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All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Designing Flight Deck Procedures

Three reports address the design of flight-deck procedures and various aspects of human interaction with cockpit systems that have direct impact on flight safety. One report, On the Typography of Flight- Deck Documentation, discusses basic research about typography and the kind of information needed by designers of flight deck documentation. Flight crews reading poorly designed documentation may easily overlook a crucial item on the checklist. The report surveys and summarizes the available literature regarding the design and typographical aspects of printed material. It focuses on typographical factors such as proper typefaces, character height, use of lower- and upper-case characters, line length, and spacing. Graphical aspects such as layout, color coding, fonts, and character contrast are discussed; and several cockpit conditions such as lighting levels and glare are addressed, as well as usage factors such as angular alignment, paper quality, and colors. Most of the insights and recommendations discussed in this report are transferable to paperless cockpit systems of the future and computer-based procedure displays (e.g., "electronic flight bag") in aerospace systems and similar systems that are used in other industries such as medical, nuclear systems, maritime operations, and military systems.

Degani, Asaf↗
NASA NTRS1974

Configuration management during transition for a powered lift STOL aircraft

Presented in this paper are the analytical and moving-base simulation results of a study to improve flight safety and operations of V/STOL type aircraft. One of the more significant and novel aspects of the work accomplished has been the concept and implementation of a configuration management flight control system designed to take the guesswork out of, and improve the operational safety of, transition flight in the region from cruise to STOL.

Johnson, W. A.↗
NASA NTRS1995

Simulator Investigation of Pilot Aids for Helicopter Terminal Area Operations with One Engine Inoperative

Two recent piloted simulation experiments have investigated advanced display concepts applied to civil transport helicopter terminal area operations. Civil Category A helicopter operations apply to multi-engine helicopters wherein a safe recovery (land or fly out) is required in the event of a single engine failure. The investigation used the NASA Ames Research Center Vertical Motion Simulator, which has a full six degrees of freedom, to simulate the flight task as closely as possible. The goal of these experiments was to use advanced cockpit displays to improve flight safety and enhance the mission performance of Category A terminal area operations in confined areas. The first experiment investigated the use of military display formats to assist civil rotorcraft in performing a Category A takeoff in confined terminal areas. Specifically, it addressed how well a difficult hovering backup path could be followed using conventional instruments in comparison to panel mounted integrated displays. The hovering backup takeoff, which enables pilots to land back to the confined area pad in the event of an engine failure, was chosen since it is a difficult task to perform. Seven NASA and Army test pilots participated in the experiment. Evaluations, based on task performance and pilot workload, showed that an integrated display enabled the pilot to consistently achieve adequate or desired performance with reasonable pilot workload. Use of conventional instruments, however, frequently resulted in unacceptable performance (poor flight path tracking), higher pilot workload, and poor situational awareness. Although OEI landbacks were considered a visual task, the improved performance on the backup portion, in conjunction with increased situational awareness resulting from use of integrated displays, enabled the pilots to handle an engine failure and land back safely. In contrast, use of conventional instruments frequently led to excessive rates of sink at touchdown. A second simulation (in progress - July - August) is being conducted to investigate the use of advanced displays to perform vertical and short takeoffs and landings. One Engine Inoperative trajectories, which were optimized based on safety of flight restrictions, are utilized. Based on comments from the first experiment and further analytic development, appropriate fly out and approach guidance was added. Displays include conventional instruments with raw data, and the following integrated displays: multi-view and side-view hover displays based on the Apache Pilot Night Vision System, and variations of the pathway-in-the-sky displays with a flight-path-vector, a leader and flight director modifications. Panel mounted and head-up displays are being evaluated. Engine modifications have been incorporated to simulate 30 second and 2 minute contingency power ratings. Evaluations are based on task performance and pilot workload. NASA, Army, FAA, and industry test pilots participated. Details concerning the design, conduct, and the results of the experiment will be reported in the proposed paper.

