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The Boeing Company is striving to improve quality and reduce defects and injuries through the implementation of lightweight “Right Sized” automated drill and fasten equipment. This has lead to the factory adopting Boeing developed and supplier built flex track drill and countersink machines for drilling fuselage circumferential joins, wing panel to spar and wing splice stringers. The natural evolution of this technology is the addition of fastener installation to enable One Up Assembly. The critical component of One Up Assembly is keeping the joint squeezed tightly together to prevent burrs and debris at the interface. Traditionally this is done by two-sided machines providing concentric clamp up around the hole while it is being drilled. It was proposed that for stiff structure, the joint could be held together by beginning adjacent to a tack fastener, and assemble the joint sequentially using the adjacent hole clamp up from the previous hole to keep the joint clamped up.

Boeing has relied upon the 767 ASAT (ASAT1) since 1983 to fasten the chords, stiffeners and rib posts to the web of the four 767 wing spars. The machine was originally commissioned with a Terra five axis CNC control. The Terra company went out of business and the controls were replaced with a custom DOS application in 1990. These are now hard to support so Boeing solicited proposals. Electroimpact proposed to retrofit with a Fanuc 31I CNC, and in addition, to replace all associated sensors, cables and feedback systems. This work is now complete on two of the four machines. Both left front and right front are in production with the new CNC control.

A team from the USA rotorcraft industry, NASA, and academia was established to create a validated high-fidelity computational fluid dynamics (CFD) icing tool for rotorcraft. Previous work showed that an oscillating blade with a periodic variation in angle of attack causes changes in the accreted ice shape and this makes a significant change in the airfoil drag. Although there is extensive data for ice accumulation on a stationary airfoil section, high-quality icing-tunnel data on an oscillating airfoil is scarce for validating the rotorcraft icing problem. In response to this need, a two-dimensional (2D) oscillating airfoil icing test was recently performed in the Icing Research Tunnel at the NASA Glenn Research Center. Three leading-edge specimens for an existing 15-inch chord test apparatus were designed and instrumented to provide the necessary data for the CFD code validation.

The Turret Head Fastening System is an enhancement of current three position “C-frame” wing riveting machines. It was designed and built by Boeing as a fully instrumented research machine in 1991 for the 777 Airplane, and as a potential retrofit package for conventional drill, rivet, shave wing assembly machines. It was designed to automatically install rivets and bolts and perform the required hole preparation prior to fastener installation. In its current form, it will clamp a panel; and then as the fastener requires, drill, coldwork, ream, countersink the hole; inspect the hole; apply sealant when required; install threaded fasteners or rivets; torque the nut, swage the collar or upset the rivet as required; shave the rivet to ensure flushness; and finally unclamp the part - all within the current working envelope of a drill, rivet shave machine. Currently, switching from rivets to bolts requires a 5 minute tool change.

A new look at tactical combat V/STOL design and utility as affected by emerging technology and mission concepts is given in this paper. History has shown that a certain level of useful load fraction must be attained before an airplane system can be considered operationally successful. Technology trends reviewed in this paper suggest that the time is here or at least near for V/STOL tactical aircraft to achieve a truly viable useful load fraction. Propulsion, structure, and controls technologies will contribute to the success of the tactical V/STOL system. In addition, aerodynamic technology as related to interference effects in hover and transition, and as required for efficient supersonic cruise and combat, significantly impacts the design solution. A unique approach to system design risk assessment is described with results giving technology leverage as a function of design options.

The term “3 inch ice shapes” has assumed numerous definitions throughout the years. At times it has been used to generally characterize large glaze ice accretions on the major aerodynamic surfaces (wing, horizontal stabilizer, vertical stabilizer) for evaluating aerodynamic performance and handling qualities after a prolonged icing encounter. It has also been used as a more direct criterion while determining or enforcing sectional ice shape characteristics such as the maximum pinnacle height. It is the authors’ observation that over the years, the interpretation and application of this term has evolved and is now broadly misunderstood. Compounding the situation is, at present, a seemingly contradictory set of guidance among (and even within) the various international regulatory agencies resulting in an ambiguous set of expectations for design and certification specialists.

The formation of ice over lifting surfaces can affect aerodynamic performance. In the case of helicopters, this loss in lift and the increase in sectional drag forces will have a dramatic effect on vehicle performance. The ability to predict ice accumulation and the resulting degradation in rotor performance is essential to determine the limitations of rotorcraft in icing encounters. The consequences of underestimating performance degradation can be serious and so it is important to produce accurate predictions, particularly for severe icing conditions. The simulation of rotorcraft ice accretion is a challenging multidisciplinary problem that until recently has lagged in development over its counterparts in the fixed wing community. But now, several approaches for the robust coupling of a computational fluid dynamics code, a rotorcraft structural dynamics code and an ice accretion code have been demonstrated.

Flight in icing for transport category aircraft certification presents a particularly challenging set of considerations to establish adequate safety commensurate with the associated risk while balancing design complexity and efficiency. A review highlighting important aspects of the regulatory evolution and guiding principles for flight in icing certification is presented, including the current standards and recent rulemaking activity.

Determining local ice crystal icing concentration factors in the region of the forward fuselage is critical for setting the Total Water Content levels for air data probe qualification testing. Simulation, modeling, and testing techniques for this concentration-factor phenomenon are still in their infancy, and there is currently not a significant amount of this type of analysis in the literature. A representative, 3D analysis was conducted using transport airplane geometry and flight conditions that explored the sensitivities resulting from parametric changes to flight and ice crystal icing conditions, particle modeling parameters, and bouncing effects.

The Particular Risks Assessment Document (PRA) is the compendium of the assessments accomplished during the development of a new airplane that relate to threats to the airplane from the outside environment (e.g. birdstrike, lightning, hail) and threats to the systems from events originating in other systems (e.g. rotorburst, flailing shafts, tire and wheel burst). These assessments are accomplished to ensure the robustness of the design to survive these threats. An extensive list of threats is developed and teams are formed to evaluate each of them. The results of these studies are collated into a document that provides a single point reference for the new airplane with regard to its ability to survive all known external threats. If PRAs have been accomplished on previous programs they can be used as a starting point for the new assessment, then the systems are reevaluated against the new design and differences created by new design features need to be added to the list.