Cost Considerations Based on Reliability of a Mission Critical System
Bondi, S¹; Ekker, D.²; Unal, R.^1
1Old Dominion University; ²Tidewater Community College

A major issue in system design is the estimation of a cost factor of reliability for mission critical equipment. This paper presents a case study about a mission critical system under consideration for replacement due to reduced mean time between failure (MTBF) and a significant increase in cost of the current system. The system is made up of two redundant sub-systems which are constantly monitored to ensure proper operation. The loss of one system would allow operations to continue, the loss of both systems would require the mission to be aborted. Repair parts for the new system are expensive although they have a significantly greater MTBF. Yet, maintaining in the part as an onboard spare would significantly increase the total system cost per vessel. This case study investigates various strategies to optimize the reliability and associated cost. The approach used in the case study may be useful in estimating cost versus reliability.