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Second generation, or toughened, epoxy resin systems are under consideration for use on a large composite primary structural part such as a wing. A method of evaluating the properties of these materials, while at the same time considering design, structural and manufacturing requirements has been developed. Processability requirements for toughened epoxy resin systems have been established. Cost efficient manufacturing methods, such as pultrusion, have been investigated and found to be a feasible production method for composite structure. The use of pultrusion as a fabrication method for partially staged parts to be co-cured at a later date is being evaluated.

A successful short-haul transport must satisfy customer and marketplace requirements and be attractive economically. This paper examines the marketplace in the late 1970 time period to determine the payload-range and other performance requirements for a wide-bodied twin-jet transport. Environmental and operating cost targets are established, and the size of the market is estimated. An “optimal” design is then described which essentially represents the best possible airplane using the technology available in the time period best suited to the customer and marketplace requirements. Design data are presented that show the sensitivities of the design to some of the primary configuration variables. Certain design compromises are considered that have to do with airframe commonality with the manufacturer's other transports.

The maintenance diagnostics problem is becoming more difficult as weapon systems, operational environments, and tactical requirements become more complex. Existing fighter aircraft have achieved greater than 95% built-in test (BIT) capability, but are experiencing high false removal rates due to fault detection/fault isolation (FD/FI> ambiguities. This paper will shows how to reduce the program risk by implementing testability features as front end requirements. Integrated Diagnostics activities are part of the design process to build testability and supportability into the weapon systems. By influencing the hardware/software design early in the program, a large payoff in logistics costs will result in the operational and support phase.

The high equipment investment cost of today's large transport aircraft, the high daily utilization desired or required for profitable operations, and the potential revenue losses associated with service interruptions make it mandatory for the manufacturer to take an active part in the early reduction and correction of service problems. The high investment, not only by the aircraft operators but also by the manufacturer, demands the establishment of a mutual participation team effort for early problem resolution. This paper deals with an aircraft manufacturer's approach to meeting this challenge. It discusses the accumulation and evaluation of service data, the investigations initiated to properly understand the problem, and the management procedures established to assure a safe and speedy problem resolution with a minimum of service interruption. Specific examples are used to illustrate the types of decisions reached.

This paper presents an overview of design considerations, design development, and maintenance practices required to certify a commercial transport aircraft and ensure continuing airworthiness in operation. Subjects discussed include philosophy and criteria of airworthiness with examples of their application; evolutionary nature of the design development; scope of development testing; and the process involving manufacturer, operator, and regulatory agency to ensure continuing airworthiness throughout the aircraft operational life. Also discussed are the recent revisions in airworthiness regulations, which, along with advances in technology, have resulted in changing trends in the approach to substantiating continuing airworthiness, particularly for structures.