Iseler, Laura↗
NASA NTRSDate not supplied

An Interim Set of TNT Curves for LOX/LNG Explosions

Space launch companies are actively developing, or in some cases have already developed, new vehicles that use large quantities of liquid oxygen (LOX) and liquid natural gas (LNG) propellants. This propellant mixture currently lacks sound/verified LOX/LNG explosive safety standards for use in explosive siting and flight safety analysis. In the U.S., multiple government and commercial organizations have conducted limited testing, or are preparing to conduct tests, intended to provide a sound technical basis for explosive standards applicable to space launch vehicle ground and flight operations. The limited testing and analysis conducted so far indicates the potential to produce extremely energetic explosions due to the miscibility of LOX/LNG (methane), a unique feature relative to previously used propellant mixtures such as hydrogen/oxygen or kerosene/oxygen. MOX is a homogenous mixture of methane and oxygen that is possible because of methane’s 100% miscibility in LOX. Preliminary testing by N2L, Inc. described in this paper shows that it is possible to form MOX with a variety of mixing methods, and that MOX is a sensitive high explosive capable of producing overpressures greater than comparable masses of C-4. The limited amount and quality of large-scale LOX/LNG explosive test data, and the potential formation of high-explosive MOX, create significant unknowns in the determination of hazard areas (cleared of the public) for ground operations (such as a static fire test) and flights of launch vehicles with LOX/LNG propellant. This paper will review the methods used by NASA to develop and validate the LOX/LH2 blast model using large-scale explosive test programs such as Project PYRO, the Hydrogen-Oxygen Vertical Impact (HOVI), and the Large-Scale Hydrogen-Oxygen Explosion (LSHOE) tests. This paper will describe how the same process was used to prepare an interim LOX/LNG blast model that applies to various LV failure scenarios and conservatively accounts for potential MOX formation. This paper also summarizes past and future testing and modeling efforts funded by a consortium of NASA, the US Federal Aviation Administration (FAA), and the US Space Force (USSF). These test programs should be concluded within the next 3 years and are intended to provide empirical data for model verification and validation.

Liquid Oxygen↗
NASA NTRSDate not supplied

An Interim Set of TNT Curves for LOX/LNG Explosions

Space launch companies are actively developing, or in some cases have already developed, new vehicles that use large quantities of liquid oxygen (LOX) and liquid natural gas (LNG) propellants. This propellant mixture currently lacks sound/verified explosive safety standards for use in explosive siting and flight safety analysis. In the U.S., multiple government and commercial organizations have conducted limited testing, or are preparing to conduct tests, intended to provide a sound technical basis for LOX/LNG explosive standards applicable to space launch vehicle ground and flight operations. The limited testing and analysis conducted so far indicates the potential to produce extremely energetic explosions due to the miscibility of LOX/LNG (methane), a unique feature relative to previously used propellant mixtures such as hydrogen/oxygen or kerosene/oxygen. MOX is a homogenous mixture of methane and oxygen that is possible because of methane’s 100% miscibility in LOX. Preliminary testing by N2L, Inc. described in this paper shows that it is possible to form MOX with a variety of mixing methods, and that MOX is a sensitive high explosive capable of producing overpressures greater than comparable masses of C-4. The limited amount and quality of large-scale LOX/LNG explosive test data, and the potential formation of high-explosive MOX, create significant unknowns in the determination of hazard areas (cleared of the public) for ground operations (such as a static fire test) and flights of launch vehicles with LOX/LNG propellant. This paper will review the methods used by NASA to develop and validate the LOX/LH2 blast model using large-scale explosive test programs such as Project PYRO, the Hydrogen-Oxygen Vertical Impact (HOVI), and the Large-Scale Hydrogen-Oxygen Explosion (LSHOE) tests. This paper will describe how the same process was used to prepare an interim LOX/LNG blast model that applies to various LV failure scenarios and conservatively accounts for potential MOX formation. This paper also summarizes past and future testing and modeling efforts funded by a consortium of NASA, the US Federal Aviation Administration (FAA), and the US Space Force (USSF). These test programs should be concluded within the next 3 years and are intended to provide empirical data for model verification and validation.

