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At least 127 records · Page 7

Flight Deck Design of a Hybrid Turbine/Electric Passenger Aircraft

NASA is exploring the development of a 180-passenger subsonic single engine aft turbine aircraft, The aft turbine provides electric power in a hybrid design to wing mounted electric engines, creating a highly efficient, high-bypass-ratio fan equivalent. The SUbsonic Single Aft eNgine (SUSAN) aircraft is being developed as a sustainable subsonic regional aircraft that seeks to reduce emission levels by 50% in the next few decades. Pilot-in-the-loop studies were conducted at the NASA Langley Research Center in Hampton, Virginia, to explore the flight deck design for the hybrid electric aircraft. Following modern trends in commercial aircraft flight decks with full time augmented controls and a quiet and dark philosophy, single throttle and simplified engine displays were developed for the SUSAN aircraft. The aircraft includes a single aft mounted turbine engine and 16 wing mounted electric fans. The final design was developed from feedback received during an earlier pilot-in-the-loop study where one, two, and three throttles were tested in standard airline operations, including various failures of the turbine and electric engines. Current flight deck designs normally provide control inceptors for each propulsion engine and an engine display for all primary aircraft engine parameters. With full time augmentation expected, a single throttle control with autothrottle always engaged, even during failures, is desired. Augmentation of flight controls using distributed thrust also requires full time control of the electric engines using automation. Additionally, electric engine thrust is augmented during climb based on battery state of charge. Thrust augmentation changes faster than human reaction time and therefore requires full-time automation. A pilot-in-the-loop study was conducted at the NASA Langley Research Center in Hampton, Virginia, to test the final design of the single throttle with simplified engine displays. Fourteen airline pilots evaluated the single throttle and engine display concept. Electric engine failures included one, four symmetric, and eight non-symmetric electric engine failures. The turbine engine was evaluated for complete and partial failure during critical phases of flight to include takeoff as well as enroute. Unexpected go-arounds increase workload and require significant throttle manipulation. Go-arounds were included to ensure the single throttle was usable for all phases of flight. Failures during takeoff required a return to the departure field and failures enroute required a diversion except for one and four electric engine failures as these failures did not affect aircraft flyability or range. There are currently no Part 25 aircraft certified with hybrid systems or electric engines with batteries as emergency propulsion. For turbine engine failures in the SUSAN aircraft design, range is limited to 30 minutes at full power. Battery state of charge and battery health displays were developed and tested for usability and to determine how well they supported pilot decisions for alternate airports during emergency diversions. Novel displays using shape and color were developed to provide immediate feedback when state of charge became critical. This paper details the pilot study including pilot feedback supporting the potential for increased automation and a single throttle control. Detailed recommendations are provided for a novel single throttle control and additional pilot controls to support selection of engines during start, shutdown, and engine troubleshooting procedures. This design deviates significantly from current practice of providing throttles for each propulsion engine. Engine display recommendations are provided based on pilot feedback during a guided post-evaluation interview. Battery state of charge and battery health display recommendations were collected from all airline crews. The simplified engine displays design was rated excellent as measured with a usability scale. Quantitative metrics include airspeed tracking, time to complete checklists, time to make diversion decisions and the quality of the diversion decision. Recommendations for future studies are documented with supporting research and current observations about upcoming flight deck certifications.

