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At least 901 records · Page 50

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NASA NTRS1993

Design, analysis, and control of large transport aircraft utilizing engine thrust as a backup system for the primary flight controls

A review of accidents that involved the loss of hydraulic flight control systems serves as an introduction to this project. In each of the accidents--involving transport aircraft such as the DC-10, the C-5A, the L-1011, and the Boeing 747--the flight crew attempted to control the aircraft by means of thrust control. Although these incidents had tragic endings, in the absence of control power due to primary control system failure, control power generated by selective application of engine thrust has proven to be a viable alternative. NASA Dryden has demonstrated the feasibility of controlling an aircraft during level flight, approach, and landing conditions using an augmented throttles-only control system. This system has been successfully flown in the flight test simulator for the B-720 passenger transport and the F-15 air superiority fighter and in actual flight tests for the F-15 aircraft. The Douglas Aircraft Company is developing a similar system for the MD-11 aircraft. The project's ultimate goal is to provide data for the development of thrust control systems for mega-transports (600+ passengers).

Gerren, Donna S.↗

NASA NTRS1991

Conduct and results of the Interagency Nuclear Safety Review Panel's evaluation of the Ulysses space mission

After over a year of detailed independent review, a Safety Evaluation Report (SER) was prepared for the nuclear-powered Ulysses spacecraft mission. An overview is presently given of the Ulysses mission as well as the conduct and results of the evaluation process; in the final analysis, the SER was supportive of a positive launch decision. Eleven key accident scenarios were carried through to complete analysis, out of a total of 19 possible accidents involving a potential for fuel release to the spacecraft environment.

Sholtis, Joseph A., Jr.↗

NASA NTRS1953

Accelerations and Passenger Harness Loads Measured in Full-Scale Light-Airplane Crashes

Full-scale light-airplane crashes simulating stall-spin accidents were conducted to determine the decelerations to which occupants are exposed and the resulting harness forces encountered in this type of accident. Crashes at impact speeds from 42 to 60 miles per hour were studied. The airplanes used were of the familiar steel-tube, fabric-covered, tandem, two-seat type. In crashes up to an impact speed of 60 miles per hour, crumpling of the forward fuselage structure prevented the maximum deceleration at the rear-seat location from exceeding 26 to 33g. This maximum g value appeared independent of the impact speed. Restraining forces in the seatbelt - shoulder-harness combination reached 5800 pounds. The rear-seat occupant can survive crashes of the type studied at impact speeds up to 60 miles per hour, if body movement is restrained by an adequate seatbelt-shoulder-harness combination so as to prevent injurious contact with obstacles normally present in the cabin. Inwardly collapsing cabin structure, however, is a potential hazard in the higher-speed crashes.

Eiband, A. Martin↗

NASA NTRS1937

Aircraft accidents.method of analysis

This report is a revision of NACA-TR-357. It was prepared by the Committee on Aircraft Accidents. The purpose of this report is to provide a basis for the classification and comparison of aircraft accidents, both civil and military.

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NASA NTRS1994

Shuttle 51L: Challenger

This video follows the pre-launch and launch of the Space Shuttle Challenger preceding the accident. It then details the accident investigation report.

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NASA NTRS1992

Review of performance, medical, and operational data on pilot aging issues

An extensive review of the literature and studies relating to performance, medical, operational, and legal data regarding pilot aging issues was performed in order to determine what evidence there is, if any, to support mandatory pilot retirement. Popular misconceptions about aging, including the failure to distinguish between the normal aging process and disease processes that occur more frequently in older individuals, continue to contribute to much of the misunderstanding and controversy that surround this issue. Results: Review of medical data related to the pilot aging issue indicate that recent improvement in medical diagnostics and treatment technology have made it possible to identify to a high degree individuals who are at risk for developing sudden incapacitating illness and for treating those with disqualifying medical conditions. Performance studies revealed that after controlling for the presence of disease states, older pilots are able to perform as well as younger pilots on many performance tasks. Review of accident data showed that older, healthy pilots do not have higher accident rates than younger pilots, and indeeed, evidence suggests that older pilots have an advantage in the cockpit due to higher experience levels. The Man-Machine-Mission-Environment interface of factors can be managed through structured, supervised, and enhanced operations, maintenance, flight reviews, and safety procedures in order to ensure safe and productive operations by reducing the margin of error and by increasing the margin of safety. Conclusions: There is no evidence indicating any specific age as an arbitrary cut-off point for pilots to perform their fight duties. A combination of regular medical screening, performance evaluation, enhanced operational maintenance, and safety procedures can most effectively ensure a safe pilot population than can a mandatory retirement policy based on arbitrary age restrictions.

