Hernando Jimenez

Technology Assessment of NASA Environmentally Responsible Aviation Advanced Vehicle Concepts

The National Aeronautics and Space Administration’s (NASA) Environmentally Responsible Aviation (ERA) project is conducting research at an integrated system level on promising concepts and technologies expected to mature in the N+2 time frame. ERA has a need to perform a systems level analysis of these concepts and technologies to estimate and track performance towards ERA’s goal of simultaneously achieving improvement in metrics for fuel burn reduction, noise margin, and LTO NOx emissions reduction. This paper describes work done for the system level comparison of tube and wing versus hybrid wing body airframe configurations using both advance ultra high bypass ratio direct drive and geared turbofan engines. The results focus on the interdependencies between the ERA fuel burn and noise metrics.

Updates and Modeling Enhancements to the Assessment of NASA Environmentally Responsible Aviation Technologies and Vehicle Concepts

The National Aeronautics and Space Administration’s (NASA) Environmentally Responsible Aviation (ERA) project is conducting research at an integrated system level on promising concepts and technologies expected to mature in the N+2 time frame. It is essential for ERA to perform a systems level analysis of these concepts and technologies in order to estimate and track performance towards ERA’s goal of simultaneously achieving improvement in metrics for fuel burn reduction, noise margin, and LTO NOx emissions reduction. Previous vehicle modeling and technology assessment work conducted for the ERA project illustrated system level comparison of tube and wing versus hybrid wing body airframe configurations, as well as between ultra high bypass ratio direct drive and geared turbofan engines. Guidance drawn from these results has led to an updated list of ERA technologies of interest. Additionally, development of improved modeling capabilities and a better understanding of key technology impacts have been accordingly incorporated into an updated technology assessment. This assessment evaluates changes to the technology portfolio, incorporates updated technology assumptions, augmented vehicle and technology models, and includes for the first time LTO NOx estimates for advanced combustors. These new set of results allow for an understanding of the interdependencies between each of the ERA metrics and provide an update on ERA’s capability of achieving its goals.

A third-party casualty risk model for unmanned aircraft system operations

Unmanned Aircraft System (UAS) integration into the National Airspace System (NAS) is an important goal of many members of the Aerospace community including stakeholders such as the military, law enforcement and potential civil users of UAS. However, integration efforts have remained relatively limited due to safety concerns. Due to the nature of UAS, safety predictions must look beyond the system itself and take the operating environment into account. A framework that can link UAS reliability and physical characteristics to the effects on the bystander population is required. This study proposes using a Target Level of Safety approach and an event tree format, populated with data from existing studies that share characteristics of UAS crashes to enable casualty prediction for UAS operations.

Development of Aerodynamic Modeling and Calibration Methods for General Aviation Aircraft Performance Analysis - a Survey and Comparison of Models

Aircraft flight safety has been a main issue in General Aviation (GA) area. It is important to generate an accurate aerodynamic model of GA aircraft in order to understand the aircraft performance in the entire regime of aircraft operations. Several aerodynamic modeling and calibration methods for a general aviation aircraft are surveyed, examined, and compared in this study. Based on the well-established aerodynamic model, the model is extended to the post-stall regime to estimate the post-stall aerodynamic characteristics in the extreme regime. The developed model in this study was validated using historical and published data for Cessna 172S aircraft.

Fleet Assessment of Fuel Burn and NOx Emissions for NASA Environmentally Responsible Aviation (ERA) Technologies and Concepts

A system-wide model for fuel burn and NOx emissions is presented whereby the introduction of NASAs Environmentally Responsible Aviation aircraft technologies on future vehicles can be assessed with respect to fleet-level environmental impact. This model extends upon prior work in three ways: Improvements in operations balancing and allocation logic yield fuel burn estimates that more closely match empirical data for domestic and international operations; enhancements to vehicle environmental performance models offer a better representation of the updated ERA technology portfolio; parametric NOx emissions models for full-flight as well as departure and arrival segments are integrated into the existing system-wide model to offer fleet-level NOx estimates. Results for scenarios featuring varying levels of ERA technology introduction into the fleet are presented that characterize potential benefits achievable. Results suggest that significant reductions for local emissions can be attained, whereas total emissions closely follow favorable fuel burn improvements.

