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This paper explores the need for human factors and error management within the context of the general and corporate aviation environments. It discusses strategies currently employed in other segments of the aviation industry and how they might be utilized in the corporate and general aviation arenas. It also relates research findings and program successes experienced within the airline industry and makes recommendations as to how a consortial effort by industry organizations might be utilized to employ these strategies in corporate and general aviation operations.

The introduction of FAR23.562 to the Federal Aviation Regulations has necessitated the design and testing of aircraft seats with energy absorbing characteristics to minimize pelvic loads experienced when the seat environment is subject to specified acceleration pulses. Aircraft seat designers have applied various techniques to facilitate this energy absorption. Generally these techniques come at the expense of ease of manufacture and durability. This paper describes the development and testing of seating structures fabricated in a simple and easily reproducible form from sheet aluminium. The design employs both compressive buckling and plastic tensile deformation of the aluminium panels in the seat pan as the means of energy absorption. As the post buckled deflections required to provide sufficient seat stroke are large, the design process does not lend itself to simple theoretical analysis.

A series of side facing seat impact sled tests were conducted using the SID, EuroSID-1 and BioSID side impact Anthropomorphic Test Dummies (ATDs) at the FAA Civil Aeromedical Institute (CAMI). The tests were performed on a side facing sofa fixture with a rigid bulkhead adjacent to the forward end of the seat. The purpose of the research project was to examine the methods utilized by the automobile industry to assess thoracic injuries due to side impact accidents, and to investigate the potential applicability of these methods for side facing seats and sofas in civil aircraft. Tests were conducted with single and double occupants. The test conditions complied with the 16g 44 f/s horizontal impact specified in 14 CFR 25.562. Various side impact injury criteria were evaluated in the tests, including the Thoracic Trauma Index (TTI), Viscous Criteria (VC), rib deflection and pelvis acceleration.

A 500 pound (2.2 kN) increase in takeoff thrust per engine was predicted to increase the SJ30-2’s single engine minimum control speed (VMCA) to 109 knots (201.9 km/hr). To meet runway performance goals, VMCA had to be pushed below 97 knots (179.6 km/hr). Six types of vertical tail and rudder modifications were investigated analytically. Two vertical tail modifications and three ventral rudder configurations were tested in the wind tunnel. The tunnel showed 30° of ventral rudder deflection would reduce VMCA over 16 knots. Flight tests showed the deflected ventral rudder reduced measured VMCA speeds from 7.2 knots (13.9 km/hr) to 11.6 knots (21.5 km/hr). Other flight test techniques showed ventral rudder effectiveness to exceed that measured in the tunnel. In light of these results, a ventral rudder bias system has been incorporated into the production SJ30-2 design to assist the pilot during single engine events.

For many years manufacturer’s had to devote considerable work to demonstrate that an aircraft met the specific requirements. The indicator of credibility lies primarily in the award of Type Certification, marked by a Certification of Airworthiness. Since flight test engineering accounts for a major portion of aircraft manufacturer’s controllable cost; the implementation of structured methods and advanced operational procedures will yield the most dramatic single cost savings. The FTIMS/2000™ seamlessly links a complex array of strategic flight test business processes into a logical flow and is used as a true management tool. It is one of the only systems of its kind and is recognized by major aerospace corporations worldwide.

This paper argues in favor of a human-centered (anthropocentric) approach to modern manufacturing. The bases for these arguments are: (a) worker deskilling and creativity issues, (b) economics, and (c) unresolved problems in automation, such as software reliance and costs. Detailed arguments are avoided owing to space limitations. Finally, some issues confronting human-centered manufacturing are raised.

Age-related declines in sensory-motor and musculoskeletal systems may interfere with the use of computer pointing devices by older adults. This experiment compared older and younger adults’ ability to select onscreen targets using a mouse and two trackball designs (finger-ball vs. thumb-ball). Analysis of throughput values indicated that the mouse was superior to either trackball design, which supported equivalent levels of performance. For older computer users, the thumb-ball was associated with higher levels of perceived exertion. The results suggest the mouse may be a better input device but the finger-ball may represent a viable alternative for elderly with a reduced range of motion of the wrist.

The results of dynamic seat testing at four different test facilities with different test devices are presented. An acceleration-type sled, two deceleration-type sleds, and a drop tower were used in this evaluation. Repeatability between test facilities is discussed. Comparisons of the results obtained from the four test facilities, including pulse shapes, acceleration levels, measured injury criteria, and structural loads, are made. The findings of this program address the question of whether or not different test facilities and test devices produce comparable test and certification results.

The Lean and Agile Manufacturing Simulation Model simulates the concepts of lean and agile manufacturing. A “live” working factory model is used to contrast the operating styles between a typical “mass production” plant and a “lean” production plant. Participants work as a team to plan, fabricate, manufacture, assemble, and ship two types of products using three common manufacturing processes - Traditional Mass Production (Push), Just-In-Time Manufacturing (Pull), and Cellular Manufacturing (Cell). Model functions include; warehousing, fabrication, WIP storage, assembly, inspection, accounting and shipping utilizing a miniature factory model, complete with tools, fixtures, materials and shop floor paperwork transactions. The model initially utilizes a traditional Material Requirements Planning (MRP) based scheduling approach to operate the factory.

The development of efficient and reliable methods for the design and analysis of fastened structural connections is among the most important problems in aerospace applications because fastened structural connections are common sites of failure initiation. Numerical simulation of fastened structural connections is difficult because there are complicated interactions between the fasteners and the structural components being joined and one of the most important attributes of a fastened connection, the clearance, is a stochastic variable. This paper presents a mathematical model for frictionless shear connections and its implementation within the framework of the p-version of the finite element method.

