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The auxiliary power unit (APU) requirements for commercial air transports have evolved from those of a convenience item to those of a highly integrated, heavily utilized, automated and sometimes essential, airplane system. This evolution has been driven by increasing demands for reliable airframe electrical and pneumatic power, fuel and weight efficiency, reduced crew workload, maintainability, and environmental accordance. Moreover, with the growth of extended range twin operations (ETOPS), the APU has become an essential back-up to primary airframe systems. This paper reviews the APU design criteria of past and present Boeing commercial jet transports and suggests the direction of future installations.

The aerospace industry uses flexible complex contoured structure in aircraft. To take advantage of advancements in engineering design, assembly methods, and inspection tools, the dimensional requirements for this kind of structure can be specified using Geometric Dimensioning and Tolerancing (GD&T) per ASME Y14.5M-1994, “Dimensioning and Tolerancing.” The 1994 revision of this standard includes some new features which can be used to specify the dimensional requirements for flexible complex contoured structure, but there are no examples on how GD&T can or should be applied. This paper gives some examples how GD&T can be applied on flexible complex contoured structure and how this usage specifies the dimensional requirements for such parts.

In today's competitive aircraft industry environment, new design, manufacturing, and assembly methods must be developed to lower costs and provide a more consistent product. One of the methods being implemented is Dimensional Management. Dimensional Management allows the evaluation of an entire manufacturing process and distribution of tolerances within that manufacturing process. Boeing has been working with Northrop-Grumman and several other suppliers to create a digital definition of the existing 747 fuselage design. This is part of an effort to implement a new manufacturing method known as Determinant Assembly. Dimensional Management plays a key role in implementing Determinant Assembly as well as incorporating into the engineering definition acceptance criteria that is better defined.

This paper briefly discusses the early background leading up to establishing the FAA Suspected Unapproved Parts (SUPs) Program Office and the Industry SUPs Steering Team. The various categories of parts comprising SUPs is reviewed. The main body of the paper reviews the various FAA and industry initiatives which target elimination of suspected unapproved parts.

The Department of Defense has made progress in modernizing its procurement of weapon systems. Modernization has identified a need to address Federal and military standards and specifications for parts, materials, and processes that represent many de facto national standards. The aerospace industry is proposing a transition to commercial specifications that meet the needs of Acquisition Reform. This paper reviews the history and benefits of modernization and describes the transition process.

This paper addresses the use of Hardware Variability Control (HVC) data to make process improvements in the assembly of the Next Generation 737 wing spars. The wing spars are the main structural component of the wing, and the two spars also make up two sides of each wing fuel tank. The wing spars are assembled using the Automated Spar Assembly Tool 3 (ASAT3). This paper covers the development of the ASAT3 HVC measurement plan, discusses the data collection methodology used, addresses process improvements made to the spar using the HVC data, and discusses next steps to improve the HVC plan.

Most commercial aircraft interior panels are constructed of honeycomb cored composite sandwich panels. The panels are conventionally joined using metal brackets fastened with screws. Over the past decade, most major interior fabricators have been in transition to a method of joinery using bonded interlocking joints. This method has recently been adopted by Boeing, and is known here as Tab and Slot Joinery. These interlocking joints are defined and illustrated. The history of the development effort is outlined. Design considerations are developed. Test programs are described, including a designed experiment and a special case fatigue test. Advantages of this new joinery method over the conventional are shown.

A novel method for improving the accuracy and lowering the cost of large NC drilling machines has been developed. The method employs a 3D tracking interferometer measurement system to measure and correct the position of the machine end-effector prior to each drill operation. This method eliminates many geometric and thermal errors inherent to NC drilling machines. The paper discusses the background, theory, initial implementation, test results and future enhancements of the method.

Adaptive control enables more productive use of high speed numerically controlled milling machines. With adaptive control, machines are programmed for optimum material removal, with the controller automatically reducing the material feed rate when heavy load conditions are encountered. The authors outline advantages of adaptive control and describe their testing technique for determining appropriate values for making maximally effective use of adaptive control.

Capacitance sensing probes have been in use for a number of years in the airframe assembly industry for characterizing diameters in straight and tapered fastener holes. A new type of capacitance probe was recently developed that simultaneously characterizes the countersink and shank diameters in holes drilled for index head rivets. The probe design and a unique methodology for a systems approach to qualifying a multi-probe inspection facility are presented in this paper.

High quality rivet installation is of critical importance to the aerospace industry, and the existence of gaps between the rivet head and the countersink is undesirable. Detection of gaps traditionally involves sectioning through rivet joints. Two concerns exist for this method of evaluation: it provides data only from the sectioned plane, and it has potential to alter the gaps. X-ray computed tomography (CT) was used to validate the effectiveness of the tradition sectioning method. It was revealed that the sectioning process generally increased the size of gaps. CT images also revealed that the gaps are not necessarily uniform around the rivet.