Liquid Oxygen↗
NASA NTRS1971

A proposed criterion for aircraft flight in turbulence

A proposed criterion for aircraft flight in turbulent conditions is presented. Subjects discussed are: (1) the problem of flight safety in turbulence, (2) new criterion for turbulence flight where existing ones seem adequate, and (3) computational problems associated with new criterion. Primary emphasis is placed on catastrophic occurrences in subsonic cruise with the aircraft under automatic control. A Monte Carlo simulation is used in the formulation and evaluation of probabilities of survival of an encounter with turbulence.

Porter, R. F.↗
NASA NTRS1991

Space Station Freedom/lunar transfer vehicle propellant operation hazard analysis

Space Station Freedom (SSF), as a transportation node for Space Exploration Initiative missions, would involve the assembly and refurbishing of lunar and Mars transfer vehicles. This includes operations involving cryogenic propellants (LH2 7 LO2) such as storing and handling of loaded propellant tanks, assembly onto the vehicle, and propellant transfer. Cryogenic propellants dictate rigorous safety precautions and impose unique requirements to ensure flight safety to both personnel and SSF elements. The objective of this study is to identify potential hazards and risks associated with cryogenic propellants. This involves identification of pertinent system design features and operational procedures. Criticality of identified risks/hazards shall be assessed and those that fall in the catastrophic and critical categories shall include mitigating solutions.

Dominick, Sam↗
NASA NTRS2016

Wake-Induced Aerodynamics on a Trailing Aircraft

NASA conducted flight tests to measure the exhaust products from alternative fuels using a DC-8 transport aircraft and a Falcon business jet. An independent analysis of the maximum vortex-induced loads on the Falcon in the DC-8 wake was conducted for pre-flight safety analysis and to define safe trail distances for the flight tests. Static and dynamic vortex-induced aerodynamic loads on the Falcon were predicted at a matrix of locations aft of the DC-8 under flight-test conditions, and the maximum loads were compared with design limit loads to assess aircraft safety. Trajectory simulations for the Falcon during close encounters with the DC-8 wake were made to study the vortex-induced loads during traverses of the DC-8 primary trailing vortex. A parametric study of flight traverses through the trailing vortex was conducted to assess Falcon flight behavior and motion characteristics.

Mendenhall, Michael R.↗
NASA NTRS1983

Advanced structures technology and aircraft safety

NASA research and development on advanced aeronautical structures technology related to flight safety is reviewed. The effort is categorized as research in the technology base and projects sponsored by the Aircraft Energy Efficiency (ACEE) Project Office. Base technology research includes mechanics of composite structures, crash dynamics, and landing dynamics. The ACEE projects involve development and fabrication of selected composite structural components for existing commercial transport aircraft. Technology emanating from this research is intended to result in airframe structures with improved efficiency and safety.

Mccomb, H. G., Jr.↗
NASA NTRS2017

An Assessment of Reduced Crew and Single Pilot Operations in Commercial Transport Aircraft Operations

Future reduced crew operations or even single pilot operations for commercial airline and on-demand mobility applications are an active area of research. These changes would reduce the human element and thus, threaten the precept that "a well-trained and well-qualified pilot is the critical center point of aircraft systems safety and an integral safety component of the entire commercial aviation system." NASA recently completed a pilot-in-the-loop high fidelity motion simulation study in partnership with the Federal Aviation Administration (FAA) attempting to quantify the pilot's contribution to flight safety during normal flight and in response to aircraft system failures. Crew complement was used as the experiment independent variable in a between-subjects design. These data show significant increases in workload for single pilot operations, compared to two-crew, with subjective assessments of safety and performance being significantly degraded as well. Nonetheless, in all cases, the pilots were able to overcome the failure mode effects in all crew configurations. These data reflect current-day flight deck equipage and help identify the technologies that may improve two-crew operations and/or possibly enable future reduced crew and/or single pilot operations.

