Application of HALT for Standardization in Aerospace Systems: A Case Study of Relay Contactors

Abstract

There is practically no activity nowadays that is not framed, whether partly or totally, by standards viz. Government standards, Industry standards, Company standards, etc. Standardization not only helps in maximizing the compatibility, interoperability, repeatability, safety, and quality but also in minimizing the efforts and requirements of procurement, inventory, logistics, and maintenance activities. This paper deals with a case study in which it was required to use the same relay contactor part number in several different systems for use in the aerospace applications. Due to non-availability of aerospace-grade contactors, two COTS (Commercial-off-the-Shelf)-grade contactors having different part numbers were short-listed on the basis of technical specifications, make, availability, accessibility, and past usage history. However, both contactor types were found falling short to the end-use environmental specifications of some of the systems. Highly Accelerated Life Testing (HALT) was successfully utilized by applying various types of environmental stresses on several samples of the contactors to discover their design margins viz. operational and destruct margins. HALT results revealed that the discovered design limits of one contactor model were meeting the requirements of the system having the most harsh field use conditions and were much beyond its (contactor’s) datasheet specifications and the same was selected to be used across all the systems. Over a period of time, the contactor has been integrated into many of these systems and has been successfully used for aerospace applications validating the HALT results.