseudo-controllers ran a series of simulation-based scenarios with screen capture and video collection to assess delay and safety performance. Results provide evidence that delay was reduced by early rerouting in response to convective weather predictions. Implications for training and research are discussed.

Experience report

The Ada language has been architected to provide a strong foundation for building software at the heart of safety critical, real-time, and long-maintained programs. The benefits of Ada in such environments have led to its use in a wide range of systems where correctness and predictability are critical. The current trend in our industry is to loosely tie systems together to share data that previously required manual re-entry, simply was not available, or worse could have been inconsistent between systems. This trend is resulting in a need to connect previously closed systems over in-house and external networks to perform that loose linkage. The FAA has embraced this technology and has been developing an architecture, code framework, and standards for sharing data across their entire spectrum of Air Traffic Control systems and consumers. The FAA's overall umbrella for this is termed SWIM (System Wide Information Management), and programs participating in the architecture are called "SWIM implementing programs". The ERAM (EnRoute Automation Modernization) program I work on and previously presented at SIG Ada 2009 is one of the first SWIM implementing programs. ERAM has recently entered the test phase of the first increment of SWIM functionality. ERAM SWIM faced many of the same hurdles as other legacy Ada systems around the globe. The new interfaces are built on standard web protocols and need to provide secure reliable information flow to both other internal FAA systems, and external customers such as the major commercial air carriers. In an effort to use best industry practices Lockheed Martin and the FAA chose Java and other web-standard technologies to implement much of the new SWIM interface. Java has gained a strong foothold in the internet environment and the classrooms for a variety of reasons. The result is that Java enjoys a large amount of FOSS and commercial support that makes it a natural choice for such a web interface, even in a high stakes environment such as ATC. ERAM SWIM development has encountered several issues with bridging the gap between Ada and Java and the quickly evolving world of FOSS/COTS SW. Performance issues and command and control issues have dominated our internal discussions and been the focus of much of our effort to achieve test readiness. Efficient data representation, baseline control (remember much of it is FOSS), and debugging have also received a lot of attention. We had a lot of prior experience with mixed languages having several hundred thousand lines of C and C++ and considered ourselves prepared. However, integrating with Java is completely unlike integrating with those others, and we have had to adapt across the board to this new challenge. My talk will focus on the challenges we have encountered, and the lessons we have learned about the strengths and weaknesses of the various languages and other technology elements we have used implementing ERAM SWIM.

Assessment of string tests strategy for an en route air traffic control system

The Federal Aviation Administration (FAA) depends upon several highly available large and complex computer systems to support air traffic control operations. One of the FAA's major initiatives, the Ada based En-Route Automation Modernization (ERAM) program leverages and significantly expands upon previous developed systems. To determine the effectiveness of the string test implementation before full system level testing, the FAA performed an audit of the software requirements that were verified by string tests. An industry standard approach was used to determine the number of Shalls to be inspected. Detailed evaluation using multiple software documents and test plans were compared to the string test results provided by the development contractor. This paper presents details of the audit, its results and reconciliation of the data with the development contractor. The approach to have selected software Shalls verified through the string test method versus full system test resulted in a cost savings of 50% of the cost of the selected software Shalls' full system test, by avoiding duplication of testing efforts. The resulting high pass rate of the audit gave confidence in the development contractor's string test results and also demonstrated a high confidence level in the code, thus confirming the high quality of the Ada code effort.

Federal aviation administration and ada

The US Federal Aviation Administration (FAA) depends upon large, complex and highly available software systems to manage the vast commercial and civil aviation network and to carry out the agency's mission of ensuring high capacity, efficient and extremely safe air travel for the flying public. The FAA's Tower domain provides air traffic control services in the airport environment. There are more than 500 FAA managed Towers. The Terminal Radar Approach Control (TRACON) domain provides air traffic control services in the terminal environment where aircraft are climbing or descending. There are 197 TRACONs. The En Route domain provides air traffic control services typically above 10,000 feet between departure and arrival domains where aircraft achieve their optimal cruise altitude. There are only 21 En Route centers, so each must provide coverage to very large areas. Ada has become a strategic technology in developing and sustaining systems that require high availability and high reliability. The FAA Air Traffic Organization's (ATO) major recent initiative, the En-Route Automation Modernization (ERAM) program goes a long way to reintegrating many disparate system components into a modern composite architecture. This program leverages and significantly expands upon previous Ada based systems, so the FAA has a vital interest in Ada language technology now and for the foreseeable future. Mr. O'Leary will present a federal customer's perspective on systems development and quality, with emphasis on higher reliability, security, and safety. Ada is exceptionally well positioned to support these characteristics, and that is why many current large FAA ATC systems are largely or significantly Ada based. He will touch on past Ada based systems that FAA fielded, the current major ERAM effort, and also where FAA is going in the future with the Next Generation Air Transportation System (NextGen). He will give some insights on what the language and development technologies can contribute towards facilitating the vision of our future. FAA accepts use of DO-278 as a means of assuring systems integrity for Communications, Navigation, Surveillance, and Air Traffic Management (CNS/ATM) software. Ada has also performed well in DO-278.

Time horizon in distributed object societies

In a distributed system, it takes time for a software event to reach remote clients. In the same sense as used in physics, only when the event had reached the time horizon of a client, client becomes aware of it. Using this metaphor , we have developed a simple yet powerful model for software components to get back in sync after interruptions. The ideas described in this paper have been implemented on En Route Automation Modernization (ERAM) program, a Federal Aviation Administration (FAA) effort aimed at replacing the aging en route assets and planting a seed for the many future enhancements that the projected increase in air traffic requires. In many ways, this paper is a compendium to another paper at this same conference titled Publisher Framework (PFW), because it is within the auspices of PFW that these ideas have been implemented.

Publisher FrameWork (PFW)

One of the lasting challenges in building distributed fault tolerant systems is keeping application code size and complexity down. This can be done by capturing the nuances of distributed computing environment and redundant fault tolerant elements into a common infrastructure layer, thus factoring the code that would otherwise need to be written again and again by each distributed fault tolerant software component. When the application code has many complexities, and Air Traffic Control (ATC) is certainly one such example, achieving this goal becomes paramount.Under a project called En Route Automation Modernization (ERAM), the Federal Aviation Administration (FAA) is developing a replacement for its aging en route assets. At the same time, a foundation is being created for the anticipated future enhancements, driven by the projected increase in air traffic. At the core of the ERAM design is a distributed object oriented (OO) framework called Publisher FrameWork (PFW), which is ERAM's answer to the aforementioned OO challenge. This paper describes the PFW properties, the experiences with it accumulated through the first build of the ERAM program, and its applicability to fault tolerant computing.

Data sharing between ada and C/C++

The En Route Automation Modernization (ERAM) program is a real-time Air Traffic Control (ATC) program being developed by Lockheed Martin Corporation. The ERAM program has high availability requirements, mission critical applications, and stringent response time requirements. The estimated size of the ERAM program is 1,300 KSLOC and includes primarily Ada, C, and C++ code. Legacy code being reused in ERAM is both Ada and C. This resulted in the need for several cross-language interfaces. Standard methods for passing binary data structures between the languages have been developed and will be discussed in this paper.