Original Date: 10/20/1997
Revision Date: 01/18/2007

Northrop Grumman uses Variation Simulation Analysis (VSA) as a tool for redesigning components and process improvement. VSA is a commercial software package produced by the Variation Systems Analysis Corporation. This tool was used extensively during the Engineering and Manufacturing Development program phase for the F/A- 18 E/F program. In addition, most of the aircraft was modeled using VSA.

Northrop Grumman used VSA to redesign the vertical tail tip. Redesign was necessary due to an excessively tight fit of the parts. The analysis involved the examination of the materials, the processes, and the design of the components. The modeling and analysis evaluated the seal gap requirements; bondline requirements; tooling concepts and applications; process issues; close-out rib deflections in the autoclave; tolerances; and the vertical tail tip’s geometry. The bonded tip assembly was subjected to 13 iterations to converge on the optimized design. The joint between the bonded tip assembly and the tip rib required seven iterations to converge on an optimal design. Northrop Grumman used the recommendations from this analysis to develop the new design of the vertical tail tip for the LRIP program phase.

By using VSA on the E/F program, Northrop Grumman has developed better fitting parts. Proactive use of VSA allows the company to avoid defects, improve cycle time, and lower its costs. This very effective tool helps engineers and manufacturing personnel understand the process capability and control processes. In addition, Northrop Grumman reduced the number of product definition liaison personnel required on its production line from 56 to seven.

For more information see the Point of Contact for this survey.