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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.

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.

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.

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.

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.

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.

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.

During design of the 777 Airplane, light gage, near net section 2090-T86 extrusions were considered to reduce aircraft weight. The need to evaluate effects of fastener installation on 2090-T86 was indicated by a previous study documenting problems due to low short transverse tensile strength. Tests by Boeing installing fasteners into holes using interference fits showed 2090-T86 was more susceptible to damage from fastening than previously reported. Damage consisted of cracks normal to the short transverse direction around the periphery of the fastener hole. This report documents the test program conducted at Boeing.

The Automated Spar Assembly Tool (ASAT II) at the Everett, Washington, 777 Boeing manufacturing facility could be the largest automated fastening cell in the commercial aircraft industry. Based on the success of the ASAT I, Boeing's 767 spar assembly tool, the 285-foot long ASAT II cell was needed to accurately position and fasten the major spar components (chords and web), then locate and fasten over 100 components (ribposts and stiffeners) to assemble the 777 forward and rear wing spars. From its inception in 1990 to the first drilled hole in January 1993 and through two years of spar production, the more advanced ASAT II has proven to be a greater success than even its 767 ASAT I predecessor. This massive automated fastening system consistently provides accurate hole preparation, inspection, and installation of three fastener types ranging from 3/16 inches to 7/16 inches in diameter.

A new gage block system for measuring fastener gage protrusion has been developed that is precise and cost effective. A chamfered gage bore and shank constraint inserts provide improved wear characteristics and a ten to one reduction in block requirements. Accuracy and repeatability performance makes the system an attractive candidate for Statistical Process Control for the tightest tolerance fasteners. A new “block custom” calibration process assures accuracy and allows wider tolerances on gage block dimensions. Through better control of gage protrusion in fastener manufacturing, airplane manufacturers can expect improvements in fastener installation quality and eventually in customer satisfaction.

Boeing is currently fundamentally rethinking and radically simplifying the processes related to airplane configuration definition and production. The presentation will describe reasons for embarking on this effort and a description of the fundamental production control processes Boeing will deploy. Process Engineering will be described using Boeing's program as an example.

Implementation of a high speed drill motor with solid carbide drill bits, along with careful attention to all details of the process, has resulted in an extraordinary increase in drill bit life, as well as improvements in cycle time and hole quality. During the implementation of a new wing panel riveting machine for use on the 737NG and 757 models a major goal was to significantly improve the drilling process. The phase out of Freon™ as a coolant/lubricant on existing machines forced changes to the drilling process, which resulted in a significant reduction in drill life, from an average of approximately 1,500 holes per drill to 305 holes. The new process on the new machine has increased the average drill life 11,375% to over 35,000 holes, decreased the drill cycle time by 80%, and improved hole quality.

With the increasing shift toward automation with respect to fastener installation, the need has evolved for clearer definition of the process capability of new fastener installation automation systems. In light of Engineering design requirements, and to address the process capability issue, Boeing has developed and implemented D6- 56617, a machine certification process for automated fastening of fuselage structure. This philosophy was a new approach in the following ways: 1. Previously, engineering oversight of automated fastening systems was limited to wing structure applications. 2. The process requires that process capabilities and performance of the automated machinery itself be established by test. 3. The process requires that detailed Process Control Documents be developed and followed. 4. The process links the statistical test data to the day to-day operating parameters of the machine.

At the 1990 Annual Aerospace/Airline Plating and Metal Finishing Forum, The Boeing Commercial Airplane Group presented information on boric acid/sulfuric acid anodizing (BSAA) as a replacement for chromic acid anodizing (CAA) to meet environmental regulations. This paper presents an update on the BSAA process and the status of production implementation. Background information will be reviewed including environmental issues and modifications of CAA to meet current EPA regulations. The results of BSAA process optimization, corrosion protection performance and compatibility with aircraft finishing will be given. Production implementation experience such as process control and facility requirements, including the status of BSAA for MIL-A-8625, Type IC (Anodizing, Non-chromic Acid, Meeting Type I Requirements) usage will be reviewed.