Safety Analysis for Advanced Separation Concepts

Andrews, J.W.; Erzberger, Heinz; Welch, Jerry D.

doi:10.2514/atcq.14.1.5

Cited by 31 publications

(31 citation statements)

References 4 publications

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“…The first used a fault tree approach to study four fault types: (1) nominal conditions, (2) information fault non-conformance, (3) control fault non-conformance, and (4) service interruption. 6 Results of this study suggest AAC could achieve the safety levels expected in 20-30 years given the deployment of appropriately designed safety features. Although risk estimates can be computed quickly using the fault tree method, it does not facilitate component-level model fidelity because the number of conditional probabilities and failure modes grows exponentially.…”

Section: Introductionmentioning

confidence: 78%

“…7,13 ), then TCAS fails and there is a 30% chance that pilots will not be able to visually detect and avoid the NMAC. 6 In that case, there is a 28% chance of collision. Onboard speaker (AC1) N/A (same as S1 above) S2…”

Section: Tcas and Pilot Visual Avoidancementioning

confidence: 99%

“…7 As such, all assumptions and simplifications made in the previous study are also present here. They must be examined more closely because they can affect the estimates of NMAC (defined as separation of less than 500 ft vertically and 100 ft horizontally 6 ) and collision risk. An abridged list of the most important ones is given below:…”

Section: A Simulation Assumptions and Simplificationsmentioning

confidence: 99%

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Accelerated Monte Carlo Simulation for Safety Analysis of the Advanced Airspace Concept

Thipphavong

2010

10th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference

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Safe separation of aircraft is a primary objective of any air traffic control system. An accelerated Monte Carlo approach was developed to assess the level of safety provided by a proposed next-generation air traffic control system. It combines features of fault tree and standard Monte Carlo methods. It runs more than one order of magnitude faster than the standard Monte Carlo method while providing risk estimates that only differ by about 10%. It also preserves component-level model fidelity that is difficult to maintain using the standard fault tree method. This balance of speed and fidelity allows sensitivity analysis to be completed in days instead of weeks or months with the standard Monte Carlo method. Results indicate that risk estimates are sensitive to transponder, pilot visual avoidance, and conflict detection failure probabilities.

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Section: Introductionmentioning

confidence: 78%

Section: Tcas and Pilot Visual Avoidancementioning

confidence: 99%

Section: A Simulation Assumptions and Simplificationsmentioning

confidence: 99%

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Accelerated Monte Carlo Simulation for Safety Analysis of the Advanced Airspace Concept

Thipphavong

2010

10th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference

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“…The safety of ground-based automated separation was the subject of a recent study 7 that presented a preliminary fault-tree analysis of the effect of some system faults on the safety of a centralized separation system. The analysis did not consider system uncertainties or performance degradation, nor did it consider prediction errors.…”

Section: Introductionmentioning

confidence: 99%

Safety Performance of Airborne Separation: Preliminary Baseline Testing

Consiglio

Hoadley²,

Wing³

et al. 2007

7th AIAA ATIO Conf, 2nd CEIAT Int'l Conf on Innov and Integr in Aero Sciences,17th LTA Systems Tech Conf; Followed by 2nd TEOS

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The Safety Performance of Airborne Separation (SPAS) study is a suite of Monte Carlo simulation experiments designed to analyze and quantify safety behavior of airborne separation. This paper presents results of preliminary baseline testing. The preliminary baseline scenario is designed to be very challenging, consisting of randomized routes in generic high-density airspace in which all aircraft are constrained to the same flight level. Sustained traffic density is varied from approximately 3 to 15 aircraft per 10,000 square miles, approximating up to about 5 times today's traffic density in a typical sector. Research at high traffic densities and at multiple flight levels are planned within the next two years. Basic safety metrics for aircraft separation are collected and analyzed. During the progression of experiments, various errors, uncertainties, delays, and other variables potentially impacting system safety will be incrementally introduced to analyze the effect on safety of the individual factors as well as their interaction and collective effect. In this paper we report the results of the first experiment that addresses the preliminary baseline condition tested over a range of traffic densities. Early results at five times the typical traffic density in today's NAS indicate that, under the assumptions of this study, airborne separation can be safely performed. In addition, we report on initial observations from an exploration of four additional factors tested at a single traffic density: broadcast surveillance signal interference, extent of intent sharing, pilot delay, and wind prediction error. Nomenclature

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“…The automation is designed to detect conflicts between aircraft and generate conflict resolution routes and conflict-free maneuvering advisories 7,8,9 . Until now, safety evaluation of SA applications has, for the most part, been based on studies using simulation tools that seldom include models of system uncertainties 10,11,12 and often make many simplifying assumptions such as perfect navigation performance and absence of prediction errors or off-nominal conditions. Analytical and numerical approaches to the analysis of safety using uncertainty propagation models often require many simplifying assumptions to keep the size of the models manageable or computation time within reasonable limits 13 .…”

Section: Introductionmentioning

confidence: 99%

Impact of Pilot Delay and Non-Responsiveness on the Safety Performance of Airborne Separation

Consiglio

Hoadley

Wing

et al. 2008

The 26th Congress of ICAS and 8th AIAA ATIO

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Assessing the safety effects of prediction errors and uncertainty on automationsupported functions in the Next Generation Air Transportation System concept of operations is of foremost importance, particularly safety critical functions such as separation that involve human decision-making. Both ground-based and airborne, the automation of separation functions must be designed to account for, and mitigate the impact of, information uncertainty and varying human response. This paper describes an experiment that addresses the potential impact of operator delay when interacting with separation support systems. In this study, we evaluated an airborne separation capability operated by a simulated pilot. The experimental runs are part of the Safety Performance of Airborne Separation (SPAS) experiment suite that examines the safety implications of prediction errors and system uncertainties on airborne separation assistance systems. Pilot actions required by the airborne separation automation to resolve traffic conflicts were delayed within a wide range, varying from five to 240 seconds while a percentage of randomly selected pilots were programmed to completely miss the conflict alerts and therefore take no action. Results indicate that the strategic ASAS functions exercised in the experiment can sustain pilot response delays of up to 90 seconds and more, depending on the traffic density. However, when pilots or operators fail to respond to conflict alerts the safety effects are substantial, particularly at higher traffic densities. Nomenclature

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Safety Analysis for Advanced Separation Concepts

Abstract: Aviation planners have called for increasing the capacity of the air transportation system by factors of two or three over the next 20 years.

Cited by 31 publications

References 4 publications

Accelerated Monte Carlo Simulation for Safety Analysis of the Advanced Airspace Concept

Accelerated Monte Carlo Simulation for Safety Analysis of the Advanced Airspace Concept

Safety Performance of Airborne Separation: Preliminary Baseline Testing

Impact of Pilot Delay and Non-Responsiveness on the Safety Performance of Airborne Separation

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