Designing factory support equipment for field use

One problem that continues to plague test equipment is the fact that the factory, depot and field are all different environments, creating a scenario where the Unit Under Test (UUT) is being tested under variable circumstances. Additionally, the amount of testing available to the field is often limited to the extent that the field test equipment is only capable of determining a most likely Line Replaceable Unit (LRU) to swap out. When a swap-out action remediates a given problem, the replaced item is assumed to be faulty and the LRU is sent back to the depot for further repair. The all-too-common sequence of events following this field repair is that the depot receives the failed LRU, subjects it to further testing to determine the repair action to take, and finds that the failure experienced in the field is no longer present in the LRU. The LRU is then returned to supply, labeled as being in working condition, and ultimately returned to the field where it quickly fails yet again and is recycled through the system until the depot detects what is commonly referred to as a “hard” failure. A “hard” failure is an “environment agnostic” failure that can be detected when the UUT is returned from the field environment and subjected to higher quality testing back at the depot. It has been recognized that one of the keys to solving this problem is providing depot or factory-quality testing in the field that can provide initial diagnosis prior to the failed UUT ever returning to the depot. While various approaches have been taken to remove this variability of test pass and failure, many of these approaches ultimately fail to deliver the intended results due to logistics issues including lack of portability, overbearing cost for additional development, and lack of field-deployable personnel who are equipped to better troubleshoot equipment. This paper presents an approach to designing test equipment where factory-quality equipment is developed with reuse for the field in mind. By taking advantage of commercial-off-the-shelf (COTS) hardware operating on the right busses and software design patterns that support high levels of flexibility and reuse, the field can be equipped to provide factory-level testing with its associated quality of data while minimizing cost and logistics impacts beyond those initially incurred for factory-level development.