Bailey, Randall E.↗
NASA NTRS1971

NASA Aircraft Safety and Operating Problems, Volume 1

The proceedings of the Conference on NASA Aircraft Safety and Operating Problems held at Langley Research Center, Hampton, Virginia, on May 4-6, 1971, are reported in this NASA Special Publication. The purpose of this conference was to discuss the results of research of the National Aeronautics and Space Administration in the field of aircraft safety and operating problems. The unclassified program components include the following: Flight Safety Airway and Runway Environment Operational Experience With Subsonic Cruise Aircraft Cockpit Environment Terminal Area Operations Flight Environment Induced Environmental Effects Contributions to this compilation were made by representatives from Ames, Flight, Langley, and Lewis Research Centers, Manned Spacecraft Center, George C. Marshall Space Flight Center, the University of Virginia, the Research Triangle Institute, and the Federal Aviation Administration .

Aircraft Safety Office↗
NASA NTRS1996

Cross-Cultural Barriers to Effective Communication in Aviation

Communication is essential to safe flight, as evidenced by several accidents in which crew communicates was found to have contributed to the accidents. This chapter documents the essential role of explicit efficient communication to flight safety with a global context. It addresses communication between flight crews and air traffic controllers in regions a the world where pilots and controllers speak different native languages, as well as cases in which crew members within the flight deck represent different native languages and cultures. It also addresses problems associated with "exporting" crew resource management training programs to parts of the world which values and norms differ from those of the United States, where these programs were initially developed. This chapter is organized around several central questions: (1) What are various kinds of communication failures and what are their consequences; (2) What are the causes of communication failure; (3) What are features of effective crew communication; (4) What can be done to enhance communication success? To explore a wider range of communication failures than available from accident reports, we examined a set of incident reports from the Aviation Safety Reporting System. These could be classified into three major categories: those in which language actually interfered with transmission of a message; those in which transmission was adequate but the context was not expressed unambiguously and thus the message received was not the same as the message intended; and those in which the message was received as intended, but was not adequately understood or acted upon, mainly because of cultural factors. The consequences of failed communication can be flight errors (such as when a clearance is not received correctly), loss of situation awareness, or failure of crew members (or ATC and pilots) to build a shared understanding of a situation. Causes of misunderstanding can be traced to a number of sources, often grounded in faulty assumptions held by one or both parties to a conversation. Speakers and listeners often experience "illusionary understanding" in which they think they understand each other, but in fact do not. While this problem can exist within a single culture, it is much more serious across cultures. Training in effective explicit communication is a component of Crew Resource Management training programs developed in the U.S. These programs are being adopted by airlines around the world, with varying degrees of success. The level of success in part depends on how similar the conversational and social styles of those cultures are to those of the U.S. A factor that influences conversational style is a culture's relative positioned on two major dimensions that distinguish national cultural groups: individualism vs. collectivism and degree of power distance. The chapter concludes with a discussion of techniques for overcoming the various classes of communication failures and for effectively adapting training programs to fit the values and norms of cultures around the globe.