System-wide Fleet Assessment of NASA Environmentally Responsible Aviation (ERA) Technologies and Concepts for Fuel Burn and CO 2

A method for assessing the impact of vehicle technologies and new aircraft concepts at the fleet level is presented. Various aspects of the method constitute a departure from standard practice intended to address known shortcomings and advance the state of the art. In particular, an operational activity growth routine is implemented where operational sets are grown to match top-level and airport level forecasts that are fully balanced for all origindestination airport pairs. The proposed approach also features a novel fleet evolution scheme where replacements are devised on the basis of mission capabilities for aircraft types rather than on seat-classes, and the retirement of aircraft is applied to models introduced beyond the reference year. Surrogate models of fuel burn are regressed from gold-standard modeling tools, and are shown to be suitable for system-wide assessments on the basis of model representation accuracy. Fleet assessment results are shown for various technology

A Morphological Approach for Proactive Risk Management in Civil Aviation Security

In this study, morphological analysis is used to develop a framework for proactively assessing the risk of a terrorist attack on the air transportation system. Morphological analysis, a first order method pioneered by Fritz Zwicky, is employed to exhaustively create possible attack scenarios. Morphological analysis is then used to assess the likelihood of each scenario. Given a consequence estimation method, the risk for each of these scenarios can be determined. A method for developing profiles of various terror organizations is outlined and, given this information, a more specific assessment of high-risk scenarios can be made. Using the method developed herein, defensive organizations would have the capability to quickly assess how risky various terrorist attack scenarios are, and therefore more effectively protect our air transportation systems from those who would attack it for their own political or ideological gain.

Characterization of Technology Integration Based on Technology Readiness Levels

Integration is ubiquitous in systems development. Although much has been written about the need to explicitly characterize integration in the context of technology development and maturation, current technology readiness level evaluation methods do so implicitly or altogether incorrectly. It is argued that integration is an inherent subattribute of technology readiness and that technology readiness level descriptions hold some of the conceptual building blocks with which such an explicit characterization of integration may be constructed. To do so, the concept of integration in the context of technology maturation is elaborated on, drawn from well-established published work to generate characterizations of integration for each readiness level. These descriptions build upon fundamental concepts of systems integration such as system architectures, abstraction, interfaces, and interactions. The use of these generic descriptions to create specific ones for a representative emerging technology in aeronautics i...

Challenges and Opportunities in Flight Data Mining: A Review of the State of the Art

Incident and accident rates of rotorcraft and fixed-wing general aviation operations are considerably higher than those of commercial aviation. Efforts to improve the safety record of the former have drawn attention on flight data monitoring (FDM), also referred to as flight operations quality assurance (FOQA), as a voluntary safety mechanism for data collection with on-board recorders, analysis, and monitoring for the effectiveness of corrective measures. Flight data monitoring is regularly implemented in commercial operations where the application of data mining techniques has been proposed and demonstrated for anomaly detection. This paper surveys data mining techniques aimed at the reader with little or no prior exposure to this topic, as well as a review of published work on applications to flight data. It then provides an examination of challenges and opportunities for its application in rotorcraft and general aviation operations, where it has yet to be demonstrated on a large scale.

Probabilistic Technology Assessment for NASA Environmentally Responsible Aviation (ERA) Vehicle Concepts

We present and demonstrate different approaches of subjective probability encoding pertinent to technology impact modeling for probabilistic assessment of advanced vehicle concepts. Results are generated and discussed using NASA Environmentally Responsible Aviation as a relevant technology development and integration effort. We show that different techniques are suitable and can be selected on the basis of available technology impact information, and that significant differences are observed on the results across alternative methods. Uncertainty on percent fuel burn reduction and cumulative noise margin below Stage 4 is observed to be within 5% and 3 dB respectively. The impact and variability of technologies on noise margin for the hybrid wing body concept is also notably dominated by the inherent noise shielding benefits of this configuration.