Stoklosa, J. H.↗

NASA NTRS1994

Advanced automated glass cockpit certification: Being wary of human factors

This paper presents some facets of the French experience with human factors in the process of certification of advanced automated cockpits. Three types of difficulties are described: first, the difficulties concerning the hotly debated concept of human error and its non-linear relationship to risk of accident; a typology of errors to be taken into account in the certification process is put forward to respond to this issue. Next, the difficulties connected to the basically gradual and evolving nature of pilot expertise on a given type of aircraft, which contrasts with the immediate and definitive style of certifying systems. The last difficulties to be considered are those related to the goals of certification itself on these new aircraft and the status of findings from human factor analyses (in particular, what should be done with disappointing results, how much can the changes induced by human factors investigation economically affect aircraft design, how many errors do we need to accumulate before we revise the system, what should be remedied when human factor problems are discovered at the certification stage: the machine? pilot training? the rules? or everything?). The growth of advanced-automated glass cockpits has forced the international aeronautical community to pay more attention to human factors during the design phase, the certification phase and pilot training. The recent creation of a human factor desk at the DGAC-SFACT (Official French services) is a direct consequence of this. The paper is divided into three parts. Part one debates human error and its relationship with system design and accident risk. Part two describes difficulties connected to the basically gradual and evolving nature of pilot expertise on a given type of aircraft, which contrasts with the immediate and definitive style of certifying systems. Part three focuses on concrete outcomes of human factors for certification purposes.

Amalberti, Rene↗

NASA NTRS1993

Automation design and crew coordination

Advances in technology have greatly impacted the appearance of the modern aircraft cockpit. Where once one would see rows upon rows. The introduction of automation has greatly altered the demands on the pilots and the dynamics of aircrew task performance. While engineers and designers continue to implement the latest technological innovations in the cockpit - claiming higher reliability and decreased workload - a large percentage of aircraft accidents are still attributed to human error. Rather than being the main instigators of accidents, operators tend to be the inheritors of system defects created by poor design, incorrect installation, faulty maintenance and bad management decisions. This paper looks at some of the variables that need to be considered if we are to eliminate at least one of these inheritances - poor design. Specifically, this paper describes the first part of a comprehensive study aimed at identifying the effects of automation on crew coordination.

Segal, Leon D.↗

NASA NTRS1993

Emergency medical service (EMS): A unique flight environment

The EMS flight environment is unique in today's aviation. The pilots must respond quickly to emergency events and often fly to landing zones where they have never been before . The time from initially receiving a call to being airborne can be as little as two to three minutes. Often the EMS pilot is the only aviation professional on site, they have no operations people or other pilots to aid them in making decisons. Further, since they are often flying to accident scenes, not airports, there is often complete weather and condition information. Therefore, the initial decision that the pilot must make, accepting or declining a flight, can become very difficult. The accident rate of EMS helicopters has been relatively high over the past years. NASA-Ames research center has taken several steps in an attempt to aid EMS pilots in their decision making and situational awareness. A preflight risk assessment system (SAFE) was developed to aid pilots in their decision making, and was tested at an EMS service. The resutls of the study were promising and a second version incorporating the lessons learned is under development. A second line of research was the development of a low cost electronic chart display (ECD). This is a digital map display to help pilots maintain geographical orientation. Another thrust was undertaken in conjunction with the Aviation Safety Reporting System (ASRS). This involved publicizing the ASRS to EMS pilots and personnel, and calling each of the reporters back to gather additional information. This paper will discuss these efforts and how they may positively impact the safety of EMS operations.

