Preparation for systems testing

The first, and most important, stage of systems testing is to determine the exact operational requirements. In other words what precisely is needed from the system to allow the pilot or operator to achieve the task or mission. The word precisely is important here because it is not just a question of defining the function that the system must meet but also defining the degree of accuracy required. Taking the example of a navigation system, the test team needs to understand what information the pilot will need (heading to steer, time to go, ETA, track error), at what point in the mission each item of information will be required, what the crew need to do with the information, and to what degree of accuracy the navigational information will be required. Staying with the last point, it is clear that if the navigation system feeds into an on-board weapon system a higher degree of accuracy will be required than if the information is only required for steering information by the crew. Similarly the accuracy needed in an air data system will also need to be higher if it has an input into the firing solution of a gun system.

Once the operational need is clearly understood a thorough understanding of the system under evaluation is needed. Part of the process is for the test operator to

become proficient in its use. Becoming fully ‘worked-up’ can prove difficult with new systems as the training material and system documentation are sometimes not available. However, allowing sufficient time to achieve proficiency is included in the test planning. The effect of partial and total system failure is also addressed during the preparatory stage by conducting a failure modes, effects and criticality analysis (FMECA).

Armed with an understanding of the operational requirements and knowledge of the system itself the test planning takes place. As with all testing the aim is to evaluate the system as comprehensively as possible under operationally realistic conditions. The facilities required to conduct the programme will vary according to the system but this type of testing can often require complex instrumentation and significant external resources such as ranges, airspace and radar targets.