Safety

Airport Exposure to Lightning Strike Hazard in the Contiguous United States

He, Yiyi
Lindbergh, Sarah
Graves, Coolidge
Jasenka Rakas
2021

Reliability of the air transportation system heavily depends on the performance of communication, navigation, and surveillance facilities in the National Airspace System (NAS). These facilities are prone to outages caused by convective weather, such as lightning. Current lightning safety standards and risk assessments focus solely on lightning occurrence and omit the effect of lightning intensity from hazard characterization. We propose methods that incorporate lightning intensity and occurrence parameters to better understand the impact of lightning strike on the NAS using the National...

Dissecting Lightning Strike Hazard Impact Patterns to National Airspace System Facilities in the Contiguous United States

He, Yiyi
Yue, Xiangyu
Lindbergh, Sarah
Gao, Jianxi
Graves, Chuck
Jasenka Rakas
2022

Lightning strikes pose a severe threat to the United States (US) National Airspace System (NAS). Although the US Federal Aviation Administration (FAA) implements lightning protection practices and procedures to protect personnel, electronic equipment, and structures within the NAS, many lightning-induced outages still occur. To date we found that most research on lightning-induced facility outages has focused on understanding the physical processes of lightning strike effects on aircraft and airport ramp operations. Very little research has been done on examining the overall patterns and...

Deep Speech Pattern Analysis of Controller-Pilot Voice Communications for Enhancing Future Aviation Systems Safety

Jasenka Rakas
Sohn, Sungmin
Keslerwest, Lee
Krozel, Jimmy
2023

View Video Presentation: https://doi.org/10.2514/6.2023-4410.vidIn this study, air traffic controller-pilot speech attributes and transcribed texts of voice messages are analyzed to gain insights into air traffic controller-pilot miscommunications. A Deep Speech Pattern (DSP) analysis is used to convert the speech audio into a spectrogram which is broken down into six sound features: loudness, articulation, tempo, rhythm, melody, and timbre. An initial analysis of these six basic features did not reveal enough...

Re-inventing Airport Land Use Planning in California: A Strategy for Updating the California Airport Land Use Planning Handbook — Recommendations for Update of California Airport Land Use Handbook

Jasenka Rakas
Lindbergh, Sarah
University of California, Berkeley. Institute of Transportation Studies
The FAA Consortium in Aviation Operations Research (NEXTOR III)
2024

This report is written in response to the State of California Department of Transportation (Caltrans), Division of Aeronautics, relating to the need to update the 2011 version of the California Airport Land Use Planning (ALUP) Handbook. The purpose of this technical report and its supplementary materials is to provide a robust scientific foundation for the final Handbook update publication for airport land use compatibility planning, which will be created soon by Caltrans. In this study, optimized are visualizations of spatial distribution patterns of aviation accidents across 259 airports...

Controller-Pilot Voice Communication and Intent Monitoring for Future Aviation Systems Safety

Jasenka Rakas
Vallioor, Vishali Kirthi
Krozel, Jimmy
Kostiuk, Peter F.
Mohen, Michael T.
2024

In this study, a set of models and software are developed to support Aviation System Safety Analysis tasks. Three primary models are utilized to conduct the following analyses: (1) Speech Attribute analysis, (2) Speech-to-Text analysis, and (3) Intent Inference analysis. We analyze air traffic controller-pilot speech attributes and transcribed texts of voice messages to gain additional insights into controller-pilot communication dynamics. Such analyses are integrated with situation assessment modules to identify any anomalies in flight trajectories. Key speech attribute patterns are...

Bayesian Network Model of Aviation Safety: Impact of New Communication Technologies on Mid-Air Collisions

Bauranov, Aleksandar
Jasenka Rakas
2024

This article presents a method of estimating the risk of a mid-air collision. The proposed method is an enhancement of the traditional aviation safety model - Integrated Safety Assessment Model (ISAM) - developed by the Federal Aviation Administration (FAA) and EUROCONTROL. ISAM is a mix of event-based models and fault trees that identifies causes of 35 different types of aviation accidents. While useful for conceptual understanding of accidents, the model does not handle human-technical or inter-system interactions. These drawbacks are especially evident when assessing safety impact of...

Implications of Wind Changes and Cross Wind Hazard Exposures at California Airports for Regional Air Mobility

Jasenka Rakas
Hu, Yingjie
Lindbergh, Sarah
2024

California has a large number of public airports, including single-runway general aviation airports and small commercial airports. Because of anticipated changes in future temperature and precipitation in California (CA) and their effect on airports, our study raises a related question: will airports in CA experience any significant changes in wind direction and speed? This issue is especially important to address at single-runway airports where the occurrence of crosswinds exceed 10.5kn. Under such crosswind conditions, it is not safe for smaller/lighter aircraft to land and take-off....

Air Traffic Controller-Pilot Speech Analysis: A Bayesian Statistical Framework for Future Aviation Systems Safety

Vallioor, Vishali Kirthi
Jasenka Rakas
Krozel, Jimmy
Kostiuk, Peter F.
Mohen, Michael T.
2025

This study introduces a logistic regression-based stress level metric to (1) assess stress levels of Air Traffic Controllers (ATC) and pilots, and (2) detect off-nominal events using audio-derived features. With over 16,264 labeled ATC-pilot utterances and scalar and multi-dimensional speech attributes, it is demonstrated that a developed Stress Score metric can capture meaningful distinctions between the nominal and off-nominal utterances. The Beta distribution fit further captures the skewed nature of Stress Scores, indicating that the model follows a non-linear but quantifiable pattern...

Light Rail System Safety Improvements Using ITS Technologies

Chira-chavala, Ted
Coifman, Ben
Empey, Dan
Mark Hansen
Lechner, Ed
Porter, Chris
1997

This report describes research which studied identifying and analyzing the effectiveness of countermeasures designed to reduce light rail crashes. Focus is in collisions with road vehicles at intersections. The light rail system for the Santa Clara County Transportation Agency in California served as the focus of the study.

Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System

Abkin, Michael H.
Gilgur, Alexander
Bobick, John C.
Hansman, R. John
Reynolds, Tom G.
Vigeant-Langlois, Laurence
Mark Hansen
Gosling, Geoffrey D.
Baumgardner, William F.
2002

This report constitutes the final report for Calendar Year 2001 (CY01) under Contract Number NAS2-99072 for the third year of a three-year research project entitled “Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System.” The objective of this research is to investigate and develop techniques to enable NAS fast-time simulation modeling to be useful for conducting safety analysis. The research efforts focus on examining the type of safety issues that could be appropriately modeled by fast-time simulations and developing, testing, and...