Historical failure data show some sixty percent of integrated circuit failures can be traced to inadequate provision for heat dissipation. Improving avionics reliability requires finding regions of undue thermal resistance in the cooling air path from the dedicated vapor cycle environmental control system through supply ducting, rack, shelf, cage, card to component case. The imperative is control of the component case temperature. Several options can be applied to reducing any high thermal resistance found and optimal approaches will be traded off for cost effective performance. Additionally, from data on the forcing shock/vibration spectra, at the equipment bay, we will specify isolation provisions. Other considerations to be traded-off vs. Selection criteria involve wiring, connectors, EMI prevention and shielding against EMP. The objective of phase I is to arrive at a comprehensive set of design requirements for a prototype rack system providing a benign environment and thereby directed to improve reliability of racked avionics. This will be done through systems engineering and trade-off methods outlined herein.