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.

The residual strength of an aluminum panel with a centric hole and one cracked ligament was investigated experimentally. Each of the 7075-T6 aluminum panels which were tested included a cracked ligament of varying length on one side of the centric hole and an uncracked ligament on the other side of the hole. The failure of such a panel subjected to uniform tensile loading normally occurs according to the lower of two modes: brittle fracture or a net section type of yielding. On the other hand, the question of whether one or both ligaments fail is not easily answered. Results show that one or two ligament failure depends upon test conditions such as crack length and loading method. For short crack lengths, the uncracked ligament will fail almost simultaneously with the failure of the cracked ligament.

Multiple site damage (MSD) on aging aircraft accumulates from fatigue loading over a period of time. For ductile materials such as 2024-T3 aluminum, MSD may lower the strength below that which is predicted by conventional fracture mechanics. An analytical model referred to as the linkup (or plastic zone touch) model has previously been used to describe this phenomenon. However, the linkup model has been shown to produce inaccurate results for many configurations. This paper describes several modifications of the linkup model developed from empirical analyses. These modified linkup models have been shown to produce accurate results over a wide range of configurations for both unstiffened and stiffened flat 2024-T3 panels with MSD at open holes. These modified models are easy to use and give quick and accurate results over a large range of parameters.

The American Society for Testing and Materials (ASTM) sponsored a Symposium entitled Future Fuels for General Aviation Intermittent Combustion Engines[1] held on 29 June 1988, in Baltimore, Maryland. This event prompted the formation of an ASTM D02 Subcommittee J Section 2 Future Fuels For General Aviation Task Group [2], that successfully capped a ten year effort with the recent publication of ASTM D 6227-98 Standard Specification for Grade 82 Unleaded Aviation Gasoline [3]. This paper reflects on the Grade 82 UL Aviation Gasoline Specification development program[4,5], beginning with fundamental questions related to the quality of available feed stocks. It includes results of studies and tests undertaken by the Cessna Aircraft Company to demonstrate the feasibility of using the fuel described by the Specification in aircraft designed for its use.

ACE-100 provides the accepted method for estimating the fatigue life of empennage structures. It is based on airplane normal accelerations at the center of gravity (CG Nz). While there is a strong correlation between CG Nz and wing loads, little correlation exists with empennage loads. A Cessna 172P was instrumented for this flight loads program. It was found that significant loads were induced in the horizontal and vertical tails during roll and dutch-roll maneuvers indicating that the fatigue load spectra derived using ACE-100 may significantly underestimate the fatigue cycles experienced by the empennage. In addition, a method for monitoring in-flight tail loads was developed that does not require the installation of strain gages on each airplane.

Hundreds of components on the frame of an airplane are lubricated with grease. Since the performance of such components is critical, a number of grease specifications have been written to cover airframe grease applications. The proliferation of different airframe grease specifications complicates the maintenance of mixed fleets of airplanes and increases the opportunities for misapplication of grease. In the past decade, efforts have been made to reduce the number of greases required for airframe lubrication by enhancing the multipurpose nature of the relevant grease specifications. This paper compares four specifications that are used to specify airframe greases and describes a multipurpose grease which meets two of the major airframe grease specifications.

Aircraft engines need preheating to be able to start without damage in cold weather. It is possible to do this efficiently by placing a small amount of heat in the proper places. An installed electric system is very convenient and easy to use. A good design will be light weight and energy efficient. Corrosion in engines that operate in cold weather can be reduced or eliminated by the right preheater design and the proper operation of the engine. Some designs of preheater systems aggravate other problems. A certain amount of caution is needed in selecting the system. The unit should be specifically matched to the aircraft and engine.

This paper describes research to analyze widespread fatigue damage in lap joints. The particular objective is to determine when large numbers of small cracks could degrade the joint strength to an unacceptable level. A deterministic model is described to compute fatigue crack growth and residual strength of riveted panels that contain multiple cracks. Fatigue crack growth tests conducted to evaluate the predictive model are summarized, and indicate good agreement between experimental and numerical results. Monte Carlo simulations are then performed to determine the influence of statistical variability on various analysis parameters.

Two specific concerns that could affect safety limits for aging aircraft are the effects of corrosion damage and widespread fatigue damage (WFD) on structural integrity. A common joint in fuselage structure is the riveted lap joint, which overlaps two fuselage skin panels. This design creates complex loading conditions that require various analysis methods for accomplishing a durability and damage tolerance (DaDT) analysis. Under an Air Force research project, Boeing evaluated the capabilities of several advanced analysis tools for assessing the effects of corrosion and WFD on the structural integrity of riveted lap joints.

An experimental study was conducted to investigate ice-adhesion on clean and coated aluminum surfaces. A test apparatus using the parallel plate linear shear technique was designed along with a data acquisition system for conducting the tests and recording the experimental data. A low pulling rate was applied to specially prepared test specimens for measuring the strength of ice adhesion for a range of test conditions. The effects of surface roughness, surface contamination, and water impurity on ice adhesion were investigated. In addition, tests were conducted to evaluate the effectiveness of a low ice-adhesion coating applied to aluminum test specimens. The results obtained showed that the bond between ice and metal was considerably lower for tap water than for distilled water. For the clean and coated aluminum surfaces the strength of ice adhesion varied with specimen roughness. However, no clear trend was established between ice adhesion strength and surface roughness.