Shively, R. Jay↗

NASA NTRS1996

Loss of Situation Awareness in Pilots: Analysis of Incident Reports

Approximately 75% of all aviation accidents and incidents are attributable to human failures in monitoring, managing, and operating system. Tactical decision errors were found to be a factor in 25 of 37 major US air transport accidents between 1978 and 1990. These two facts demonstrate the inability of some pilots to maintain situation awareness. Situation awareness (SA) is defined as 'the perception of elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future". Thus, when a pilot loses SA, he or she is unable to ether perceive, comprehend, or project the status of the aircraft. In pilots terms, he or she has 'fallen behind the airplane'. Our study this summer involved an analysis of 190 NASA Aviation Safety Reporting System (ASRS) reports.

Eric B. Villeda↗

NASA NTRS1997

Piloted Simulation Tests of Propulsion Control as Backup to Loss of Primary Flight Controls for a B747-400 Jet Transport

Partial failures of aircraft primary flight control systems and structural damages to aircraft during flight have led to catastrophic accidents with subsequent loss of lives (e.g. DC-10, B-747, C-5, B-52, and others). Following the DC-10 accident at Sioux City, Iowa in 1989, the National Transportation Safety Board recommended 'Encourage research and development of backup flight control systems for newly certified wide-body airplanes that utilize an alternate source of motive power separate from that source used for the conventional control system.' This report describes the concept of a propulsion controlled aircraft (PCA), discusses pilot controls, displays, and procedures; and presents the results of a PCA piloted simulation test and evaluation of the B747-400 airplane conducted at NASA Ames Research Center in December, 1996. The purpose of the test was to develop and evaluate propulsion control throughout the full flight envelope of the B747-400 including worst case scenarios of engine failures and out of trim moments. Pilot ratings of PCA performance ranged from adequate to satisfactory. PCA performed well in unusual attitude recoveries at 35,000 ft altitude, performed well in fully coupled ILS approaches, performed well in single engine failures, and performed well at aft cg. PCA performance was primarily limited by out-of-trim moments.

Bull, John↗

NASA NTRS1997

A Probability-Base Alerting Logic for Aircraft on Parallel Approach

This document discusses the development and evaluation of an airborne collision alerting logic for aircraft on closely-spaced approaches to parallel runways. A novel methodology is used when links alerts to collision probabilities: alerting thresholds are set such that when the probability of a collision exceeds an acceptable hazard level an alert is issued. The logic was designed to limit the hazard level to that estimated for the Precision Runway Monitoring system: one accident in every one thousand blunders which trigger alerts. When the aircraft were constrained to be coaltitude, evaluations of a two-dimensional version of the alerting logic show that the achieved hazard level is approximately one accident in every 250 blunders. Problematic scenarios have been identified and corrections to the logic can be made. The evaluations also show that over eighty percent of all unnecessary alerts were issued during scenarios in which the miss distance would have been less than 1000 ft, indicating that the alerts may have been justified. Also, no unnecessary alerts were generated during normal approaches.

Carpenter, Brenda D.↗

NASA NTRS1997

NASA and Ethics: Training and Practice

This paper is about the National Aeronautics and Space Administration(NASA) and the practice of professional ethics. It has been eleven years(Jan. 28, 1986) since the Challenger accident and the past decade has been a time of investigation, assessment, and finger-pointing, as well as a time for introspection and internal reform. While there has been a lot of rhetoric about ethical commitments at NASA, there has also been a dearth of empirically-based knowledge about what NASA and its various contractors are doing about professional ethics and what decisionmaking criteria are being used. It has been a decade of cost-cutting and personnel cut-backs. One has to wonder what, in all this time, NASA has done to create an ethical climate in which events like the Challenger accident are less likely to happen. In the fall of 1995, as part of competition for a mini-grant from NASA, a request for funding to complete an ethical profile of the agency was submitted. This papeR contributes to knowledge about NASA and ethics by reporting on the results of the first year of research which was spent in doing a comprehensive literature and web-site review along with phone interviews and e-mail correspondence with NASA ethics officers. The goal of this first year was to see what ethics activity has been documented and to ascertain what work is being done to raise the ethical question with NASA. Questions for which answers were sought include: (1) What is NASA now doing regarding ethics?; (2) What training is being provided? By whom? For whom?; (3) Are the answers to these questions different at different NASA installations?

