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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

A Cognitive-System Model for En Route Air Traffic Management

NASA Ames Research Center has been engaged in the development of advanced air traffic management technologies whose basic form is cognitive aiding systems for air traffic controller and flight deck operations. In the design and evaluation of such systems the dynamic interaction between the airborne aiding system and the ground-based aiding systems forms a critical coupling for control. The human operator is an integral control element in the system and the optimal integration of human decision and performance parameters with those of the automation aiding systems offers a significant challenge to cognitive engineering. This paper presents a study in full mission simulation and the development of a predictive computational model of human performance. We have found that this combination of methodologies provide a powerful design-aiding process. We have extended the computational model Man Machine Integrated Design and Analysis System (N13DAS) to include representation of multiple cognitive agents (both human operators and intelligent aiding systems), operating aircraft airline operations centers and air traffic control centers in the evolving airspace. The demands of this application require the representation of many intelligent agents sharing world-models, and coordinating action/intention with cooperative scheduling of goals and actions in a potentially unpredictable world of operations. The operator's activity structures have been developed to include prioritization and interruption of multiple parallel activities among multiple operators, to provide for anticipation (knowledge of the intention and action of remote operators), and to respond to failures of the system and other operators in the system in situation-specific paradigms. We have exercised this model in a multi-air traffic sector scenario with potential conflict among aircraft at and across sector boundaries. We have modeled the control situation as a multiple closed loop system. The inner and outer loop alerting structure of air traffic management has many implications that need to be investigated to assure adequate design. First, there are control and stability factors implicit in the design. As the inner loop response time approaches that of the outer loop, system stability may be compromised in that controllers may be solving a problem the nature of which has already been changed by pilot action. Second, information exchange and information presentation for both air and ground must be designed to complement as opposed to compete with each other. Third, the level of individual and shared awareness in trajectory modification and flight conformance needs to be defined. Fourth, the level of required awareness and performance impact of mixed fleet operations and failed-mode recovery must be explored.

Corker, Kevin M.↗
NASA NTRS1972

A flight evaluation of curved landing approaches

The development of STOL technology for application to operational short-haul aircraft is accompanied by the requirement for solving problems in many areas. One of the most obvious problems is STOL aircraft operations in the terminal area. The increased number of terminal operations needed for an economically viable STOL system as compared with the current CTOL system and the incompatibility of STOL and CTOL aircraft speeds are positive indicators of an imminent problem. The high cost of aircraft operations, noise pollution, and poor short-haul service are areas that need improvement. A potential solution to some of the operational problems lies in the capability of making curved landing approaches under both visual and instrument flight conditions.

Gee, S. W.↗
NASA NTRS1974

Performance of a model cascade thrust reverser for short-haul applications

Aerodynamic and acoustic characteristics are presented for a cowlmounted, model cascade thrust reverser suitable for short-haul aircraft. Thrust reverser efficiency and the influence on fan performance were determined from isolated fan-driven models under static and forward velocity conditions. Cascade reverser noise characteristics were determined statically in an isolated pipe-flow test, while aerodynamic installation effects were determined with a wind-tunnel, fan-powered airplane model. Application of test results to short-haul aircraft calculations demonstrated that such a cascade thrust reverser may be able to meet both the performance and noise requirements for short-haul aircraft operation. However, aircraft installation effects can be quite significant.

Dietrich, D. A.↗
NASA NTRS1974

Performance of a model cascade thrust reverser for short-haul applications

Aerodynamic and acoustic characteristics are presented for a cowl-mounted, model cascade thrust reverser suitable for short-haul aircraft. Thrust reverser efficiency and the influence on fan performance were determined from isolated fan-driven models under static and forward velocity conditions. Cascade reverser noise characteristics were determined statically in an isolated pipe-flow test, while aerodynamic installation effects were determined with a wind-tunnel, fan-powered airplane model. Application of test results to short-haul aircraft calculations demonstrate that such a cascade thrust reverser may be able to meet both the performance and noise requirements for short-haul aircraft operation. However, aircraft installation effects can be quite significant.

Dietrich, D. A.↗
NASA NTRS2016

Safely Enabling Low-Altitude UAS Operations: Unmanned Aircraft System Traffic Management

Concept of operations; Roles, responsibilities, implications on who pays; Information architecture paved way for FAA's (Federal Aviation Administration's) RFI (Request for Information); Demonstrated initial feasibility of architecture, application-protocol-interface-based approach, and overall construct; Data exchange and protocols; Demonstration of UTM (Unmanned Aerial Systems Traffic Management) TCL1 (Tuscaloosa, AL Airport Terminal 1) with all 6 test sites; Initial demonstration of UTM TCL2 for BVLOS (Beyond Visual Line-of-Sight) requirements.

