Metrication - A Program Approach

This paper presents the metric program approach taken by the Boeing Aerospace Co. in the design and fabrication of the PHM hydrofoil ship. The program approach was to maintain a strict metric base line allowing exceptions only where extensive qualifications, schedule impact, costs, and reductions of performance were imposed by a metric design. The program metric implementation plan is described. A discussion is provided of the metric problems encountered and the solutions evolved. The PHM ship evolves as a hybrid design where the structural design is metric and some of its operating systems are inch designs. An analogy is made relating the approach to more sophisticated aerospace-type programs as spacecraft, aircraft, etc. The analysis is made on the basis of a need for additional aerospace quality engineering metric standards in order to produce a complete metric design. The paper advocates an early start in creating key engineering metric standards and the need for industry/government cooperation to reduce cost.