Search Results

The use of paint automation in commercial aircraft production is being studied to reduce process cycle times, provide a higher quality paint finish, lower emissions, and increase process consistency. The cost of new aircraft paint hangars and increasing production rates is driving a need for increased capacity in existing facilities by using new coatings and technology. Testing of robotic painting at Boeing has uncovered unique differences between aerospace and automotive applications. Paint cure times, number of paint colors, environment control, and part size considerations are some of the issues that make aerospace application of coatings more difficult than automotive applications. Understanding the unique factors involved in the robotic application of commercial aerospace coatings is important for future advancements in application technology, gains in aircraft paint hangar capacity, delivering quality coating finishes, and lowering environmental footprint.

Since the 1960's, lightning protection of aircraft has been an important design aspect, a concern for the flying public, aircraft manufacturers and the Federal Aviation Administration (FAA). With the implementation of major aircraft structures fabricated from carbon fiber reinforced plastic (CFRP) materials, lightning protection has become a more complicated issue to solve. One widely used material for lightning strike protection of CFRP structures within the aerospace industry is expanded metal foil (EMF). EMF is currently used in both military and commercial passenger aircraft. An issue that has historically been an area of concern with EMF is micro cracking of paint on the composite structure which can result in corrosion of the metal foil and subsequent loss of conductivity. This paper addresses the issues of stress and displacement in the composite structure layup which contribute to paint cracking caused by aircraft thermal cycling.

Work defining advanced life support (ALS) technologies and evaluating their applicability to various long-duration missions has continued. Time-dependent and time-invariant costs have been estimated for a variety of life support technology options, including International Space Station (ISS) environmental control and life support systems (ECLSS) technologies and improved options under development by the ALS Project. These advanced options include physicochemical (PC) and bioregenerative (BIO) technologies, and may in the future include in-situ-resource utilization (ISRU) in an attempt to reduce both logistics costs and dependence on supply from Earth. PC and bioregenerative technologies both provide possibilities for reducing mission equivalent system mass (ESM). PC technologies are most advantageous for missions of up to several years in length, while bioregenerative options are most appropriate for longer missions. ISRU can be synergistic with both PC and bioregenerative options.

The significant problem of engine power-loss and damage associated with ice crystal icing (ICI) was first formally recognized by the industry in a 2006 publication [1]. Engine events described by the study included: engine surge, stall, flameout, rollback, and compressor damage; which were triggered by the ingestion of ice crystals in high concentrations generated by deep, moist convection. Since 2003, when ICI engine events were first identified, Boeing has carefully analyzed event conditions documenting detailed pilot reports and compiling weather analyses into a database. The database provides valuable information to characterize environments associated with engine events. It provides boundary conditions, exposure times, and severity to researchers investigating the ICI phenomenon. Ultimately, this research will aid in the development of engine tests and ICI detection/avoidance devices or techniques.

The International Space Station (ISS) will be the largest structure ever built in space. Differences between ISS and previous NASA vehicles led to developing new labeling methods, conventions and material. The challenge was to provide clear and meaningful identification, location, operations and safety information for the crews who will assemble, maintain and live onboard ISS.

One of the most critical functions of ECLSS is to maintain the atmospheric oxygen concentration within habitable limits. On the ISS, this function is provided by the Major Constituent Analyzer (MCA). During ISS (International Space Station) crew increments 7 thru 9, the MCA was at risk of imminent failure as evident by sustained high ion-pump current levels. In the absence of continuous constituent measurement by the MCA, manual methods of estimating partial pressure of oxygen (ppO2) and concentration levels need to be developed and validated to: (1) ensure environmental control and life support, (2) prohibit ISS system and hardware damage, and (3) enable planned ISS activities that effect constituent balance.

