Methodology to Assess Assembly Variation in Aircraft Fuselage Structures

A methodology has been developed to understand the sources of detail part and assembly variation in airplane manufacture. This methodology includes the use of various computational software and statistical tools, as well as newly-developed mathematical models. This paper describes using this methodology to investigate assembly variation in general, and variation in detail-part geometry in particular. It discusses uncertainty in the method of selecting a datum from relative coordination holes and in determining the data offset from the measured datum to the airplane design coordinate system. The methodology was used to predict assembly variation. The study evaluated the validity and uncertainty of using multiple measurement devices and methods of collecting data. This methodology was developed to analyze variation in airplane fuselage structure. It is also applicable to production variation in the shipbuilding and automotive industries. The methodology described herein is part of an effort to reduce production costs effectively by intelligently reducing variation.