Low-altitude UTM↗
NASA NTRS2019

CNS Simulation Tool Development for Increasingly Complex Airspace Operation Evaluation

As unmanned aircraft operations continue to grow and new vehicles such as air taxi, supersonic aircraft and high-altitude long endurance aircraft seek access to the airspace, it is anticipated that National Airspace System (NAS) operations will increase in density and complexity. To manage the influx, demand and safe integration of these new aircraft and missions into the NAS, a careful evaluation of existing and new operational concepts, vehicle characteristics and technology performance is required. Communications, Navigation and Surveillance (CNS) technologies operating in the NAS have evolved to meet changing needs of the Air Traffic Control System and the vehicles operating in the airspace. Today's CNS systems have been architected to deliver critical services to a carefully designed airspace configuration and to serve airborne vehicles equipped with standardized systems that enable global air navigation. The introduction of new vehicles is projected to expand NAS operations beyond today's configuration to include a new breed of aircraft operating from non-conventional aerodromes, resulting in a mix of vehicles operating in the same airspace. To enable this expansion, it is anticipated that modeling and simulation will play an important role in the evaluation of new management concept of operations.In this regard, NASA is developing simulation capabilities that will enable the evaluation of new concepts of operation and CNS technology performance in an increasingly dense, high-tempo operational environment. The NASA Glenn Research Center is working on the development of CNS simulation capabilities intended to support the integrated evaluation of operational concepts and emerging technologies. This presentation describes simulation capability development efforts that, together with other simulation tools, will enable evaluation of new concepts and technologies for the integration of new vehicles and services into the NAS. [Also discussed: NASA Shadow Mode Assessment using Realistic Technologies for the National Airspace System (SMART NAS)]

Surveillance↗
NASA NTRS2002

Search and Rescue Operations of Aircraft in Africa: Some Compelling Issues

The world aviation community has felt the compelling need for a well-coordinated global programme for search and rescue operations of aircraft ever since commercial aviation was regulated in 1944. Guidelines and plans of action for search and rescue have therefore been considered critical in the event of an aircraft accident. This fact is eminently brought to bear in the continental regions of Africa and South America in particular, where vast expanses of land are still uninhabited or sparsely populated and controlled flight into terrain (CFIT-where an aircraft may crash on land while still under the control of technical crew) is a common occurrence. There are numerous guidelines that have been adopted under the umbrella of the International Civil Aviation Organization which are already in place for the provision of search and rescue operations pertaining to aircraft. However, when an accident occurs in the territory of a State, there are sensitivities involving the State in which the aircraft concerned was registered and issues of sovereignty which have to be considered. Additionally. issues such as the voluntary nature of the search and rescue services offered. confidentiality, timeliness of such operations, fairness and uniformity all play a critical role. This article addresses the issue of search and rescue operations in Africa and examines in some detail where the world aviation community is right now and where it is headed in this important field of human endeavour.

Abeyratne, Ruwantissa I. R.↗
NASA NTRS2006

A Simulation Based Approach for Contingency Planning for Aircraft Turnaround Operation System Activities in Airline Hubs

Commercial aircraft undergo a significant number of maintenance and logistical activities during the turnaround operation at the departure gate. By analyzing the sequencing of these activities, more effective turnaround contingency plans may be developed for logistical and maintenance disruptions. Turnaround contingency plans are particularly important as any kind of delay in a hub based system may cascade into further delays with subsequent connections. The contingency sequencing of the maintenance and logistical turnaround activities were analyzed using a combined network and computer simulation modeling approach. Experimental analysis of both current and alternative policies provides a framework to aid in more effective tactical decision making.

