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B747 flight crew experiences possible bird strike shortly after gear retraction; which is confirmed by maintenance upon landing 14 hours later. The right side engines both had fan damage requiring replacement.
| Attributes | |
| ACN | 871581 |
| Time | |
| Date | 201001 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Takeoff |
| Component | |
| Aircraft Component | Fan |
| Person 1 | |
| Function | Captain Pilot Flying |
| Experience | Flight Crew Last 90 Days 80 Flight Crew Total 18000 Flight Crew Type 4000 |
| Person 2 | |
| Function | First Officer Pilot Not Flying |
| Experience | Flight Crew Last 90 Days 240 Flight Crew Total 8000 Flight Crew Type 4000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Inflight Event / Encounter Bird / Animal |
Narrative:
Flight time today was just under 14 hours. On takeoff during second segment climb a flock of small birds flew underneath the nose crossing our path from my left to right. With the size of our 747 we felt that we had to have hit some of them. My eyes were focused on the motors. The instrumentation for the motors never showed any indication of a problem. Gear and flap retraction were completed and after discussing it with the crew we decided to continue on to destination and just monitor everything carefully. At the 5 hour point in the flight fuel burn and time enroute matched the flight time exactly. At top of descent we were actually ahead on gas. We notified maintenance of the possible bird strike and had them do a thorough inspection. Damage was found in both the number 3 and 4 engines as well as to one of the flaps. My understanding is that both motors had about 5 bent fan blades each that needed to be replaced. This plane flew 14 hours without any vibration on those engines and no increase in fuel burn. Pretty amazing. The only thing that I would add to the diagnostic side of the departure would have been to have system maintenance monitor the engine parameters enroute with their equipment just to make sure that a vibration wasn't developing that wasn't being shown on our instrumentation.
Original NASA ASRS Text
Title: B747 flight crew experiences possible bird strike shortly after gear retraction; which is confirmed by maintenance upon landing 14 hours later. The right side engines both had fan damage requiring replacement.
Narrative: Flight time today was just under 14 hours. On takeoff during second segment climb a flock of small birds flew underneath the nose crossing our path from my left to right. With the size of our 747 we felt that we had to have hit some of them. My eyes were focused on the motors. The instrumentation for the motors never showed any indication of a problem. Gear and flap retraction were completed and after discussing it with the crew we decided to continue on to destination and just monitor everything carefully. At the 5 hour point in the flight fuel burn and time enroute matched the flight time exactly. At top of descent we were actually ahead on gas. We notified Maintenance of the possible bird strike and had them do a thorough inspection. Damage was found in both the number 3 and 4 engines as well as to one of the flaps. My understanding is that both motors had about 5 bent fan blades each that needed to be replaced. This plane flew 14 hours without any vibration on those engines and no increase in fuel burn. Pretty amazing. The only thing that I would add to the diagnostic side of the departure would have been to have system maintenance monitor the engine parameters enroute with their equipment just to make sure that a vibration wasn't developing that wasn't being shown on our instrumentation.
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.