AERODYNAMIC SURFACE QUALITY
Aerodynamic Smoothness and Surface Restoration
General evaluation principles for aerodynamic smoothness, contour and exterior repair finish.
Key reference points
- Classify the aerodynamic zone before evaluation.
- Measure steps, gaps and waviness with the specified method.
- Fairing compound restores contour, not structural strength.
Organised training notes
1Classify the surface zone
Use the aircraft-defined aerodynamic zone before evaluating a dent, waviness, step, gap or external repair.
- 1.1 Extra-critical areaAreas affecting instruments, local lift, thrust or high drag can have the most restrictive smoothness requirements.
- 1.2 Critical areaThe approved data defines tighter contour control where local airflow is important.
- 1.3 Other exterior areaA less sensitive location still requires the stated structural, sealing and finish limits.
2Measure the actual condition
Use the specified straightedge, template, gauge or profile method across the defined measurement direction and span.
- 2.1 Local discontinuityIdentify steps, gaps, fastener-head condition and abrupt repair edges separately from broad waviness.
- 2.2 Waviness or dentRecord depth, length, width and spacing using the aircraft-defined datum and method.
3Restore only as approved
A smoother or fairing compound may restore contour but does not replace structural repair, sealing or protection.
- 3.1 Repair edgeUse the approved taper, chamfer, sealing and finish arrangement for the repair design.
- 3.2 Final inspectionConfirm contour, adhesion, drainage, finish and required functional or aerodynamic checks before release.
Training-reference boundary
This summary is not approved repair or maintenance data. Do not inspect, classify, select material, alter structure or perform a repair from this page alone. Use the current applicable SRM, AMM, engineering order, drawing and company procedures.