Making TRANAIR an easier to use wing design tool is an important step toward reducing wing design cycle time. This paper shows the accuracy of TRANAIR in analysis mode for complex configurations with attached flow. This accuracy allows the design part to correctly predict improvements due to design changes. We show the current steps required for the MultiPoint (MP) design version of TRANAIR and the state of refinements toward increasing ease-of-use of this system. Finally, we discuss some of the proposed ways to further improve how the user interacts with the TRANAIR system for MP design.

A series of flight tests over the ocean of a four engine turboprop airplane in the cruise configuration have provided a data set for improved understanding of wake vortex physics and atmospheric interaction. An integrated database has been compiled for wake-characterization and validation of wake-vortex computational models. This paper describes the wake-vortex flight tests, the data processing, the database development and access, and results obtained from preliminary wake-characterization analysis using the data sets.

The commercial airplane designer is faced with the challenge of balancing many factors to achieve an optimal airplane design, namely, how to reduce jet fuel use while also maintaining or improving emissions, noise, cruise speed, operating cost, range, reliability, maintainability, payload, takeoff field length, initial cruise altitude, and landing speed. Often, fuel efficiency improvements run counter to other design constraints imposed on the aircraft manufacturer by market forces. However, emerging engine and airframe technologies will help to continue the historical trend towards reduced fuel use. Five concept airplane designs will be reviewed that use future technology to enable the design of more environmentally friendly airplanes.

The Accurate Fuselage Panel Assembly Cell (AFPAC) is a semi-automated process that was developed for accurately assembling fuselage panels on the Boeing 757 model line. This method of assembly (prior to automatic fastening) uses a new generation, accurate CNC machine tool in conjunction with reconfigurable part fixturing techniques and specialized end-of-arm tools (end effectors). These end effectors drill coordination holes in detail parts and the skin, and trim the periphery of the skin. Machine control data (MCD) for positioning the machine tool and other subsystems are developed directly from the engineering digital definition (CATIA datasets). Reconfigurable part holding and feeding mechanisms are used to allow for product changes and reduce the overall cost of the workcell. This paper describes the AFPAC assembly system and how it compares with the traditional concept of fuselage panel assembly.

A study was conducted in a B-737 full flight simulator at the Boeing Customer Training facility to evaluate pilot decision making and performance under various situations in which decisions on whether or not to reject a take off had to be made and executed. A total of eight (8) situations were defined in which Go/NoGo decisions had to be made near V1 speed. Subjects included 24 Boeing instructor pilots and 24 line pilots from five different airlines. The sequence in which pilots encountered the situations was carefully balanced across subjects to control for learning effects. The results of the study are reported as quantitative data on RTO decisions, stopping performance, and procedure accomplishment plus a summary of data derived from post-run debriefings of the airline pilots. Lessons learned, conclusions, and recommendations for RTO training are presented.

Structural safety is an evolutionary accomplishment, and attention to detail design features is key to its achievement. A multitude of design considerations is involved in ensuring the structural integrity of Boeing jet transports that have common design concepts validated by extensive analyses, tests, and three decades of service. The active service life of commercial airplanes has increased in recent years as a result of increasing costs for fleet replacements. As airplanes approach their design service objectives, the incidences of fatigue and corrosion may become widespread. Continuing airworthiness of the aging jet fleet requires diligent performance from the manufacturer, the airlines, and airworthiness authorities. This paper gives an overview of traditional Boeing maintenance-related activities, joint industry/airworthiness authority initiatives, and the anticipated benefits for future generations of commercial airplanes.

The 777 flight deck will introduce two new functions, the electronic checklist function (ECL) and the flight deck communication function (FDCF), on interactive displays. Two cursor control devices (CCD) provide each pilot control of these new functions. The appearance and operation of the displays were standardized by specifying a common user interface (CUI). Ease of training and operation dictated an integrated design approach wherein the design and operational requirements for FDCF and ECL were developed together with the CCD and CUI.

The High Speed Civil Transport (HSCT) will be exposed to elevated temperatures during Mach 2.4 supersonic flight. While not as extreme as those encountered in other high speed flight efforts (NASP, Shuttle), thermal effects will impact decisions in almost all areas of material selection and design. Accurate temperatures are required to evaluate materials, structural concepts, cooling requirements, etc. Analyses show the importance of structural configuration, use of fuel as a heat sink, and surface properties on structural temperatures. Capability to accurately determine convection and radiation boundary conditions is important for future HSCT design.