An Economic Method for Evaluating Electronic Component Obsolescence Solutions

Decisions Involving Multiple Obsolescence Events
The above relationships show optimal timing for redesign considering obsolescence of a single component. In reality, the engineering team is faced with defining solutions involving multiple components anticipated to become obsolete over the life of the product. Exact solutions require use of fairly complex modelling, using detailed data on all of the components within the LRU.
To provide the engineering team with additional guidance for multiple component obsolescence events, Boeing Electronic Products has expanded the above relationships to show the effect of annually recurring component obsolescence. We set the “annual cost” of parts projected to become obsolete (based on production usage) as constant, assessed the minimum cost solution
for these annually recurring obsolescence events, and superimposed on our “Break-even Year” chart a plot of the locus of the year for the minimum cost solution using the same ratio of NRE divided by “Annual parts usage cost”. The following figure shows the results: the cost-effective time point for redesign is moved forward, typically 2 to 3 years. From this data, approximations
for redesign timing can be made.