Narrative:

The captain and I were originating flight from sacramento. This was to be the first flight after a bird strike was noted in the logbook and corrective action was taken by contract maintenance. During the preflight, I noticed feathers on the ramp near the #2 engine where maintenance had extracted bird's remains. Ramp illumination was at best dim, so I conducted my preflight with a flashlight as is my usual practice on morning originators. I carefully checked each fan blade for damage by directing light from my flashlight towards the engine inlet, paying particular attention to the condition of the fan leading edges (looking for tears or bends consistent with damage from a bird ingestion). I looked through the fan blades at the fixed stators and examined the fan exhaust from the rear of the cowling. I did not notice any bent metal or light reflecting back at me that would indicate debris or blockage to the movement of air through the engine. Incidentally, this is exactly how I have preflted the internal components of the engine on every company preflight. The remainder of the preflight and the steps leading to the taxi out for takeoff were uneventful. We again discussed the fact that we were on the first flight after a bird strike while we were approaching the runway. I mentioned that it may have been more than 1 bird based on the bird parts I had seen on the ramp (apparently extracted the night before). We actually went as far as reviewing the abort procedure and the requirement to continue the takeoff after V1, even if we hear a loud noise. This is normal procedure, rarely discussed prior to the typical departure. In short, we were waiting for the engine to fail. As we brought the power up for departure, passing approximately 88% N1, we heard at least 1 loud bang, there may have been 2 or 3. It (they) were loud enough that it was clear to both pilots that we were not going to continue the takeoff. The captain aborted at approximately 50 KTS. We notified tower, cleared the runway, ran the rejected takeoff checklist, including evaluating brake energy and, after a pause to notify the passenger and ground control, returned to the gate. We were confident that we had heard a compressor stall and so we examined the #2 engine at the gate. It was now later and the ramp was better illuminated. By reaching into the engine inlet and moving the fan, the captain was able to notice approximately 3 gray feather quills (approximately 1/8 inch in diameter) that were wrapped around the fixed stators at their most radically outboard location. Finding them required moving the fan to various position and shining a flashlight in daylight at their exact position. It is unclr if the engine compressor stalled because of the feather quills on the stators. What is clear is that the engine was not perfectly cleaned prior to flight. While I believe that the cleaning of the engine is clearly a maintenance function, it is possible that a more diligent preflight of the engine (sitting in the engine inlet and both illuminating and possibly running a finger along the stators) might have brought more attention to the problem. In short, if both pilots with tens of thousands of combined hours of experience have a gut feeling that there is a good chance of an engine problem during takeoff, then the procedure of signing off an engine after a bird strike with only the requirement of a borescope within 10 cycles might need to be re-evaluated. A full power run, for example, would have eliminated this event. I know now how I will be preflting the next 'fodded' engine -- now that I know what to look for. Supplemental information from acn 604583: the logbook was documented with a postflt bird inspection and maintenance note that the aircraft was safe to fly 10 flight cycles prior to borescope inspection on #2 engine. My postflt inspection revealed a contaminated ramp with bird parts and at least 4 large 6-8 inch feathers on the fixed stators to #2 engine. Prevention: a more efficient bird inspection/clean-up by mechanic. Investigate ability to fly 10 flight cycles prior to borescope of engine, with known engine ingestion of birds!

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Original NASA ASRS Text

Title: B737-700 CREW HAD A SERIES OF COMPRESSOR STALLS ON TKOF ROLL. THE ACFT WAS WRITTEN UP FOR BIRD STRIKES BY THE INBOUND CREW.

