2.5 Management Issues

The following ESS management issues and guidance need to be considered to increase the probability of implementing a viable ESS program:

• How critical are the items proposed for ESS and what level of quality is required? Criticality would be high if a failure of the item results in high probability of loss of life or an inability to complete a mission, high life cycle cost, or high cost of failure.
  

• The quantity to be procured should be considered. Where small quantities are involved and the item does not qualify as a high criticality item as given above, then it may be cost effective to use only the relatively low cost thermal cycling screens.
  

• The tailoring and optimization processes described in this document may result in stress levels or other ESS parameters that are less than those of the baseline provided in Tables 3-3 and 3-4 . In all cases, appropriate rationale and data should be presented to justify the ESS conditions to be applied.
  

• The type of random vibration should be considered. Should true random vibration excitation or a low cost alternative such as quasi-random (pneumatic) vibration excitation be used for the detection of flaws?
  

• The contractor's proposed ESS program plan should emphasize the following:
  
  - Commitment to and understanding of ESS
  
  - Failure reporting and corrective action system (FRACAS). A FRACAS should be in place and operating.
  
  - Span of control for ESS. If ESS is being performed by multiple subcontractors, what is their degree of implementation?
  
  - Planned ESS profile optimization technique. The Services recommend one of four random vibration techniques, and one of two thermal cycling techniques. Each has both advantages and disadvantages.
  
  - Managerial and technical approaches to ESS. The plan should include proposed methods for determining initial screening environment, applicable assembly levels, data collection, failure analysis and corrective action, and procedures or methods to be used in altering the program.
  
  - Nondevelopment items (NDI), such as commercial off-the-shelf and domestic or foreign military items, if those items have been determined to meet government requirements
  

• The Government program manager should also address the following additional issues:
  
  - ESS profile requirements should not be specified in the RFP. In general, it is better to allow contractors to propose an ESS profile than to specify a particular profile, unless the contract is a reprocurement and the original profile holding fixtures, vibration machine and chamber capabilities are contained or referenced on the drawings and are found to be satisfactory. (Note: the original profile may have to be modified due to changes in the production process and component manufacturing variability.)
  
  - The ESS and quality history of the contractor