When reviewing Non-Destructive Testing (NDT) reports, such as Radiographic Testing (RT) images, Infrared Thermography (IRT) data, and Ultrasonic Testing (UT) C-scans, the primary goal is to identify any defects or anomalies that were not initially identified or reported. This process ensures that all potential issues have been properly documented for further analysis or remediation. 

1. Radiographic Testing (RT) Images:

• Evaluate Image Quality: Ensure that the RT images are clear, well-exposed, and of high resolution. Poor-quality images can obscure defects, leading to false negatives.
• Inspect for Common Defects: Look for typical defects such as cracks, porosity, voids, inclusions, or weld discontinuities. Check whether these are identified in the report.
• Compare with Known Standards: Cross-reference the images with known defect standards and criteria to ensure any anomaly has been recorded. Verify the critical dimensions of identified defects (e.g., length, width, depth).
• Look for Overlooked Areas: Examine regions of the material or welds that were not fully captured in the RT images. Defects may exist in areas that were underexposed or misinterpreted.
• Check for Shadowing or Ghost Images: In RT, certain material properties or geometry can lead to shadowing or ghost images that might hide small defects.

2. Infrared Thermography (IRT) Data:

• Review Temperature Profiles: Ensure that temperature differences, which could indicate material defects, are properly interpreted. IRT often reveals thermal anomalies such as delaminations, air voids, and cracks.
• Cross-check with Known Defects: Confirm that the areas identified as problematic in the IRT data match known defect types (e.g., delaminations, voids, etc.).
• Check for Misinterpretations: IRT relies on thermal conductivity, which can be influenced by factors like the surface coating, material composition, or geometry. Ensure that the thermal data hasn’t been misinterpreted due to these variables.
• Thermal Signatures: Verify if thermal signatures have been correctly attributed to defects. Sometimes, benign surface irregularities or heat sources can be mistaken for actual defects.

3. Ultrasonic Testing (UT) C-Scans:

• Examine the C-scan Image: Review the C-scan image for indications of defects. Ensure that all areas of interest have been scanned and analyzed thoroughly.
• Look for Anomalous Signals: Verify the C-scan for any signals that might be missed or misinterpreted, such as lack of signal, reflection anomalies, or incomplete scans.
• Check the Depth of Penetration: Ensure that the UT testing has adequately penetrated the material thickness. Missed defects can be located in deeper layers, beyond the detectable range.
• Review Scan Coverage: Ensure that the entire area was scanned. Sometimes, scans may miss critical areas, especially in geometrically complex structures.
• Assess Amplitude and Time-of-Flight: Verify if the amplitude and time-of-flight measurements for detected indications are consistent with known defect characteristics, such as cracks, voids, or inclusions.

4. General Best Practices:

• Cross-Validation: When possible, cross-validate NDT results with other techniques. For example, if RT detects a possible defect, check IRT or UT for corroborating data.
• Consult with Experts: If uncertain about a particular indication, seek expert opinions. Misinterpretation of data can sometimes lead to missed defects.
• Ensure Adequate Coverage: Confirm that the entire inspection area has been scanned or imaged, especially in larger or more complex structures. Missing defects could result from insufficient coverage.
• Review Calibration and Settings: Double-check the calibration of NDT equipment to ensure that all tools were functioning optimally. Faulty calibration could lead to missed or inaccurate results.
• Compare with Previous Reports: If this review is part of ongoing maintenance or inspections, compare findings with previous NDT reports to ensure consistency and identify trends in defect development.