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Mechanic reports that during completion of an engineering authorized (ea) 7th-stage bleed duct installation on #2 engine of an A320; an alternate test was performed instead of using the bleed leak test maintenance manual chapter referenced in the ea document. The intermediate pressure stage (ip) valve lower clamp separated; allowing hot bleed air to damage thrust reverser.
| Attributes | |
| ACN | 915803 |
| Time | |
| Date | 201010 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Compressor Bleed Valve |
| Person 1 | |
| Function | Technician |
| Qualification | Maintenance Airframe Maintenance Powerplant |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy |
Narrative:
During completion of an ea (engineering authorized) driven 7th stage bleed duct installation on graveyard shift; the duct coupling clamps were tightened by hand only; to approximately the required 85-in lbs. The bleed system leak test was not the one used per the amm (aircraft maintenance manual) reference printed in the ea. An alternate test was performed using back-driven ground bleed air; which would have excluded the leak integrity of only one of the four clamps during the test.mechanic did verify that all clamps were properly in position; with no duress caused by duct misalignment. The ip (intermediate pressure stage) check valve lower clamp was found separated (intact with the check valve) from the 7th stage bleed valve duct. This resulted in hot bleed air contacting and damaging the surrounding thrust reverser inner structure. ECAM reported a #2 eng bleed fault.mechanic did not utilize the correct bleed system operational test; opting for a simpler test to be performed. Maintenance personnel were dispatched to ZZZ to remove and replace the left thrust reverser. Suggest that the correct bleed system test be followed.
Original NASA ASRS Text
Title: Mechanic reports that during completion of an Engineering Authorized (EA) 7th-Stage bleed duct installation on #2 engine of an A320; an alternate test was performed instead of using the bleed leak Test Maintenance Manual chapter referenced in the EA document. The intermediate pressure stage (IP) valve lower clamp separated; allowing hot bleed air to damage thrust reverser.
Narrative: During completion of an EA (Engineering Authorized) driven 7th stage bleed duct installation on graveyard shift; the duct coupling clamps were tightened by hand only; to approximately the required 85-in lbs. The bleed system leak test was not the one used per the AMM (Aircraft Maintenance Manual) reference printed in the EA. An alternate test was performed using back-driven ground bleed air; which would have excluded the leak integrity of only one of the four clamps during the test.Mechanic did verify that ALL clamps were properly in position; with no duress caused by duct misalignment. The IP (Intermediate Pressure Stage) check valve lower clamp was found separated (intact with the check valve) from the 7th stage bleed valve duct. This resulted in hot bleed air contacting and damaging the surrounding thrust reverser inner structure. ECAM reported a #2 eng BLEED fault.Mechanic did not utilize the correct bleed system operational test; opting for a simpler test to be performed. Maintenance personnel were dispatched to ZZZ to remove and replace the left thrust reverser. Suggest that the correct bleed system test be followed.
Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.