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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.

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.

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.

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.