Bruce, Willa Marie↗

NASA NTRS1999

An Overview of Landing Gear Dynamics

One of the problems facing the aircraft community is landing gear dynamics, especially shimmy and brake-induced vibration. Although neither shimmy nor brake-induced vibrations are usually catastrophic, they can lead to accidents due to excessive wear and shortened life of gear parts and contribute to pilot and passenger discomfort. Recently, NASA has initiated an effort to increase the safety of air travel by reducing the number of accidents by a factor of five in ten years. This safety initiative has spurred an increased interest in improving landing gear design to minimize shimmy and brake-induced vibration that are still largely misunderstood phenomena. In order to increase the understanding of these problems, a literature survey was performed. The major focus of the paper is to summarize work documented from the last ten years to highlight the latest efforts in solving these vibration problems. Older publications are included to understand the longevity of the problem and the findings from earlier researchers. The literature survey revealed a variety of analyses, testing, modeling, and simulation of aircraft landing gear. Experimental validation and characterization of shimmy and brake-induced vibration of aircraft landing gear are also reported. This paper presents an overview of the problem documented in the references together with a history of landing gear dynamic problems and solutions. Based on the assessment of this survey, recommendations of the most critically needed enhancements to the state of the art are given.

Pritchard, Jocelyn↗

NASA NTRS1997

Environmental Impact Statement for the Cassini Mission

This Final Supplemental Environmental Impact Statement (FSEIS) to the 1995 Cassini mission Environmental Impact Statement (EIS) focuses on information recently made available from updated mission safety analyses. This information is pertinent to the consequence and risk analyses of potential accidents during the launch and cruise phases of the mission that were addressed in the EIS. The type of accidents evaluated are those which could potentially result in a release of plutonium dioxide from the three Radioisotope Thermoelectric Generators (RTGS) and the up to 129 Radioisotope Heater Units (RHUS) onboard the Cassini spacecraft. The RTGs use the heat of decay of plutonium dioxide to generate electric power for the spacecraft and instruments. The RHUs, each of which contains a small amount of plutonium dioxide, provide heat for controlling the thermal environment of the spacecraft and several of its instruments. The planned Cassini mission is an international cooperative effort of the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Italian Space Agency (ASI) to conduct a 4-year scientific exploration of the planet Saturn, its atmosphere, moons, rings, and magnetosphere.

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NASA NTRS1999

An Overview of Landing Gear Dynamics

Pritchard, Jocelyn I.↗

NASA NTRS1988

STS-26 Preflight Press Briefing: Flight Crew and TDRS

This NASA KSC video release presents part of a press conference held prior to Discovery flight STS-26, the first shuttle mission flown following the 51-L Challenger accident. The first portion of the video presents the 5 member flight crew, (Frederick H. Hauck, Commander, Richard O. Covey, Pilot, John M. Lounge, Mission Specialist, George D. Nelson, Mission Specialist, and David C. Hilmers, Mission Specialist) answering questions posed by scientific journalists. Inquiries are made regarding the approximately 250 changes implemented on the orbiter and boosters, failures that occurred during 51-L, astronaut attitudes about flying the first mission since the Challenger accident, and the issue of range safety. The second part of the video includes viewgraph presentations given by Dr. Dale W. Harris (TDRS Project Manager, Goddard Space Flight Center(GSFC)) and Gary A. Morse (Network Director, GSFC) that discuss the primary payload, the NASA Tracking and Data Relay Satellite-3 (TDRS-3) that is attached to an Inertial Upper Stage (IUS), and is the second TDRS deployed.

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NASA NTRS1988

STS-26 Preflight Press Briefing: 5 Man Crew

This NASA KSC video release presents part of a press conference held prior to Discovery flight STS-26, the first shuttle mission flown following the 51-L Challenger accident. The video opens with a statement from Commander Frederick H. Hauck, and the introductions of crew members, Richard O. Covey, Pilot, and mission specialists, John M. Lounge, George D. Nelson, and David C. Hilmers. Some of the questions posed by scientific journalists addressed the following subjects: launch preparation in the month prior to flight, astronaut family anxieties in light of the Challenger accident, extent of safety measures made prior to flight, flight readiness firing, the crew escape system, civilians in space, conservative mission design, astronaut selection, mission turnaround and launch rate, and the ability to maintain a high level of scrutiny regarding safety on future missions.

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