Narrative: THE CAPT AND I WERE ORIGINATING FLT FROM SACRAMENTO. THIS WAS TO BE THE FIRST FLT AFTER A BIRD STRIKE WAS NOTED IN THE LOGBOOK AND CORRECTIVE ACTION WAS TAKEN BY CONTRACT MAINT. DURING THE PREFLT, I NOTICED FEATHERS ON THE RAMP NEAR THE #2 ENG WHERE MAINT HAD EXTRACTED BIRD'S REMAINS. RAMP ILLUMINATION WAS AT BEST DIM, SO I CONDUCTED MY PREFLT WITH A FLASHLIGHT AS IS MY USUAL PRACTICE ON MORNING ORIGINATORS. I CAREFULLY CHKED EACH FAN BLADE FOR DAMAGE BY DIRECTING LIGHT FROM MY FLASHLIGHT TOWARDS THE ENG INLET, PAYING PARTICULAR ATTN TO THE CONDITION OF THE FAN LEADING EDGES (LOOKING FOR TEARS OR BENDS CONSISTENT WITH DAMAGE FROM A BIRD INGESTION). I LOOKED THROUGH THE FAN BLADES AT THE FIXED STATORS AND EXAMINED THE FAN EXHAUST FROM THE REAR OF THE COWLING. I DID NOT NOTICE ANY BENT METAL OR LIGHT REFLECTING BACK AT ME THAT WOULD INDICATE DEBRIS OR BLOCKAGE TO THE MOVEMENT OF AIR THROUGH THE ENG. INCIDENTALLY, THIS IS EXACTLY HOW I HAVE PREFLTED THE INTERNAL COMPONENTS OF THE ENG ON EVERY COMPANY PREFLT. THE REMAINDER OF THE PREFLT AND THE STEPS LEADING TO THE TAXI OUT FOR TKOF WERE UNEVENTFUL. WE AGAIN DISCUSSED THE FACT THAT WE WERE ON THE FIRST FLT AFTER A BIRD STRIKE WHILE WE WERE APCHING THE RWY. I MENTIONED THAT IT MAY HAVE BEEN MORE THAN 1 BIRD BASED ON THE BIRD PARTS I HAD SEEN ON THE RAMP (APPARENTLY EXTRACTED THE NIGHT BEFORE). WE ACTUALLY WENT AS FAR AS REVIEWING THE ABORT PROC AND THE REQUIREMENT TO CONTINUE THE TKOF AFTER V1, EVEN IF WE HEAR A LOUD NOISE. THIS IS NORMAL PROC, RARELY DISCUSSED PRIOR TO THE TYPICAL DEP. IN SHORT, WE WERE WAITING FOR THE ENG TO FAIL. AS WE BROUGHT THE PWR UP FOR DEP, PASSING APPROX 88% N1, WE HEARD AT LEAST 1 LOUD BANG, THERE MAY HAVE BEEN 2 OR 3. IT (THEY) WERE LOUD ENOUGH THAT IT WAS CLR TO BOTH PLTS THAT WE WERE NOT GOING TO CONTINUE THE TKOF. THE CAPT ABORTED AT APPROX 50 KTS. WE NOTIFIED TWR, CLRED THE RWY, RAN THE REJECTED TKOF CHKLIST, INCLUDING EVALUATING BRAKE ENERGY AND, AFTER A PAUSE TO NOTIFY THE PAX AND GND CTL, RETURNED TO THE GATE. WE WERE CONFIDENT THAT WE HAD HEARD A COMPRESSOR STALL AND SO WE EXAMINED THE #2 ENG AT THE GATE. IT WAS NOW LATER AND THE RAMP WAS BETTER ILLUMINATED. BY REACHING INTO THE ENG INLET AND MOVING THE FAN, THE CAPT WAS ABLE TO NOTICE APPROX 3 GRAY FEATHER QUILLS (APPROX 1/8 INCH IN DIAMETER) THAT WERE WRAPPED AROUND THE FIXED STATORS AT THEIR MOST RADICALLY OUTBOARD LOCATION. FINDING THEM REQUIRED MOVING THE FAN TO VARIOUS POS AND SHINING A FLASHLIGHT IN DAYLIGHT AT THEIR EXACT POS. IT IS UNCLR IF THE ENG COMPRESSOR STALLED BECAUSE OF THE FEATHER QUILLS ON THE STATORS. WHAT IS CLR IS THAT THE ENG WAS NOT PERFECTLY CLEANED PRIOR TO FLT. WHILE I BELIEVE THAT THE CLEANING OF THE ENG IS CLRLY A MAINT FUNCTION, IT IS POSSIBLE THAT A MORE DILIGENT PREFLT OF THE ENG (SITTING IN THE ENG INLET AND BOTH ILLUMINATING AND POSSIBLY RUNNING A FINGER ALONG THE STATORS) MIGHT HAVE BROUGHT MORE ATTN TO THE PROB. IN SHORT, IF BOTH PLTS WITH TENS OF THOUSANDS OF COMBINED HRS OF EXPERIENCE HAVE A GUT FEELING THAT THERE IS A GOOD CHANCE OF AN ENG PROB DURING TKOF, THEN THE PROC OF SIGNING OFF AN ENG AFTER A BIRD STRIKE WITH ONLY THE REQUIREMENT OF A BORESCOPE WITHIN 10 CYCLES MIGHT NEED TO BE RE-EVALUATED. A FULL PWR RUN, FOR EXAMPLE, WOULD HAVE ELIMINATED THIS EVENT. I KNOW NOW HOW I WILL BE PREFLTING THE NEXT 'FODDED' ENG -- NOW THAT I KNOW WHAT TO LOOK FOR. SUPPLEMENTAL INFO FROM ACN 604583: THE LOGBOOK WAS DOCUMENTED WITH A POSTFLT BIRD INSPECTION AND MAINT NOTE THAT THE ACFT WAS SAFE TO FLY 10 FLT CYCLES PRIOR TO BORESCOPE INSPECTION ON #2 ENG. MY POSTFLT INSPECTION REVEALED A CONTAMINATED RAMP WITH BIRD PARTS AND AT LEAST 4 LARGE 6-8 INCH FEATHERS ON THE FIXED STATORS TO #2 ENG. PREVENTION: A MORE EFFICIENT BIRD INSPECTION/CLEAN-UP BY MECH. INVESTIGATE ABILITY TO FLY 10 FLT CYCLES PRIOR TO BORESCOPE OF ENG, WITH KNOWN ENG INGESTION OF BIRDS!

Data retrieved from NASA's ASRS site as of July 2007 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.