Search Results

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.

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.

The testing of a titanium matrix composite (TMC) F-15 nose gear outer cylinder is discussed. Two cylinders were fabricated. An entire F-15 nose gear was assembled using the first cylinder. This test gear underwent static structural tests to three critical loading conditions and functional evaluations including load-stroke, rebound snubbing, jig drops and strut stroke cycling. The TMC cylinder successfully completed both groups of testing with no signs of structural or functional degradation.

Recent changes in DoD procurement directives have encouraged the purchase of civilian products for use in certain military applications. One such application is the upgrade of avionics suites with the Global Positioning System (GPS) in military air transport aircraft to meet joint civil-military operational requirements. This paper reviews the Commercial Off-the-Shelf (COTS) concept and the proper use of TSOs, ACs, and FARs in both the design and integration process.

This paper describes the recently established Commercial Aviation Alternative Fuel Initiative (CAAFI), including its goals and objectives, as well as presents an alternate fuel roadmap that was originally generated by industry and refined by the CAAFI stakeholders. CAAFI is designed to coordinate the development and commercialization of “drop-in” alternate fuels (i.e. fuels that can directly supplement or replace crude oil derived jet fuels), as well as exploring the long-term potential of other fuel options. The ultimate goal is to ensure an affordable and stable supply of environmentally progressive aviation fuels that will enable continued growth of commercial aviation. This initiative is organized into four sub-groups: Research and Development (R&D), certification, environment, and economics & business. The R&D group seeks to identify promising new drop-in alternate fuels, and to foster coordination of development efforts.

Many of the certification regulations in 14 CFR Part 25 are by design, broad and as such, can be subject to large differences in the interpretation of what constitutes adequate compliance. Advisory Circulars (AC's) were developed for many of the regulations to assist industry, as well as certification personnel, with what is considered an acceptable, but not the only means, of compliance. However, there are many regulations where no advisory material is available. In these cases, the “acceptable means” of compliance can vary to a greater degree among the various aircraft certification offices. This difficulty is aggravated as new applicants and regulatory personnel enter the certification field. Recent discussions and interpretations on the usage of an avionic unit's mean time between failure or MTBF for its detectable faults as the basic repair rate for undetected or latent faults, is a subject area where no significant advisory material exists.

McDonnell Douglas has radically changed its approach to new product development under an internal project called Design, Manufacturing and Producibility Simulation (DMAPS). The new process has four steps: concept baseline, concept layout, assembly layout and build-to-package; each of which relies on three dimensional master solid models and a variety of advanced simulation and modeling tools. The result is a disciplined process that eliminates non-value added activity and provides all Integrated Product and Process Team (IP2T) members with the tools needed to effectively perform assigned tasks. McDonnell Douglas applied the new approach to a redesign of the T-45A Horizontal Stabilator. This project demonstrated that three dimensional master modeling can eliminate two dimensional drawings and enable physical mockups to be replaced by computergenerated virtual prototypes.

“As we handle more operations and passengers in the air, we must make certain we have the capacity to handle increased traffic on the ground.” - Jane Garvey, FAA Administrator (4/20/98) The FAA Technical Center (Aviation System Analysis and Modeling Branch, ACT-520) has been responsive to the FAA Airport Capacity Program customers for the past 22 years, developing, testing, and applying airfield and airspace simulation models. More than 90 capacity studies have been completed with ACT-520 personnel contributing their technical expertise to the Airport Design Teams. The teams are comprised of FAA personnel, airport operators, air carriers, other airport users and aviation industry representatives at major airports throughout the US. Initial studies focused on modeling airport operations from final approach, taxi, gate operations and departure processing. Later in the program, local airspace studies were included in some airport study efforts.

The Federal Aviation Administration (FAA) has recognized that there is a need to establish an orderly path to move Research, Engineering & Development (RE&D) aviation weather products into an operational environment. To address this need, FAA’s Air Traffic System Requirements Service (ARS) established the Aviation Weather Technology Transfer (AWTT) Board with the principal mission to manage and accelerate the transfer of RE&D products into operations. The board is comprised of members that cut across FAA services and includes representation from the National Weather Service (NWS). The board encourages the development of new aviation weather products that improve the depiction and forecasting of weather events that affect not only the safety of the National Airspace System (NAS) but also the efficiency. This paper describes how the board manages this technology transfer process and how it decides whether a product is acceptable for experimental evaluation or operations.