Adeleye, Sanya↗
NASA NTRS2011

Implementation of Enhanced Propulsion Control Modes for Emergency Flight Operation

Aircraft engines can be effective actuators to help pilots avert or recover from emergency situations. Emergency control modes are being developed to enhance the engines performance to increase the probability of recovery under these circumstances. This paper discusses a proposed implementation of an architecture that requests emergency propulsion control modes, allowing the engines to deliver additional performance in emergency situations while still ensuring a specified safety level. In order to determine the appropriate level of engine performance enhancement, information regarding the current emergency scenario (including severity) and current engine health must be known. This enables the engine to operate beyond its nominal range while minimizing overall risk to the aircraft. In this architecture, the flight controller is responsible for determining the severity of the event and the level of engine risk that is acceptable, while the engine controller is responsible for delivering the desired performance within the specified risk range. A control mode selector specifies an appropriate situation-specific enhanced mode, which the engine controller then implements. The enhanced control modes described in this paper provide additional engine thrust or response capabilities through the modification of gains, limits, and the control algorithm, but increase the risk of engine failure. The modifications made to the engine controller to enable the use of the enhanced control modes are described, as are the interaction between the various subsystems and importantly, the interaction between the flight controller/pilot and the propulsion control system. Simulation results demonstrate how the system responds to requests for enhanced operation and the corresponding increase in performance.

Csank, Jeffrey T.↗
NASA NTRS1986

NASA/JPL aircraft SAR operations for 1984 and 1985

The NASA/JPL aircraft synthetic aperture radar (SAR) was used to conduct major data acquisition expeditions in 1983 through 1985. Substantial improvements to the aircraft SAR were incorporated in 1981 through 1984 resulting in an imaging radar that could simultaneously record all four combinations of linear horizontal and vertical polarization (HH, HV, VH, VV) using computer control of the radar logic, gain setting, and other functions. Data were recorded on high-density digital tapes and processed on a general-purpose computer to produce 10-km square images with 10-m resolution. These digital images yield both the amplitude and phase of the four polarizations. All of the digital images produced so far are archived at the JPL Radar Data Center and are accessible via the Reference Notebook System of that facility. Sites observed in 1984 and 1985 included geological targets in the western United States, as well as agricultural and forestry sites in the Midwest and along the eastern coast. This aircraft radar was destroyed in the CV-990 fire at March Air Force Base on 17 July 1985. It is being rebuilt for flights in l987 and will likely be operated in a mode similar to that described here. The data from 1984 and 1985 as well as those from future expeditions in 1987 and beyond will provide users with a valuable data base for the multifrequency, multipolarization Spaceborne Imaging Radar (SIR-C) scheduled for orbital operations in the early 1990's.

Thompson, T. W.↗
NASA NTRS2017

Simulation Evaluation of Pilot Inputs for Real Time Modeling During Commercial Flight Operations

Aircraft dynamics characteristics can only be identified from flight data when the aircraft dynamics are excited sufficiently. A preliminary study was conducted into what types and levels of manual piloted control excitation would be required for accurate Real-Time Parameter IDentification (RTPID) results by commercial airline pilots. This includes assessing the practicality for the pilot to provide this excitation when cued, and to further understand if pilot inputs during various phases of flight provide sufficient excitation naturally. An operationally representative task was evaluated by 5 commercial airline pilots using the NASA Ice Contamination Effects Flight Training Device (ICEFTD). Results showed that it is practical to use manual pilot inputs only as a means of achieving good RTPID in all phases of flight and in flight turbulence conditions. All pilots were effective in satisfying excitation requirements when cued. Much of the time, cueing was not even necessary, as just performing the required task provided enough excitation for accurate RTPID estimation. Pilot opinion surveys reported that the additional control inputs required when prompted by the excitation cueing were easy to make, quickly mastered, and required minimal training.

Martos, Borja↗
NASA NTRS1947

Effects of Induction-System Icing on Aircraft-Engine Operating Characteristics

An investigation was conducted on a multicylinder aircraft engine on a dynamometer stand to determine the effect of induction-system icing on engine operating characteristics and to compare the results with those of a previous laboratory investigation in which only the carburetor and the engine-stage supercharger assembly from the engine were used. The experiments were conducted at simulated glide power, low cruise power, and normal rated power through a range of humidity ratios and air temperatures at approximately sea-level pressure. Induction-system icing was found to occur within approximately the same limits as those established by the previous laboratory investigation after making suitable allowances for the difference in fuel volatility and throttle angles. Rough operation of the engine was experienced when ice caused a marked reduction in the air flow. Photographs of typical ice formations from this investigation indicate close similarity to icing previously observed in the laboratory.

