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Aircraft manufacturers spend millions of dollars reworking blown fastener holes, especially in portable tool drilling situations. Oval, tapered, rifled, and oversize holes are costly rework issues currently commonplace in the industry. The most common causes of imperfectly drilled holes include spindle runout, insufficient clamp and feed force, out-of-balance drill feed forces, spindle windup, and lack of adequate feed control. This paper will focus on a next-generation drilling machine that utilizes a unique combination of hydraulics and pneumatics to solve the problems associated with legacy drilling units. Several design elements will be examined, such as the use of an on-board, 1000 PSI hydraulic pump, controlling both drill feed and clamp force. This greatly reduces the size and weight of the clamp and feed cylinders compared to legacy air systems, while increasing their force and rigidity.

The 757 and 767 airplanes provide maximum commonality in equipment, flight deck configuration and handling characteristics. Pilots with three-crew ratings will be qualified to fly either airplane with a three-crew requirement, and those with two-crew ratings will have the same flexibility. In addition to crew qualification, over 80% of the LRUs in the Flight Management System are interchangeable between similar crew configurations of the 757 and 767, i.e., they have the identical part number. Seventy-five percent of the LRUs are common to both the two-and three-crew configurations. Components that have engine-related software (the Thrust Management and Flight Management Computers) will be interchangeable between 757 and 767 aircraft powered by engines from the same manufacturer.

A two-engine, three-fan V/STOL airplane was designed to fulfill naval operational missions. Use of interconnected variable pitch fans led to a good balance between the requirements for high thrust and responsive control at low speed, and efficient thrust at cruise speeds. Engine-out requirements, integration of propulsion and aerodynamic controls, and the propulsion installation were the major factors influencing the configuration. An airplane with a multimission capability from both vertical and short takeoff was conceived.

Procedures for measurement and evaluation of aircraft noise are contained in FAR Part 36 which was formulated in the late sixties. Over six years experience with this regulation has resulted in more than 5000 noise certification actions on the Boeing family of commercial jet transports. This experience has identified several potential areas for improvement of the regulation. Recommendations are presented for modifications to those portions dealing with noise demonstration procedures and test limitations. It is believed these modifications will make complying with the regulation less complex, while improving the technical validity of measured noise levels.

A review is given of air cargo economics over the past 15 years. Changing fleet mix, cargo handling techniques, and fuel cost are identified as significant determinats of economic patterns. In a forecast of the next 10 years, the impact of wide-bodied freighters is assessed, particularly with respect to their use in intermodal, air/highway movement of large, prepacked shipments. Estimates of different aircraft/load modes are given; container design, aircraft configuration, and loading equipment are crucial elements in cost projections.

In the past, commercial airplane manufacturers have used analytical techniques and nonstructured pilot opinion for workload assessment. Analytic techniques are of particular value to the aircraft manufacturer since they offer both the potential for identifying and correcting workload problems early in the design phase when the cost of change is relatively low and a tool that can provide data for certification. One disadvantage to the available analytic techniques is their lack of fidelity in assessing mental effort. With the current shift of flight deck design placing more mental demands on the flightcrew, workload assessment has taken on a new challenge. The addition of formalized subjective measures to traditional objective analyses can provide information that validates the analytic- and simulation-based estimates of physical workload and enhances estimates of mental workload.

Commercial airlines use a variety of hydraulic fluid mixtures, some of which had been reported to cause increased valve erosion. An extensive test program was conducted to determine why certain mixtures of aircraft phosphate ester hydraulic fluids cause erosiveness in valves while others have negligible effect. Use of nonerosive mixtures is important to the aircraft industry to reduce the high cost of maintenance caused by erosion. Accelerated tests were conducted to identify erosive and nonerosive mixtures of presently available fluids. Chemical tests were conducted with a matrix of test fluids to establish methods that will predict the effects measured in erosion tests. Erosiveness of fluid mixtures can now be predicted by means of two laboratory measured electrochemical properties; wall current and threshold corrosion current density.