autothrottle↗

Flight Deck Design of a Hybrid Turbine/Electric Passenger Aircraft

NASA is exploring the development of a 180-passenger subsonic single engine aft turbine aircraft, The aft turbine provides electric power in a hybrid design to wing mounted electric engines, creating a highly efficient, high-bypass-ratio fan equivalent. The SUbsonic Single Aft eNgine (SUSAN) aircraft is being developed as a sustainable subsonic regional aircraft that seeks to reduce emission levels by 50% in the next few decades. Pilot-in-the-loop studies were conducted at the NASA Langley Research Center in Hampton, Virginia, to explore the flight deck design for the hybrid electric aircraft. Following modern trends in commercial aircraft flight decks with full time augmented controls and a quiet and dark philosophy, single throttle and simplified engine displays were developed for the SUSAN aircraft. The aircraft includes a single aft mounted turbine engine and 16 wing mounted electric fans. The final design was developed from feedback received during an earlier pilot-in-the-loop study where one, two, and three throttles were tested in standard airline operations, including various failures of the turbine and electric engines. Current flight deck designs normally provide control inceptors for each propulsion engine and an engine display for all primary aircraft engine parameters. With full time augmentation expected, a single throttle control with autothrottle always engaged, even during failures, is desired. Augmentation of flight controls using distributed thrust also requires full time control of the electric engines using automation. Additionally, electric engine thrust is augmented during climb based on battery state of charge. Thrust augmentation changes faster than human reaction time and therefore requires full-time automation. A pilot-in-the-loop study was conducted at the NASA Langley Research Center in Hampton, Virginia, to test the final design of the single throttle with simplified engine displays. Fourteen airline pilots evaluated the single throttle and engine display concept. Electric engine failures included one, four symmetric, and eight non-symmetric electric engine failures. The turbine engine was evaluated for complete and partial failure during critical phases of flight to include takeoff as well as enroute. Unexpected go-arounds increase workload and require significant throttle manipulation. Go-arounds were included to ensure the single throttle was usable for all phases of flight. Failures during takeoff required a return to the departure field and failures enroute required a diversion except for one and four electric engine failures as these failures did not affect aircraft flyability or range. There are currently no Part 25 aircraft certified with hybrid systems or electric engines with batteries as emergency propulsion. For turbine engine failures in the SUSAN aircraft design, range is limited to 30 minutes at full power. Battery state of charge and battery health displays were developed and tested for usability and to determine how well they supported pilot decisions for alternate airports during emergency diversions. Novel displays using shape and color were developed to provide immediate feedback when state of charge became critical. This paper details the pilot study including pilot feedback supporting the potential for increased automation and a single throttle control. Detailed recommendations are provided for a novel single throttle control and additional pilot controls to support selection of engines during start, shutdown, and engine troubleshooting procedures. This design deviates significantly from current practice of providing throttles for each propulsion engine. Engine display recommendations are provided based on pilot feedback during a guided post-evaluation interview. Battery state of charge and battery health display recommendations were collected from all airline crews. The simplified engine displays design was rated excellent as measured with a usability scale. Quantitative metrics include airspeed tracking, time to complete checklists, time to make diversion decisions and the quality of the diversion decision. Recommendations for future studies are documented with supporting research and current observations about upcoming flight deck certifications.

autothrottle↗

Contingency Management with Human Autonomy Teaming

Automation is playing an increasingly important role in many operations. It is often cheaper faster and more precise than human operators. However, automation is not perfect. There are many situations in which a human operator must step in. We refer to these instances as contingencies and the act of stepping in contingency management. Here we propose coupling Human Autonomy Teaming (HAT) with contingency management. We describe two aspects to HAT, bi-directional communication, and working agreements (or plays). Bi-directional communication like Crew Resource Management in traditional aviation, allows all parties to contribute to a decision. Working agreements specify roles and responsibilities. Importantly working agreements allow for the possibility of roles and responsibilities changing depending on environmental factors (e.g., situations the automation was not designed for, workload, risk, or trust). This allows for the automation to "automatically" become more autonomous as it becomes more trusted and/or it is updated to deal with a more complete set of possible situations. We present a concrete example using a prototype contingency management station one might find in a future airline operations center. Automation proposes reroutes for aircraft that encounter bad weather or are forced to divert for environmental or systems reasons. If specific conditions are met, these recommendations may be autonomously datalinked to the affected aircraft.

dispatch↗

Pre-Departure Clearance (PDC): An Analysis of Aviation Safety Reporting System Reports Concerning PDC Related Errors