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.

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.

This paper describes a Robotic Cell, constructed and integrated in the McDonnell Aircraft Robotics Lab, for the purpose of demonstrating “freehand” (unstabilized) drilling and blind fastener installation. The cell operates without the use of hard tooling for end effector stabilization. The cell incorporates a jointed arm robot, a computer controlled drill and countersink end effector, an automatic fastener installation end effector, an automatic head shaving end effector, quick change equipment, and a programmable logic controller. The drill/countersink end effector provides high quality holes and countersinks utilizing a conventional industrial robot without the aid of hard tooling. It can be programmed with multiple feeds and speeds, automatically control chip load and cage force, and has the ability to detect broken bits. The fastener installation end effector employed is capable of installing self locking threaded blind fasteners (blind bolts) of multiple sizes and grip lengths.

As a part of its International Aging Aircraft Research Program, the Federal Aviation Administration is establishing a state-of-the-art Flight Loads Data Collection Program. Data collected in this program will provide the necessary mission profiles and load spectra information to characterize typical fleet service usage for the regional/commuter service life extension program. In addition, these data are applicable for both a safe life fatigue analysis and a damage tolerance fracture mechanics analysis. This paper describes the FAA approach and schedule for instrumenting fleet service aircraft, and the data reduction process.

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.

The issues involved in certifying head-up displays for civil aircraft are reviewed and proposed guidelines for the certification of head-up displays are presented. These guidelines are based on experience with civil and military head-up displays and follow the intent of the existing rules.

Douglas developed the MD-90, an IAE V2500-powered derivative of the MD-80, to satisfy a customer need for a more environmentally - friendly 150-seat, short/medium range jet transport. The program was launched in late 1989 with requirements to: significantly reduce community noise and engine emissions improve aircraft fuel efficiency make other technical improvements where cost effective for the customer. The aircraft was certificated in November 1994 and entered airline service in April 1995. The MD-90 meets all of its technical requirements.

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.

Numerical simulations indicate that blast loading on aircraft structural joints can impart loading rates in excess of 10 Mlb/sec (ten million pounds per second, Reference 1). Experimental evidence, on the other hand, suggests that mechanical joint failure loads are highly loading rate dependent; for example, the failure load for a dynamically loaded tension joint can double from its static value. This paper discusses the progress and to-date findings of research on the assessment of strength failure of aircraft structural joints subjected to loading rates expected from an internal explosive detonation, and several associated experimental procedures to generate such dynamic loading. This work is conducted at MDC and at the University of Dayton Research Institute (UDRI) in support of the FAA Aircraft Hardening Program.

The U.S. Air Force has recognized the need for an alternative to the conventional hydraulic brake system. Hazards associated with fires and the maintenance required for a hydraulically actuated system are the principal drawbacks of hydraulic brake systems. In addition, an alternative brake system will be required to support a “More Electric” aircraft of the future. The solution to these problems was provided by the “Electrically Actuated Brake Technology (ELABRAT)” program, a three year program sponsored by the Flight Dynamics Directorate at Wright Patterson AFB. ELABRAT developed and demonstrated an Electromechanically Actuated (EMA) brake system to replace the existing hydraulically actuated piston housing and associated hydraulic control hardware.

The advent of digital electronics for use in civil aircraft, particularly the new technology represented by central processor and microprocessor controlled systems, represents a major challenge to the aviation industry. The Federal Aviation Administration (FAA) is charged with the responsibility of evaluating these systems to determine if they can be used safely. The complexity of these systems as compared to their analog counterparts in use today makes their evaluation difficult. This paper outlines the major concerns of the FAA with the use of software controlled digital systems for airborne applications. The methods which can be used by members of the aviation industry to obtain FAA certification of these systems are also discussed. The proposal of Special Committee SC-145 of the Radio Technical Commission for Aeronautics (RTCA) form the basis of the design methodology which is described for the successful development of the computer programs (software) to be used by these systems.