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Journal Article

Compliance with High-Intensity Radiated Fields Regulations - Emitter's Perspective

NASA's Deep Space Network (DSN) uses high-power transmitters on its large antennas to communicate with spacecraft of NASA and its partner agencies. The prime reflectors of the DSN antennas are parabolic, at 34m and 70m in diameter. The DSN transmitters radiate Continuous Wave (CW) signals at 20 kW - 500 kW at X-band and S-band frequencies. The combination of antenna reflector size and high frequency results in a very narrow beam with extensive oscillating near-field pattern. Another unique feature of the DSN antennas is that they (and the radiated beam) move mostly at very slow sidereal rate, essentially identical in magnitude and at the opposite direction of Earth rotation.
Technical Paper

A Taxonomic Analysis of Terminal Air Traffic Control/Pilot Communications

Voice communications are crucial to safe and efficient air traffic operations. Controllers are required to use standard phraseology, and pilots are encouraged to use it when talking to controllers. Incomplete or inaccurate communications were implicated in mishaps such as the Tenerife accident. This research examined the frequency of phraseology deviations in a sample of 5,000 transmissions from 3 terminal facilities. The Aviation Topics-Speech Acts Taxonomy (ATSAT) was used to develop baseline data and analyze controller/pilot communications. Clearance instructions were transmitted most frequently and they contained a higher percentage of deviations from standard phraseology than any other speech act category. Identification of the types of errors typically associated with specific miscommunications could result in implementing new training approaches that ensure a higher compliance with standard procedures and improve standard phraseology usage.
Technical Paper

An FAA Analysis of Aircraft Emergency Evacuation Demonstrations

Average continuous flow rates for each type of aircraft exit were examined in 89 full-scale evacuation demonstrations. Passengers tend to form continuous lines at available exits when evacuating an airplane. The study concludes that, with rare exception, the passenger rates of egress from the same type exit on different make and model airplanes are not significantly different. Passenger cabin configuration, seat pitch, and aisle width have no significant bearing on the egress rates provided the aircraft certification requirements for minimum aisle width and exit accessibility are met. Injuries resulting from actual emergency evacuations and evacuation demonstrations are also examined.
Technical Paper

Effectiveness of Seat Cushion Blocking Layer Materials against Cabin Fires

Materials are available for preventing or retarding aircraft cabin fires involving urethane foam seat cushions. Realistic fire tests performed in a wide-body test article demonstrate that some in-flight and ramp fires can be prevented, and that the allowable time for safe evacuation can be significantly extended during a survivable postcrash fuel fire, when the urethane foam seat cushion is covered by a “blocking layer” material.
Technical Paper

Certification Issues for a Tilt-Rotor Aircraft

Powered-lift aircraft, such as the V-22 tilt-rotor, are likely to spin-off a civil version. The present FAA airworthiness certification standards are not considered to be adequate for these unique aircraft. The FAA has drafted certification criteria and held a public conference to review the draft and identify significant technical certification issues that require further effort to establish correct standards for powered-lift aircraft. Some of those issues are discussed.
Technical Paper

Certification Issues Regarding Advanced Technology Control Systems in Civil Rotorcraft

Microprocessor technology is allowing functions in aircraft to be implemented to a greater degree by digital process control than by conventional mechanical or electromechanical means. A review of this technology indicates a need for updated certification criteria. A high level of commitment to the technology such as fly-by-wire is completely beyond the scope of existing certification criteria. This paper emphasizes the areas of software validation levels, increased concern with basic power system qualification, and increased environmental concerns for electromagnetic interference and lightning.
Technical Paper

Activities of the Federal Aviation Administration’s Aviation Weather Research Program

Weather is a major cause of aircraft accidents and incidents and the single largest contributor to air traffic system delays. Through improvements in the knowledge of current weather conditions and reliable forecasts, the Federal Aviation Administration (FAA) can improve aviation safety, increase system capacity, and enhance flight planning and fuel efficiency. The FAA has established an Aviation Weather Research (AWR) program to address specific requirements for weather support to aviation by providing the capability to generate more accurate and accessible weather observations, warnings, and forecasts and also by increasing the scientific understanding of atmospheric processes that spawn aviation weather hazards. The goal of AWR is to provide meteorological research that leads to the satisfaction of specific aviation weather requirements.
Technical Paper

The Discrete Address Beacon System in the Air Traffic Control Environment

Many problems exist in meeting the future surveillance and communication needs of air traffic control. Many functions and services are now being developed for eventual implementation beginning after 1977. The operation, role, and impact of the Discrete Address Beacon System in meeting these needs and functions are discussed in this paper.
Technical Paper

Vertical Drop Test of a Narrow-Body Transport Fuselage Section with Overhead Stowage Bins

A 10-foot-long fuselage section from a Boeing 737-100 airplane was dropped from a height of 14 feet generating a final impact velocity of 30 feet per second. The fuselage section was configured to simulate the load density at the maximum takeoff weight condition. The final weight of 8870 pounds included cabin seats, dummy occupants, overhead stowage bins with contents, and cargo compartment luggage. The fuselage section was instrumented with strain gages, accelerometers, and high-speed cameras. The fuselage sustained severe deformation of the cargo compartment. The luggage influenced the manner in which the fuselage crushed, affecting the gravitational (g) forces experienced by the test section. The seat tracks experienced 15 g's vertical deceleration. Although numerous fuselage structural members fractured during the test, a habitable environment was maintained for the occupants, and the impact was considered survivable.
Technical Paper