Airlines operating in the United States are required to operate under instrument flight rules (EFR). Typically, a clearance is issued via voice transmission from clearance delivery at the departing airport. In 1990, the Federal Aviation Administration (FAA) began deployment of the Pre-Departure Clearance (PDC) system at 30 U.S. airports. The PDC system utilizes aeronautical datalink and Aircraft Communication and Reporting System (ACARS) to transmit departure clearances directly to the pilot. An objective of the PDC system is to provide an immediate reduction in voice congestion over the clearance delivery frequency. Participating airports report that this objective has been met. However, preliminary analysis of 42 Aviation Safety Reporting System (ASRS) reports has revealed problems in PDC procedures and formatting which have caused errors in the proper execution of the clearance. It must be acknowledged that this technology, along with other advancements on the flightdeck, is adding more responsibility to the crew and increasing the opportunity for error. The present study uses these findings as a basis for further coding and analysis of an additional 82 reports obtained from an ASRS database search. These reports indicate that clearances are often amended or exceptions are added in order to accommodate local ATC facilities. However, the onboard ACARS is limited in its ability to emphasize or highlight these changes which has resulted in altitude and heading deviations along with increases in ATC workload. Furthermore, few participating airports require any type of PDC receipt confirmation. In fact, 35% of all ASRS reports dealing with PDC's include failure to acquire the PDC at all. Consequently, this study examines pilots' suggestions contained in ASRS reports in order to develop recommendations to airlines and ATC facilities to help reduce the amount of incidents that occur.

Montalyo, Michael L.↗

A Fuzzy Approach of the Competition on the Air Transport Market

The aim of this communication is to study with a new scope the conditions of the equilibrium in an air transport market where two competitive airlines are operating. Each airline is supposed to adopt a strategy maximizing its profit while its estimation of the demand has a fuzzy nature. This leads each company to optimize a program of its proposed services (frequency of the flights and ticket prices) characterized by some fuzzy parameters. The case of monopoly is being taken as a benchmark. Classical convex optimization can be used to solve this decision problem. This approach provides the airline with a new decision tool where uncertainty can be taken into account explicitly. The confrontation of the strategies of the companies, in the ease of duopoly, leads to the definition of a fuzzy equilibrium. This concept of fuzzy equilibrium is more general and can be applied to several other domains. The formulation of the optimization problem and the methodological consideration adopted for its resolution are presented in their general theoretical aspect. In the case of air transportation, where the conditions of management of operations are critical, this approach should offer to the manager elements needed to the consolidation of its decisions depending on the circumstances (ordinary, exceptional events,..) and to be prepared to face all possibilities. Keywords: air transportation, competition equilibrium, convex optimization , fuzzy modeling,

Charfeddine, Souhir↗

Air transportation

Control problems in airline operations particularly air cargo handling

Lambert, R. F.↗

Kennedy launch processing system

Airline operations approach to Cape Kennedy launch processing system for reduced hardware and operational costs of shuttle support

Parsons, W. E.↗

Fatigue design procedure for the American SST prototype

For supersonic airline operations, significantly higher environmental temperature is the primary new factor affecting structural service life. Methods for incorporating the influence of temperature in detailed fatigue analyses are shown along with current test indications. Thermal effects investigated include real-time compared with short-time testing, long-time temperature exposure, and stress-temperature cycle phasing. A method is presented which allows designers and stress analyzers to check fatigue resistance of structural design details. A communicative rating system is presented which defines the relative fatigue quality of the detail so that the analyst can define cyclic-load capability of the design detail by entering constant-life charts for varying detail quality. If necessary then, this system allows the designer to determine ways to improve the fatigue quality for better life or to determine the operating stresses which will provide the required service life.

Doty, R. J.↗

Flight evaluations of the effect of advanced control systems and displays on the handling qualities of a general aviation airplane.

Flight tests have shown that, by means of improved displays and advanced control systems, it is possible to transform a typical light airplane into a flying machine that borders on being perfect from a handling-qualities standpoint. A flight-director display and an attitude-command control system used in combination transformed a vehicle with poor handling qualities during ILS approaches in turbulent air into a vehicle with extremely good handling qualities. The attitude-command control system also improved the ride qualities of the airplane. A rate-command control system was less beneficial than an attitude-command control system. Although this paper deals primarily with general aviation aircraft, the results presented pertain to other types of aircraft. Short-takeoff-and-landing (STOL) aircraft would be a natural application of the control systems because, as a result of their low speeds, they encounter many of the handling-qualities problems noted on light aircraft. The improved ride qualities should be of interest to all airline operations, and for STOL aircraft in particular, because of their prolonged exposure to low-altitude turbulence.