Stevens, Howard C., Jr.↗
NASA NTRSDate not supplied

Impact of Latency and Reliability on Separation Assurance with Remotely Piloted Aircraft in Terminal Operations

Remotely Piloted Aircraft (RPA) for cargo operations in the national airspace system will impact safety due to, among other factors, the latency and reliability of command & control, and of communication. This paper investigates the safety impact with increasing mix of RPA amidst manned traffic in a generic arrival pattern with three merging flows. Latency was modelled as the response time between air traffic control's determination of a resolution and the RPAs' initiation of the maneuver. Reliability was modelled as a message drop probability. The experiment was repeated with two different aircraft types having different performance characteristics as representatives of RPA for conducting automated cargo operations. Overall response time above thirty seconds and message drop probability over twenty percent caused losses of separation. Specific results depended on the RPA aircraft type. The detailed impacts of latency and reliability with increasing mix of RPA traffic are provided. Applications of the approach for further studies at increasing levels of automation are also discussed.

Vishwanath Bulusu↗
NASA NTRS2022

Impact of Latency and Reliability on Separation Assurance with Remotely Piloted Aircraft in Terminal Operations

Remotely Piloted Aircraft (RPA) for cargo operations in the national airspace system will impact safety due to, among other factors, the latency and reliability of command & control, and of communication. This paper investigates the safety impact with increasing mix of RPA amidst manned traffic in a generic arrival pattern with three merging flows. Latency was modelled as the response time between air traffic control's determination of a resolution and the RPAs' initiation of the maneuver. Reliability was modelled as a message drop probability. The experiment was repeated with two different aircraft types having different performance characteristics as representatives of RPA for conducting automated cargo operations. Overall response time above thirty seconds and message drop probability over twenty percent caused losses of separation. Specific results depended on the RPA aircraft type. The detailed impacts of latency and reliability with increasing mix of RPA traffic are provided. Applications of the approach for further studies at increasing levels of automation are also discussed.

Vishwanath Bulusu↗
NASA NTRS2007

Design and Testing of an Unlimited Field-of-regard Synthetic Vision Head-worn Display for Commercial Aircraft Surface Operations

Experiments and flight tests have shown that a Head-Up Display (HUD) and a head-down, electronic moving map (EMM) can be enhanced with Synthetic Vision for airport surface operations. While great success in ground operations was demonstrated with a HUD, the research noted that two major HUD limitations during ground operations were their monochrome form and limited, fixed field of regard. A potential solution to these limitations found with HUDs may be emerging Head Worn Displays (HWDs). HWDs are small, lightweight full color display devices that may be worn without significant encumbrance to the user. By coupling the HWD with a head tracker, unlimited field-of-regard may be realized for commercial aviation applications. In the proposed paper, the results of two ground simulation experiments conducted at NASA Langley are summarized. The experiments evaluated the efficacy of head-worn display applications of Synthetic Vision and Enhanced Vision technology to enhance transport aircraft surface operations. The two studies tested a combined six display concepts: (1) paper charts with existing cockpit displays, (2) baseline consisting of existing cockpit displays including a Class III electronic flight bag display of the airport surface; (3) an advanced baseline that also included displayed traffic and routing information, (4) a modified version of a HUD and EMM display demonstrated in previous research; (5) an unlimited field-of-regard, full color, head-tracked HWD with a conformal 3-D synthetic vision surface view; and (6) a fully integrated HWD concept. The fully integrated HWD concept is a head-tracked, color, unlimited field-of-regard concept that provides a 3-D conformal synthetic view of the airport surface integrated with advanced taxi route clearance, taxi precision guidance, and data-link capability. The results of the experiments showed that the fully integrated HWD provided greater path performance compared to using paper charts alone. Further, when comparing the HWD with the HUD concept, there were no differences in path performance. In addition, the HWD and HUD concepts were rated via paired-comparisons the same in terms of situational awareness and workload. However, there were over twice as many taxi incursion events with the HUD than the HWD.

Arthur, Jarvis J., III↗
NASA NTRS1982

Continued research on selected parameters to minimize community annoyance from airport noise

A mathematical model of the annoyance created at an airport by aircraft operations is developed. The model incorporates population distribution considerations around an airport and the annoyance caused by aircraft noise. The objective function of this model corresponds to seeking to minimize total population annoyance created by all aircraft operations in a 24-hour period. Several factors are included in this model as constraint bounded. Demand for flight services is incorporated by including lower bounds on the number of operations by type of aircraft, runway used and time period. Also upper bounds on the number of operations for each runway are included. The mathematical model as formulated is recognized as corresponding to a nonlinear integer mathematical programming problem.

Frair, L.↗