Transport Airplane Fuselage Section Longitudinal Impact Test

A transport airplane fuselage section with a full complement of cabin seats and anthropomorphic test dummies was longitudinally impact tested at a condition that approached the ultimate strength of the airframe protective shell structure. Airframe structural responses, seat/floor reaction loads, and the interactive effects of secondary impacts between multiple cabin seat rows were investigated. The scope and conduct of the test are presented together with some preliminary analyses of the test results.
Technical Paper

Radar Detection of High Concentrations of Ice Particles - Methodology and Preliminary Flight Test Results

High Ice Water Content (HIWC) has been identified as a primary causal factor in numerous engine events over the past two decades. Previous attempts to develop a remote detection process utilizing modern commercial radars have failed to produce reliable results. This paper discusses the reasons for previous failures and describes a new technique that has shown very encouraging accuracy and range performance without the need for any modifications to industry’s current radar design(s). The performance of this new process was evaluated during the joint NASA/FAA HIWC RADAR II Flight Campaign in August of 2018. Results from that evaluation are discussed, along with the potential for commercial application, and development of minimum operational performance standards for future radar products.
Technical Paper

Changing Airworthiness Requirements for Air Taxi Operators and Their Effect on Manufacturers of Small Airplanes

Important provisions are highlighted with respect to the additional airworthiness standards being considered by the Federal Avaiation Administration for small airplanes capable of carrying more than 10 occupants which are intended for use in air taxi and commercial operations. Information is presented on the background leading to these provisions and on their impact on manufacturers and operators. These new standards would result in a significant increase in the level of safety which is more commensurate with the class of operation, the increased occupant capacity, and the expanded volume of operations anticipated for these airplanes.
Technical Paper

Small Airplane Vertical Impact Test Program

The crash impact characteristics of commuter category airplanes has recently been established using empirical procedures based on full scale aircraft impact test data for a range of aircraft sizes[1]. To compliment that empirical approach the Federal Aviation Administration (FAA) initiated a full scale commuter category airplane vertical impact test program. Those airplane vertical impact tests were structured to evaluate the airframe's capability to maintain its structural integrity and provide a protective shell for its occupants, to quantify the acceleration impact response characteristics of the airframe, and to evaluate the means necessary to provide occupant pelvic/lumbar column load injury protection up to the limits of survivable impact conditions.
Technical Paper

Requirements, Performance and Integration of Modern Navigation Aids

The need to improve the efficiency and capacity of the Air Traffic Control and Navigation System has placed greater emphasis on the functional integration of subsystems which have been treated independently in the past. This paper presents results of limited test programs designed to explore the relationship of terminal area navigation and the air traffic control system, and to show the benefits of an optimum combination of both functions. The need for further analysis is indicated with respect to carrying out the third generation system design postulated by the DOT Air Traffic Control Advisory Committee. It is concluded that functional integration of ATC and navigation in the terminal area presents the greatest challenge. In other areas, such as enroute, the availability of new, integrated avionics systems provides an expanded operational capability.
Technical Paper

Reactions of Pilots to Warning Systems for Visual Collision Avoidance

The FAA conducted a series of six experiments having application to the development of pilot warning instruments (PWI). The experiments were concerned with the effect of warning rates on pilot performance, pilot response to imminent collision threats, the evaluation of scanning patterns, the value of warning-only, the effect of relative motion on pilot performance, and the effect of PWI display sector size. The results of these experiments offer a variety of useful data in the area of visual collision avoidance.
Technical Paper

Data Bases of Aviation Incidents Resulting from Human Error

This paper presents a description of several Federal Aviation Administration (FAA) incident data systems that contain information on events which result primarily from human error. These data systems include reports of near midair collisions, operational errors, pilot deviations, and events reported through the Aviation Safety Reporting System (ASRS). Over 17,000 incident reports are received and stored in these data bases annually. This paper discusses the information content of the data bases, reporting procedures, system limitations, proposed improvements, and uses of the data.
Journal Article

Framework for Unmanned Aircraft Systems Safety Risk Management

Although Unmanned Aircraft Systems (UAS) have now for some time been used in segregated airspace where separation from other air traffic can be assured, potential users have interests to deploy UAS in non segregated airspace. Recent technological and operational improvements give reason to believe that UAS safety and performance capabilities are maturing. But the skies can only really open up to UAS when there is an agreed upon UAS safety policy with commonly accepted UAS Safety Risk Management (SRM) processes enabling to show that the risks related to UAS operations in all the different airspace classes can be adequately controlled. The overall objective is to develop a UAS SRM framework, supporting regulators and applicants through provision of detailed guidelines for each SRM step to be conducted, including 1) system description, 2) hazard identification, 3) risk analysis, 4) risk assessment, 5) risk treatment.
Technical Paper

Determining a Safety Baseline for Unmanned Aircraft Systems

Unmanned Aircraft Systems (UAS) emerge as a viable, operational technology for potential civil and commercial applications in the National Airspace System (NAS). Although this new type of technology presents great potential, it also introduces a need for a thorough inquiry into its safety impact on the NAS. This study presents a systems-level approach to analyze the safety impact of introducing a new technology, such as UAS, into the NAS. Utilizing Safety Management Systems (SMS) principles and the existing regulatory structure, this paper outlines a methodology to determine a mandatory safety baseline for a specific area of interest regarding a new aviation technology, such as UAS Sense and Avoid. The proposed methodology is then employed to determine a baseline set of hazards and causal factors for the UAS Sense and Avoid problem domain and associated regulatory risk controls.