Loschke, P. C.↗

Flight service evaluation of PRD-49/epoxy composite panels in wide bodied commercial transport aircraft

L-1011 aircraft fairing panel configurations were selected as test parts to compare the fabrication, costs and service performance characteristics of PRD-49 and fiberglass. These parts are currently fiberglass reinforced structure and the purpose of this program is to evaluate the results of direct substitution of PRD-49 fabric for the fiberglass. Three ship sets of these panels have been fabricated for a five year flight service evaluation on three L-1011 commercial airlines operating in widely diverse route structures. The standard tools and machining techniques used for fiberglass parts are unacceptable for cutting, trimming, and drilling the tougher PRD-49 fibers. Therefore, a machining development study was undertaken to provide the necessary new tools and machining techniques. After incorporating these new developments in the fabrication and installation of the panels, a manufacturing cost study revealed that the labor hours were only increased by about 12.5 percent.

Wooley, J. H.↗

One Airline's View of Mergers

Specific cases of airline mergers are discussed to show the legal aspects involved and the procedures followed. The effects of the mergers on the airlines involved are analyzed. The impact of the mergers on management, personnel, and the overall airline operations is reported.

Colodny, E. I.↗

The next forty years in aviation

A prediction of the status of various types of aviation activities which may be expected in twenty years is presented. The basic assumptions are that the population of the nation will continue to grow at more than 7 percent and that the need for air transportation of passengers and cargo will increase accordingly. Various predictions are also made for the developments in vertical takeoff aircraft, short haul airline operations, general aviation, and military aircraft. Areas of improvement are indicated for air navigation, air traffic control, night vision, quiet aircraft, and the use of hydrogen as a fuel.

Hawkins, W. M.↗

Ride quality of terminal-area flight maneuvers

Complex terminal-area flight maneuvers being considered for airline operations may not be acceptable to passengers. To provide technology in this area, a series of flight experiments was conducted by NASA using the U. S. Air Force Total In-Flight Simulator (TIFS) aircraft to obtain subjective responses of a significant number of passenger test subjects to closely controlled and repeatable flight maneuvers. Regression analysis of the data produced a mathematical model which closely predicts mean passenger ride-comfort rating as a function of the rms six-degree-of-freedom aircraft motions during the maneuver. This ride-comfort model was exercised to examine various synthesized flight maneuvers.

Schoonover, W. E., Jr.↗

An early glimpse at long-term subsonic commercial turbofan technology requirements

This paper reports on the exploratory investigation and initial findings of the study of future turbofan concepts to conserve fuel. To date, these studies have indicated a potential reduction in cruise thrust specific fuel consumption in 1990 turbofans of approximately 15% relative to present day new engines through advances in internal aerodynamics, structure-mechanics, and materials. Advanced materials also offer the potential for fuel savings through engine weight reduction. Further studies are required to balance fuel consumption reduction with sound airlines operational economics.

Gray, D. E.↗

Construction and verification of a model of passenger response to STOL aircraft characteristics

A technique for evaluating passenger acceptance of a transportation system's environment has been developed. This includes a model of passenger reaction to the vehicle, as well as the relative satisfaction compared to other system attributes. The technique is applied to two commercial airline operations - a U.S. commuter, and the Canadian Airtransit STOL system. It is demonstrated that system convenience and aircraft interior seating can play a large role in satisfying the passenger.

Jacobson, I. D.↗

AEMS implementation cost study for Boeing 727

Costs for airline operational implementation of a NASA-developed approach energy management system (AEMS) concept, as applied to the 727 airplane, were determined. Estimated costs are provided for airplane retrofit and for installation of the required DME ground stations. Operational costs and fuel cost savings are presented in a cost-of-ownership study. The potential return on the equipment investment is evaluated using a net present value method. Scheduled 727 traffic and existing VASI, ILS, and collocated DME ground station facilities are summarized for domestic airports used by 727 operators.

Allison, R. L.↗

Some early perspectives on ground requirements of liquid hydrogen air transports

The introduction of liquid hydrogen as a fuel for large, long haul air transports requires an integrated approach involving the air terminal authorities and the liquid hydrogen suppliers, as well as the airline operators and the air transport manufacturers. To illustrate the scope of the requirements necessary to support large air transports at the air terminals, perspectives are drawn to surface some concerns each of the principals may have to face, and to identify those that will require cooperative efforts to obtain integrated solutions.

Korycinski, P. F.↗