The New Standard of Prognostic and Diagnostic Testing in Critical Systems
Ridgetop Group’s NightHawk™ NFF Reduction Tool is an interactive tool suite combining data and information management with advanced data analysis techniques serving to address root cause, reduce, and/or eliminate No Fault Found (NFF), “Could Not Duplicate” (CND), “Retest OK” (RTOK), and other similar issues related to Circuit Card Assemblies (CCAs) and modules on complex critical systems.
The root causes leading to NFF are linked to gaps in test coverage, operational usage conditions, and aging effects, which – due to their very nature – are difficult to identify using conventional approaches. NightHawk-based analysis improves the fault and test coverage of existing Test Program Sets (TPS), detecting soft faults on “Bad Actor” CCAs through the use of advanced anomaly detection algorithms.
A Conventional Problem and an Advanced Solution
There is a recognized need to improve the fault coverage of complex aerospace, automotive and complex industrial systems. Existing test program sets (TPSs) or test programs primarily examine functional test sequences of stimulus/response measurement instructions that are intended to determine whether the system is operating within specifications.
As systems age, component values can drift from their initial state, combining with other components that are also drifting, and cause an undetected “soft” fault to occur. These soft faults are not detectable using standard test methods, contributing to instances of “No Fault Found”, “Retest Okay”, “Could Not Duplicate” (CND) test escapes, or “Bounce Rate” when testing the system, causing major problems that conventional TPS are not equipped to handle.
In addition, some CCAs test fine in the depot, yet fail when installed into aircraft, making the need for an expanded “soft” fault test approach, like NightHawk, a necessary standard. To do this, Ridgetop has developed a proven solution, shown through NightHawk‘s design architecture, that builds upon typical ATE platform structures with an adaptive toolset, allowing for implementation within a multitude of systems.
NightHawk’s Intuitive Interface
Ridgetop’s NightHawk reduction tool employs user-friendly interactive interface that allow users to easily and accurately, identify and isolate difficult to find soft faults that carry the potential to cause critical mission failures. The user interface provides a mechanism to apply various algorithms for the detection and extraction of anomalies that are otherwise hidden from traditional testing processes.
NightHawk maximizes the benefit from investment in standard ATE platforms. In addition, NightHawk is a flexible and powerful companion software solution that is run on hardware ATE systems for soft fault detection and requires minimal or no new or specialized hardware.
NightHawk’s Features and Benefits
NightHawk improves the fault and test coverage of existing TPS and can now isolate and identify hard to find faults such as SIne Wave 1 and Sine Wave 2 distortion in waveform in addition to other multiple fault types , including:
- Stimulate the Unit Under Test (UUT) or Circuit Card Assembly
- Measure response to stimuli against limits (USL and LSL)
- Test Coverage, fault coverage metric exists
- Parametric variation of nominal values
- Intermittent and random metastable states in digital circuitry
- Noise-induced soft faults
- Most soft faults are not detectable using conventional tests
- Advanced anomaly detection algorithms are required
The NightHawk Algorithm library was developed for use in TPS for detection of degraded failure modes. They include:
- Frequency Response Analysis (FRA)
- Wavelet Haar Transform (WHT)
- Autocorrelation Analysis (ACA)
- Markov Chain
- Auto Associative Kernal Regression (AAKR)
- Critical Point Comparison (CPC)
NightHawk has already proven its adaptability through seamless integration with Test Platforms such as VDATS — over 100 ATE Systems are installed at Air Force Logistics bases — and is applicable to other agencies, ATE commercial fleet Maintenance Repair Overhaul (MRO) depots.
In addition, many commercial sectors, such as the industrial equipment and automotive sectors, can apply this tool to a variety of applications in those areas with NightHawk being able to reliably identify and test for soft fault NFFs in large operating equipment.