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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 sleeve cold-working process for fastener holes is a process that uses a tapered mandrel in conjunction with a disposable, prelubricated split sleeve to compressively prestress a significant zone around a fastener hole. This compressive prestressing offsets the stress concentration of the hole itself to produce substantial improvements in structural fatigue performance of fastened joints. The sleeve method allows higher degrees of prestressing than are possible with other methods and does not require precision controls and skills germane to other fatigue-rated hole preparation/fastener systems.

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.