Through the use of an “Integrated Product Team” approach and new inspection techniques incorporating the latest in imaging capabilities and automation, the costs of some man-power intensive tasks can now be drastically reduced. Also, through the use of advanced eddy current techniques, the detectable size of cracks under flush-head fasteners can be reduced while maintaining reliable inspection. This article describes the evaluation and results obtained using eddy current technology to determine the minimum fasteners, Secondly, it describes the integrated efforts of engineers at Boeing DPD and Northwest Airlines in the successful application of MAUS eddy current scanning of the DC-10 circumferential and axial crow splices. The eddy current scanning greatly reduced the man-hour effort required for the existing radiographic inspection

Large diameter, tightly toleranced fastener patterns are commonplace in aerospace structures. Satisfactory generation of these holes is often challenging and can be further complicated by difficult or obstructed access. Bespoke tooling and drill jigs are typically used in conjunction with power feed units leading to a manual, inflexible, and expensive manufacturing process. For 777X flap production, Boeing and Electroimpact collaborated to create a novel, automated solution to generate the fastener holes for the main carrier fitting attachment pattern. Existing robotic automation used for skin to substructure assembly was modified to utilize extended length (up to 635mm), bearing-supported drill bar sub-assemblies. These Long Assembly Drills (LADs) had to be easily attached and detached by one operator, interface with the existing spindle(s), supply cutting lubricant, extract swarf on demand, and include a means for automatically locating datum features.

The Boeing 787 Dreamliner will be the most fuel-efficient airliner in the world when it enters service in 2008. To help achieve this, Boeing will utilize state-of-the-art carbon fiber for primary structures. Advanced manufacturing techniques and processes will be used in the assembly of large composite structures. Electroimpact has proposed a system utilizing the low recoil Low Voltage Electromagnetic Riveter (LVER) to drill and install bolts. A test program was initiated between Boeing Materials Process and Engineering (MP&E) and Electroimpact to validate the LVER process for swaging titanium collars on titanium pins in composite material. This paper details the results of these tests.

In the wake of the 9/11/2001 hijacking events, the Federal Aviation Administration (FAA) has emphasized the need for enhanced flight deck doors on commercial airplanes. The paper describes enhanced flight deck door, which meets the new FAA requirements for intrusion resistance and ballistic protection. In addition, the new door meets the existing requirements for rapid decompression, flight crew security and rescue.

Equivalent system mass (ESM) was defined in 1997 as an integral part of the Advanced Life Support project metric. It is particularly suited to comparing technologies that differ in mass, volume, power, cooling, and crew time during the early phases of a program. In principle, ESM can also be used to compare technologies that differ in other parameters. In practice, the necessary data is generally not available, and this limits this application. ESM has proven to be a useful tool. Like any tool, its strengths and weaknesses must be understood. This paper documents the history, capability and methods used in connection with ESM.

Advancements in electrical, mechanical, and structural design onboard modern more electric aircraft have added significant stress to the thermal management systems (TMS). A thermal management system level analysis tool has been created in MATLAB/Simulink to facilitate rapid system analysis and optimization to meet the growing demands of modern aircraft. It is anticipated that the tracking of thermal energy through numerical integration will lead to more accurate predictions of worst case TMS sizing conditions. In addition, the non-proprietary nature of the tool affords users the ability to modify component models and integrate advanced conceptual designs that can be evaluated over multiple missions to determine the impact at a system level.

The new combinations such as composites and titanium that are being used on today's new airplanes are proving to be very challenging when drilling holes during manufacturing and assembly operations. Gone are the days of hand drilling with high speed steel drills through soft aluminum structure, after which aluminum rivets would be swaged into those holes with very generous tolerances. The drilling processes today need to use cutter materials hard enough and tough enough to cut through hard metals such as titanium, yet be sharp enough to resistant abrasion and maintain size when drilling through composites. There is a constant search for better cutters and drills that can drill a greater number of holes. The cost of materials used in today's aircraft is much higher. The cutting tools are more expensive and the hole tolerances are much tighter.

