Safety, reliability, maintainability and quality requirements need defined acceptance criteria and evidence a reviewer can trace. STi supports systems engineering, configuration management, integration, test and independent verification and validation across that lifecycle.
An assurance conclusion is only as sound as its basis. The configuration examined, operating conditions, model structure, data pedigree and unresolved assumptions must be visible. A calculated result, a passing test and a closed finding answer different questions; effective technical review keeps those distinctions clear.
- Reliability, maintainability and safety engineering
- Systems-engineering and configuration interfaces
- Test, evaluation and independent verification and validation
- Quality assurance, technical review and objective evidence
Start with the function and the consequence.
Failure modes and effects analysis (FMEA) examines how an item can fail and what those failures do at successive system levels. Adding criticality analysis produces FMECA, providing a basis for prioritization. Fault tree analysis (FTA) approaches a defined undesired event from the other direction, examining combinations of contributors and the assumptions that connect them.
The methods are complementary rather than interchangeable. Scope, system boundaries, operating modes and interfaces determine what an analysis can conclude. Safety decisions also require the designated risk-acceptance authority; a contractor’s analytical finding does not itself accept the customer’s risk.
Make reliability models explain the real architecture.
A reliability block diagram (RBD) represents the functional success logic of the system. Redundancy, switching behavior, common dependencies and operating phases influence whether the model reflects actual performance. Component predictions need a stated environment, stress basis, data source and treatment of uncertainty.
A reliability prediction estimates performance under stated operating and modeling assumptions. Technical review should examine whether the model fits the architecture, whether its inputs are defensible and whether sensitivity changes the engineering decision.
Evaluate electrical and design margins in context.
STi’s engineering experience includes worst-case circuit analysis (WCCA), reliability prediction, stress analysis and requirements assessment. A worst-case evaluation examines whether component tolerances and relevant operating variation can move a circuit beyond a required limit. Derating and stress considerations address a related but different question: how the application uses the component relative to its limits.
The assessment must identify the actual configuration, relevant operating conditions and acceptance criteria. A worksheet detached from the applicable design revision cannot establish confidence in the item being reviewed.
Plan verification and validation as different activities.
Verification establishes evidence against specified requirements. Validation examines whether the resulting system supports its intended use in the intended environment. A traceable plan connects each requirement to an appropriate method—analysis, inspection, demonstration or test—and defines an acceptable result.
STi’s IV&V services include strategy, test-event planning, execution support, data quality and reporting. Independence, witness responsibilities, test-article configuration, anomaly handling and review authority should be clear before the event, not reconstructed afterward.
Carry the evidence into a controlled decision.
Quality assurance considers the process that produces the result as well as the result itself. Review records should identify the issue, applicable requirement, evidence examined, technical disposition and closure status. Unresolved assumptions and limitations belong with the conclusion.
Configuration changes can affect earlier analyses, tests and safety findings. A disciplined change review asks which evidence remains applicable and which must be revisited. That connection between configuration and assurance is essential to sustain confidence after the initial review.
FROM METHOD TO EVIDENCE
Work products with a purpose.
- Requirements and verification traceability
- Reliability, maintainability and safety-analysis inputs or reviews
- Test strategy, event plans and evidence summaries
- Technical findings, limitations and discrepancy-closure records
- Configuration-impact and assurance-review recommendations
TECHNICAL INTERFACES
The work between disciplines.
- Systems and design engineering
- Customer quality and safety authorities
- Test organizations and configuration management
- Program leadership and risk decision-makers
A CLOSER LOOK
Questions that shape the work.
How do prediction and demonstrated evidence contribute to reliability decisions?
A prediction estimates performance from a stated model and inputs. Test or field evidence has its own configuration, conditions and data basis. Technical review explains how each contributes to the conclusion and where uncertainty remains.
What makes an IV&V result useful to an acquisition decision?
Traceability to requirements, a known test or analysis configuration, defined acceptance criteria, quality-controlled data and a clear account of anomalies, limitations and unresolved findings.
CONNECT THE REQUIREMENT TO THE RIGHT DISCIPLINE