Fischer, U.↗
NASA NTRS1999

Development of An Intelligent Flight Propulsion Control System

The initial design and demonstration of an Intelligent Flight Propulsion and Control System (IFPCS) is documented. The design is based on the implementation of a nonlinear adaptive flight control architecture. This initial design of the IFPCS enhances flight safety by using propulsion sources to provide redundancy in flight control. The IFPCS enhances the conventional gain scheduled approach in significant ways: (1) The IFPCS provides a back up flight control system that results in consistent responses over a wide range of unanticipated failures. (2) The IFPCS is applicable to a variety of aircraft models without redesign and,(3) significantly reduces the laborious research and design necessary in a gain scheduled approach. The control augmentation is detailed within an approximate Input-Output Linearization setting. The availability of propulsion only provides two control inputs, symmetric and differential thrust. Earlier Propulsion Control Augmentation (PCA) work performed by NASA provided for a trajectory controller with pilot command input of glidepath and heading. This work is aimed at demonstrating the flexibility of the IFPCS in providing consistency in flying qualities under a variety of failure scenarios. This report documents the initial design phase where propulsion only is used. Results confirm that the engine dynamics and associated hard nonlineaaities result in poor handling qualities at best. However, as demonstrated in simulation, the IFPCS is capable of results similar to the gain scheduled designs of the NASA PCA work. The IFPCS design uses crude estimates of aircraft behaviour. The adaptive control architecture demonstrates robust stability and provides robust performance. In this work, robust stability means that all states, errors, and adaptive parameters remain bounded under a wide class of uncertainties and input and output disturbances. Robust performance is measured in the quality of the tracking. The results demonstrate the flexibility of the IFPCS architecture and the ability to provide robust performance under a broad range of uncertainty. Robust stability is proved using Lyapunov like analysis. Future development of the IFPCS will include integration of conventional control surfaces with the use of propulsion augmentation, and utilization of available lift and drag devices, to demonstrate adaptive control capability under a greater variety of failure scenarios. Further work will specifically address the effects of actuator saturation.

Calise, A. J.↗
NASA NTRS2013

NASA Activity Update for the 2013 Unmanned Vehicle Systems International (UVSI) Yearbook

This year s report offers a high level perspective on some of the UAS related activities in which NASA is involved, both internal and external to the agency. Internally, NASA issued UAS operational policy on certification of NASA UAS and aircrew. A team of NASA UAS experts and operators analyzed all current procedures and best practices to design the policy. An update to the agencies Aircraft Operations Management Manual incorporated a new chapter to address UAS planning, preflight operations, flight operations, flight crew requirements, airworthiness and flight safety reviews. NASA UAS are classified into three categories based on weight and airspeed. Aircrews, including observers, are classified by how they interface with the UAS, and the policy defines qualifications, training, and currency. The NASA flight readiness approval process identifies risks and mitigations in order to reduce the likelihood and/or consequence of the risk to an acceptable level. The UAS operations process incorporates all aspects of airworthiness, flight standards and range safety exactly the same processes used for NASA manned aircraft operations. NASA has two internal organizations that routinely operate UAS. The Science Mission Directorate utilizes UAS as part of its Airborne Science Program and is the most frequent operator of NASA UAS in both national and international airspace. The Aeronautics Research Mission Directorate conducts UAS flight operations in addition to conducting research important to the UAS community. This past year the Science Mission Directorate supported the Hurricane and Severe Storm Sentimental (HS3) Mission with two NASA Global Hawk platforms. HS3 is a five-year mission specifically targeted to investigate the processes that underlie hurricane formation. During the 2012 portion of this mission the Global Hawk overflew hurricanes Leslie and Nadine in the Atlantic Ocean completing 6 flights and accumulating more than 148 flight hours. Another multi-year mission was initiated last year when the Sensor Integrated Environmental Remote Research Aircraft (SIERRA) UAS began surveying faults in California s Surprise Valley. A team of scientists and engineers from the United States Geological Survey (USGS), NASA Ames Research Center, Central Washington University, and Carnegie Mellon University will measure magnetic fields using ground surveys and the SIERRA to map the geophysics below the surface of Surprise Valley. The data collected will be used to generate 3D maps of the geophysical data of the area. The Aeronautics Mission Directorate continues its collaboration with Boeing to conduct UAS flight operations of the X-48C, a modified version of the X-48B originally built by Cranfield Aerospace, United Kingdom. The Aeronautics Mission Directorate utilizes vehicles of this size for a wide variety of research studies. Most of these operations are conducted within restricted airspace. The Aeronautics Research Mission Directorate also sponsors the UAS in the National Airspace System (NAS) Project, which is working in close cooperation with the Federal Aviation Administration (FAA) to address critical challenges associated with routine UAS operations in civil airspace. The project is focused on separation assurance and collision avoidance systems and algorithms, command and control for non-military operations including spectrum allocation requirements, human system interaction issues, and safety and certification topics.