The Boeing Company has developed a mobile robotic drilling and fastening system for use in assembly processes on the lower panel of a horizontally fixtured wing. The robotic system, referred to as Lower-panel Drilling and Fastening System (LPDFS), was initially developed as part of an initiative to minimize facilities costs by not requiring costly foundation work. It is designed to operate with a high level of autonomy, minimizing operator intervention, including that required for machine setup and tool changes. System design enables positioning the work piece at a lower ergonomic height for concurrent manual processes. In all aspects of design, the system will maintain maximum flexibility for accommodating future manufacturing changes and increases in production rate, while meeting the strict accuracy requirements characteristic of aircraft manufacturing.

Different options have been examined for providing minerals to plants for bioregeneration. The baseline option is to ship the minerals. The equivalent system mass of two different bioreactor systems for recycling a portion of these minerals, a fixed-film bioreactor and a stirred-tank reactor are calculated. Either option could reduce the ESM for providing these minerals for a 15-year mission to Mars, with 50% food closure.

Increased nickel concentrations in the IATCS coolant prompted a study of the corrosion rates of nickel-brazed heat exchangers in the system. The testing has shown that corrosion is occurring in a silicon-rich intermetallic phase in the braze filler of coldplates and heat exchangers as the result of a decrease in the coolant pH brought about by cabin carbon dioxide permeation through polymeric flexhoses. Similar corrosion is occurring in the EMU de-ionized water loop. Certain heat exchangers and coldplates have more silicon-rich phase because of their manufacturing method, and those units produce more nickel corrosion product. Silver biocide additions did not induce pitting corrosion at silver precipitate sites.

A summary of waste processes and waste process data is presented in the context of mission equivalent system mass. Storage, size reduction, drying, aerobic and anaerobic biodegradation, chemical oxidation, pyrolysis, and post processing are evaluated in the context of probable long-duration missions beyond LEO, and the probable quantities and types of wastes and of the other on-board systems. An assessment of the waste systems described in the ALS Reference Missions Document is presented, and rationale for some changes to these systems is provided.

Clothing accounts for a surprisingly large quantity of resupply and waste on the International Space Station (ISS), of the order of 14% of the equivalent system mass (ESM). Efforts are underway in the ISS program to reduce this, but much greater changes are likely to be possible and justifiable for long duration missions beyond low Earth orbit (LEO). Two approaches are being assessed for long duration missions: to reduce the mass of the wardrobe through use of lighter fabrics, and to clean clothing on board for reuse. Through good design including use of modern fabrics, a lighter weight wardrobe is expected to be feasible. Collateral benefits should include greater user comfort and reduced lint generation. A wide variety of approaches to cleaning is possible. The initial evaluation was made based on a terrestrial water-based washer and dryer system, as this represents the greatest experience base.

This paper discusses some of the analytical decisions that an investigator must make during the course of a life support system trade study. Equivalent System Mass (ESM) is often applied to evaluate trade study options in the Advanced Life Support (ALS) Program. ESM can be used to identify which of several options that meet all requirements are most likely to have lowest cost. It can also be used to identify which of the many interacting parts of a life support system have the greatest impact and sensitivity to assumptions. This paper summarizes recommendations made in the newly developed ALS ESM Guidelines Document and expands on some of the issues relating to trade studies that involve ESM.

Over 1,200 large diameter holes must be drilled into the side-of-body join on a Boeing commercial aircraft's fuselage. The material stack-ups are multiple layers of primarily titanium and CFRP. Due to assembly constraints, the holes must be drilled for one-up-assembly (no disassembly for deburr). In order to improve productivity, reduce manual drilling processes and improve first-time hole quality, Boeing set out to automate the drilling process in their Side-of-Body join cell. Implementing an automated solution into existing assembly lines was complicated by the location of the target area, which is over 15 feet (4 meters) above the factory floor. The Side-of-Body Drilling machines (Figure 1) are capable of locating, drilling, measuring and fastening holes with less than 14 seconds devoted to non-drilling operations. Drilling capabilities provided for holes up to ¾″ in diameter through stacks over 4.5″ thick in a titanium/CFRP environment.