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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.

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.

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.