Bauer, Jeffrey E.↗
NASA NTRSDate not supplied

Uncertainty Quantification of Expected Time-of-Arrival in UAV Flight Trajectory

One of the foremost requirements for accurate in-flight safety monitoring of autonomous unmanned aerial vehicles (UAVs) is tracking of their flight trajectory. Existing UAVs leverage autonomous flight functionalities based on trajectory generation algorithms developed in robotic applications such as polynomial or spline curves in order to facilitate kinematic smoothness, minimum vibrations and fuel efficiency. However in practice, the actual path may be subjected to unexpected local weather conditions, unexpected obstacles along the path or abrupt traffic changes in the low-altitude airspace resulting in large errors of the predicted time-of-arrival at way-points. In this study, an approach to quantify and propagate uncertainty in 4D trajectories is proposed. The paper presents a simple error interval propagation method based on the expected cruise speed of the UAV and its associated uncertainty. The uncertainty is then propagated in time to estimate reasonable confidence intervals on the times-of-arrival of the vehicle at each way-point as well as along the entire flight-path. The uncertainty propagation is demonstrated on a state-of-the-art trajectory generation algorithm based on non-uniform rational B-spline (NURBS) curves. Further, the effect of a stationary wind field is incorporated in the uncertainty propagation approach. The proposed method is implemented on synthetic and real data obtained from flight experiments with a small UAV.

Uncertainty Quantification↗
NASA NTRSDate not supplied

Gathering Safety Intelligence from Relevant Safety Events

The notion of Safety II grew out of the realization that people are the source of resilience in any given socio-technical system and that people, in fact, produce safety far more often than reduce safety. The talk will highlight some of the key differences between Safety I and Safety II in their assumptions about the nature of operations and the nature of safety as well as some of the limitations of each approach and the ways in which they complement each other. Because we all want to make data-informed decisions and because we already collect a lot of Safety I-type data, the talk will also describe the Flight Safety Foundation’s Learning from All Operations effort which is designed to collect Safety II-type data.

resilience↗
NASA NTRS2005

Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

Jentink, Henk W.↗
NASA NTRSDate not supplied

The Contribution of Pilots to Resilience in Normal Operations: A Survey Approach

Much of our knowledge about human performance in flight safety has come from the analysis of undesired events, whether accidents, incidents, or crew behaviors identified via flight exceedance monitoring or observational techniques. In recent years, there has been an acknowledgement that operational personnel are not merely sources of “human error”, but also make a unique human contribution to safe outcomes. In a few celebrated cases, this takes the form of “heroic saves”, but on many more occasions, operational personnel contribute to safety through everyday, often-unnoticed actions that turn potentially hazardous situations into non-events. An emerging approach to safety, frequently referred to as “Safety II,” proposes that the positive human contribution is an important and largely untapped source of safety information. Some airlines have successfully trained observers to identify and record the positive behaviors exhibited by the crew over the course of a flight. In other cases, flight crew are interviewed about good practices or positive behaviors. However, each of these methods are relatively limited in scale and resource intensive. A survey could provide a relatively low-cost approach to systematically gather this information on a larger scale. The primary purpose of the research was to develop and assess a surveys methodology for assessing crews' activities in normal flights and the operational perturbations encountered during normal operations. We hope that such a survey could be both a research tool as well as a safety management aid for the aviation industry. We collected responses concerning revenue flights from two groups of airline pilots (N = 25 & N= 65). The results indicated that relatively few flights proceeded exactly as in the original flight plan. Pilots routinely anticipated and adapted to changing circumstances. We will review the challenges encountered in developing the survey and summarize preliminary findings from two administrations of the survey to airline pilots.

human contribution safety↗