A Critical Task Independent Inspection (CTII) verifies the correct performance of safety-critical maintenance tasks.
• Incorporates GVI techniques to enhance the detection of visible defects, anomalies, and improper installations without intrusive disassembly.
• Authorized Person: Performs the critical maintenance task and releases the work after verification.
• Independent Qualified Person: Conducts an independent inspection to ensure the task was completed correctly and safely.
• Identify the critical task (e.g., flight controls rigging, engine mounts, calibration of systems).
• Reference applicable maintenance data (AMM, work cards, MSG-3 guidance).
• Inspection aids - High-quality flashlight, mirror, borescope (if needed)
• Checklists and task cards.
• Visual Inspection of Components to detect obvious defects, wear, or anomalies.
• Scan all parts of the assembly or installation systematically (top to bottom, left to right).
• Use a flashlight to illuminate hidden or shadowed areas.
• Cracks, deformation, or wear.
• Loose, missing, or damaged fasteners.
• Fluid leaks (stains, drips, streaks).
• Corrosion (discoloration, peeling, or pitting).
• Ensure components are securely mounted, aligned, and connected.
• Verify locking devices (e.g., safety wire, cotter pins) are intact and correctly installed.
• System Functional Verification to ensure components operate as intended.
• Verify systems (e.g., flight controls, cables) move freely and through the full range.
• Check for smooth operation without restriction or binding.
• Sense of Operation - Ensure the direction of movement is correct when input controls are activated.
• Measure cable tension against limits in the AMM.
• Inspect for clearance at secondary stops and confirm no interference with other systems.
Verify Hidden and Difficult-to-Reach Areas - Inspect critical but obscured components effectively.
• Mirror Inspection - Use mirrors to examine areas blocked by pipes, ducts, or structures.
• Borescope (Optional) - If required, use borescopes for difficult access areas, such as behind structures or within enclosed compartments.
Secondary Surfaces - Check surfaces adjacent to the primary inspection area for leaks, debris, or signs of vibration damage.
• Confirm safety wires, locks, and seals are installed correctly
• Safety wires are taut and correctly twisted.
• Critical fasteners are paint-marked for tamper evidence.
• Record Inspection Findings - Document results on appropriate work cards or technical logs.
• Note any defects, their locations, and reference limits exceeded.
• Include photographic evidence where applicable.
• An independent Qualified Person certifies the inspection completion.
• Authorized Person issues the Certificate of Release to Service (CRS).
• Lighting - Always use a high-lumen flashlight to spot anomalies in dim or shadowed areas.
• Systematic Approach - Divide the area into small sections for a focused, detailed inspection.
• Use of Visual Aids - Mirrors, borescopes, or magnifiers for small or obscured components.
• Focus on Interfaces - Pay special attention to connections between components, joints, and attachments.
• Perform inspections in a clean and quiet area to minimize distractions.
• Ensure clear communication:
• If only one person is available (e.g., remote locations), a self-reinspection may be performed following identical steps.
• Proper justification and documentation must accompany the reinspection record.
Sofema Aviation Services (SAS) and Sofema Online (SOL) provide classroom, webinar and regulatory training in support of EASA Part 145 including CAT A critical task inspection – please see the websites or email team@sassofia.com.
