Zonal Damage Evaluation

Zonal Damage Evaluation refers to the focused inspection and assessment of specific areas (zones) of an aircraft following incidents such as bird strikes, lightning strikes, ground handling damage, or other localized impacts. The goal is to accurately identify and characterize any damage and ensure proper corrective action is taken to restore the aircraft’s structural integrity and airworthiness.

Purpose

• Identify and quantify damage within affected zones.
• Assess the extent of damage relative to structural limits and regulatory guidelines.
• Ensure that all necessary repairs are performed correctly and comprehensively.
• Restore the airframe to its original strength and flight safety standards.

How It Works

• After an incident, maintenance teams perform visual and non-destructive inspections (NDI) in the suspected impact zone.
• Detailed documentation is created, including photographs, dimensions, and descriptions of all observed damage.
• Damage tolerance criteria and structural repair manuals (SRMs) guide the decision-making process for repairs or replacements.
• Follow-up inspections verify the effectiveness of completed repairs.

Applications

• Bird Strike Incidents: Evaluation of leading edges, radomes, wing structures, and windshields.
• Lightning Strikes: Inspection of wingtips, tail sections, fuselage panels, and bonding points for arcing or burn-through.
• Ground Damage: Examination of cargo doors, landing gear fairings, and lower fuselage zones.

Techniques Used

• Visual Inspection (VI)
• Ultrasonic Testing (UT)
• Eddy Current Testing (ET)
• Radiographic Inspection (X-ray)
• Thermography

Benefits

• Prevents undetected damage from compromising flight safety.
• Reduces unnecessary downtime by targeting inspections precisely.
• Supports compliance with manufacturer guidelines and regulatory standards.

Summary

Zonal damage evaluation is a critical maintenance process that ensures localized structural incidents are thoroughly assessed and repaired, preserving the overall safety, strength, and airworthiness of the aircraft.