Engine Surge Event – Internal Compressor Inspection and Rectification Process
Article ID: DYN-KA-ENG-INS-IPC-001
Category: Propulsion Systems → Compressor Module → Internal Damage / Surge Event
Version: 2.0 | Last Updated: October 2025
Summary
This article provides detailed technical guidance for diagnosing and resolving engine surge events resulting in internal compressor damage. It outlines the inspection standards, tolerances, and corrective actions following a high-speed rejected take-off, in-flight surge, or ground vibration incident.
The process is designed for Copilot-assisted troubleshooting and integrates automated logic for data capture, classification, and inspection recommendations.
Symptoms
- Loud bang, tailpipe flame, or smoke emission
- Engine stall or fail message on ECAM/EICAS
- High vibration levels (>2.5 ips peak)
- EGT rise exceeding 50°C delta over baseline
- Metallic debris or fragments found in tailpipe
Safety and Containment Actions
- Isolate affected engine and tag as AOG – Awaiting Inspection.
- Confirm extinguisher bottles and squibs are safe.
- Record event under Incident Type “Engine Surge / Compressor Damage”.
- Attach engine data: N1, N2, N3, EGT, VIB, FF.
- Notify Service Control Centre (SCC) and OEM support.
External Visual Inspection
Objective: Confirm no nacelle or external structural damage before internal inspection.
| Component | Allowable Deformation | Surface Damage Limit |
|---|---|---|
| Inlet Lip Skin | ≤ 1.0 mm deflection | Minor surface scoring permitted |
| Fan Case Outer Wall | ≤ 0.5 mm distortion | No cracking or blistering |
| Spinner | ≤ 0.3 mm runout | Paint loss allowed; no structural crack |
Internal Inspection – Borescope (BSI)
Objective: Identify internal damage in the Intermediate Pressure Compressor (IPC) or equivalent core section.
Access Points: IPC stages 1–8, plus optional HPC continuity checks.
| Parameter | Limit / Tolerance | Measurement Method |
|---|---|---|
| Leading Edge Nick | ≤ 0.25 mm deep | Visual + 10× magnification |
| Trailing Edge Tear | ≤ 2.0 mm length | Borescope image measurement |
| Surface Dent | ≤ 0.5 mm depth or ≤ 10 mm length | Depth gauge or digital cursor |
| Missing Material | ≤ 1.5% chord length | AI overlay comparison |
| Blade Twist / Deformation | ≤ 0.8° from datum | Optical comparator |
| Root Attachment Crack | None permitted | Fluorescent penetrant check |
| Platform Burn / Rub | Permitted up to 5 mm | Measured from edge limit line |
Intermediate Pressure Compressor (IPC) Evaluation
| Stage | Typical Finding | Action |
|---|---|---|
| IPC 1–2 | Minor surface rub or dust erosion | Clean and re-inspect |
| IPC 3–5 | Foreign object scoring or pitting | Minor blend if within limits |
| IPC 6–8 | Dents / missing material / tears | Replace if >1.5% chord loss or >2 mm depth |
Blending Notes: Maintain trailing edge thickness ≥ 0.40 mm; contour deviation ≤ ±0.15 mm from nominal.
Diagnostic Conclusion – Copilot Decision Path
| Finding | Copilot Outcome | Recommended Action |
|---|---|---|
| All within tolerance | Auto-close event | Return to service |
| One or more blades exceed limit | Escalate | Generate work order for module removal |
| Metallic debris detected | Containment required | Activate FOD checklist |
| Vibration trend abnormal | Further diagnostic | Schedule balance run-up test |
Corrective Actions
- If damage exceeds limits:
- Remove compressor module for bench inspection.
- Replace damaged blades per AMM guidelines.
- Perform rotor balance to ≤ 0.3 g·mm residual imbalance per stage.
- Conduct dimensional verification using precision metrology tools.
- If within limits:
- Blend and polish defects; maintain airflow recovery ≥ 98.5% baseline.
- Re-assemble and ground-run engine for vibration and EGT stability.
Post-Maintenance Verification
| Parameter | Acceptable Range | Verification Method |
|---|---|---|
| N2 Vibration | ≤ 1.2 ips peak | On-condition monitoring |
| EGT Stability | ±15°C deviation max | Trend comparison |
| Surge Margin | ≥ 3.0% | Performance analysis |
| Bearing Temp Rise | ≤ 25°C above ambient | Engine instrumentation |
Closure and Documentation
- Complete Return to Service (RTS) checklist in Dynamics.
- Attach:
- Borescope images
- Repair sheets
- Balance certificates
- Dimensional inspection reports
- Copilot generates event summary and updates asset history.
Status: Resolved – Internal Damage Rectified
Technical References
- AMM 72-31-10 – Compressor Module Inspection and Removal
- MP 72-08-03 – Compressor Blade Tolerance and Blending Procedure
- SB GEN-72-101 – Surge Event Inspection Standard
- ESM 05-12-02 – Engine Surge Diagnostic Flow
- ISO 1940-1 – Rotor Balance Quality Grade G2.5
Copilot Prompts and Intelligent Assistance
| Trigger Phrase | Copilot Response |
|---|---|
| "Run surge analysis" | Classifies event and identifies affected stage |
| "Analyse borescope footage" | Auto-tags defects and measures severity |
| "Generate FOD checklist" | Creates inspection tasks for intake and tailpipe |
| "Recommend repair action" | Suggests blend, replace, or module removal |
| "Summarise inspection findings" | Creates formatted inspection report |