Refine Your Search


Search Results

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

Aerodynamic Design Considerations of Variable Geometry Aircraft

Aircraft designs have been characterized by an increasing utilization of variable geometry features as aircraft capabilities expand into new flight regimes. The trend seems likely to continue as requirements for new aircraft become continually more demanding. The successful application of variable geometry depends on several things: the understanding of the aerodynamic principles involved, efficient structure, and whether an overall worthwhile improvementin performance, maneuverability, or flying qualities is gained; since it certainly will cost more, be less reliable, and more difficult to maintain. The application of some existing and proposed variable geometry schemes to aircraft is discussed. The aerodynamic factors affecting low and high speed performance, maneuverability, and stability and control characteristics indicate some of the desirable and troublesome aspects of these concepts.
Technical Paper

Airport, Airspace, and NAS System Capacity Studies

“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.
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

An Objective Look at Helicopter Automation from a Test Pilot's Point of View

This paper will discuss some considerations regarding man-machine interface during helicopter instrument flight. Several misconceptions have existed regarding FAA helicopter IFR certification. In response to some concerns pertaining to “excessive workload considerations,” designers have responded with several configurations. Some of these configurations have highlighted the need to educate the designer and the pilot population that the pilot must have the option to “actively participate” in the flight activity during helicopter IFR operations. “Active participation” includes the option of flying the vehicle through the normal flight controls. In addition, there has been some confusion regarding the terms “stability augmentation systems” and “autopilot.” Some individuals use the terms interchangeably. This paper will discuss the various lessons learned during FAA certification of helicopters for IFR flight from a certification test pilot's viewpoint.
Technical Paper

Canard Certification Loads — A Review of FAA Concerns

Since the first airplane was certified in 1927, the standard configuration has been with the main lifting surface or surfaces forward of the stabilizing surface. Although some of the advantages of the canard configuration were recognized quite early - by the Wright Brothers, for example - canard surfaces have been used to date only as additional control surfaces on some military airplanes, and on some amateur built airplanes. As a result, the Airworthiness Regulations of Reference 1 address only tail aft configurations. When FAA was first approached regarding certification of a canard configured small airplane, an FAA/Industry Empennage Loads Working Group was formed to develop technical proposals for the necessary rule changes and policy. The concerns addressed by this working group are discussed in the following sections.
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

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

Civil Certification of Avionics Modifications in Military Transport Category Aircraft

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.
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

Demonstration of an Electrically Actuated Brake with Torque Feedback

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.
Technical Paper

Design and Flight Test of One-Man Operability in the F/A-18

The F/A-18 has the capability to perform a greater variety of fighter/attack missions than any other single-place aircraft ever produced. This paper will not address any new discussion of the “one vs. two” crewmember situation, but only present the human factors engineering history that produced the current man-machine interface in the F/A-18. The extensive software capability of the airplane has made changes found desirable during flight test reasonably easy to incorporate into production aircraft. These changes encompass everything from aircraft handling qualities and display formats (heads-down and heads-up) to radar and weapons system operation. Previous aircraft have depended, in varying degrees, on the unique capabilities of the pilot to compensate for inherent crew station/weapon system deficiencies.
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.
Technical Paper

Development of the McDonnell Douglas MD-90

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.
Technical Paper

FAA Certification Criteria for Critical and Essential Digital Systems

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.
Technical Paper

FAA's Trend Analysis Data System

The Federal Aviation Administration is charged with the promotion of aviation safety. It is made up of three levels of administration within which are the functional organizations that manage the FAA programs and services. The Flight Standards service, which develops and enforces all regulations affecting aircraft and airmen, is the functional organization directly responsible for promoting aviation safety. This paper describes the Flight Standards aviation safety program.
Technical Paper

Failure of Aircraft Structural Joints Under Impulse Loading

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.
Technical Paper

Flammability of Automotive Plastics

This paper compares the flammability of plastic automotive components to that of commodity, engineering, and specialty plastics as well as those used in commercial aircraft cabins with regard to performance in microscale combustion calorimetry tests. Not surprisingly, automotive components used in engine and passenger compartments are as flammable and ignitable as the commodity and engineering plastics of which they are made and much more flammable than those used in the interiors of aircraft.
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

Heat-Powered Environmental Control Systems for Fighter Aircraft

Heat powered ECS concepts using a Rankine or Stirling power cycle to drive a vapor compression refrigeration cycle were evaluated for future fighter aircraft. Arrangements with separated power cycle and refrigeration cycle working fluids were considered, as were arrangements combining these cycles via a common working fluid. Promising heat sources and working fluids for these concepts were identified. Haste heat sources in the propulsion system and airframe were compared with regard to heat capacity, temperature level, and collection system design complexity. A screening process, which distinguished between the requirements imposed by the power cycle and refrigeration cycle, was developed to select promising working fluids. Concepts were evaluated using various system arrangements, heat sources, and working fluids to minimize the ECS-related TOGW penalty.