Narrative:

Flight pushed from gate with a wheels-up time of xx. ATC strongly advised us that an earlier wheels-up time was imminent, so we pushed at the xx time. The delayed engine procedure was utilized, and during taxi we received the ACARS takeoff. Pitch attitude of 15 degree (3 engine climb). Takeoff EPR reduced at 190/192/190 which we used and a stabilizer trim of 6.1. The takeoff roll was normal and no sign of wind shear was evident. I was flying and at V1/vr initiated a normal rotate of 2 to 3 degree per second to 15 degree pitch attitude, as per sopa criteria. Immediately after liftoff I heard a faint noise which I thought resembled the gear strut extension. So informed me that the tail skid light was still illuminated. We assumed that the skid had been struck and we went to the book for the procedure and followed it. Both dispatch and ord maintenance were informed as to our situation and we chose to proceed to our destination. We made the approach at ord, runway 9R, and landed normally with no further incident. In reviewing, the ACARS weight tab given us at departure and the tab we procured at our destination from the computer showed a difference of 400 pounds due to, apparently, 2 additional passenger boarding late. A minor difference, but never transmitted to us. Other than this, all the weights, numbers, speeds, takeoff and rotation procedures were according to sopa and can be attested to by myself, first officer, and so. In conclusion, the large transport with XXX engines, when new, was an underpwred aircraft, and now after yrs of use and thousands of engine cycles, these engines do not develop the same power and thrust numbers represented in the quick reference manual, especially at reduced EPR. It is my recommendation, if you will, to eliminate reduced power settings and/or slow the rotation rate to 2 degree per second maximum (as opposed to 2-3 degree per second per sopa) until there is further investigation.

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Original NASA ASRS Text

Title: CAPT FLYING LGT HIT TAIL SKID ON ROTATION.

Narrative: FLT PUSHED FROM GATE WITH A WHEELS-UP TIME OF XX. ATC STRONGLY ADVISED US THAT AN EARLIER WHEELS-UP TIME WAS IMMINENT, SO WE PUSHED AT THE XX TIME. THE DELAYED ENG PROC WAS UTILIZED, AND DURING TAXI WE RECEIVED THE ACARS TKOF. PITCH ATTITUDE OF 15 DEG (3 ENG CLB). TKOF EPR REDUCED AT 190/192/190 WHICH WE USED AND A STABILIZER TRIM OF 6.1. THE TKOF ROLL WAS NORMAL AND NO SIGN OF WIND SHEAR WAS EVIDENT. I WAS FLYING AND AT V1/VR INITIATED A NORMAL ROTATE OF 2 TO 3 DEG PER SECOND TO 15 DEG PITCH ATTITUDE, AS PER SOPA CRITERIA. IMMEDIATELY AFTER LIFTOFF I HEARD A FAINT NOISE WHICH I THOUGHT RESEMBLED THE GEAR STRUT EXTENSION. SO INFORMED ME THAT THE TAIL SKID LIGHT WAS STILL ILLUMINATED. WE ASSUMED THAT THE SKID HAD BEEN STRUCK AND WE WENT TO THE BOOK FOR THE PROC AND FOLLOWED IT. BOTH DISPATCH AND ORD MAINT WERE INFORMED AS TO OUR SITUATION AND WE CHOSE TO PROCEED TO OUR DEST. WE MADE THE APCH AT ORD, RWY 9R, AND LANDED NORMALLY WITH NO FURTHER INCIDENT. IN REVIEWING, THE ACARS WT TAB GIVEN US AT DEP AND THE TAB WE PROCURED AT OUR DEST FROM THE COMPUTER SHOWED A DIFFERENCE OF 400 POUNDS DUE TO, APPARENTLY, 2 ADDITIONAL PAX BOARDING LATE. A MINOR DIFFERENCE, BUT NEVER XMITTED TO US. OTHER THAN THIS, ALL THE WTS, NUMBERS, SPDS, TKOF AND ROTATION PROCS WERE ACCORDING TO SOPA AND CAN BE ATTESTED TO BY MYSELF, FO, AND SO. IN CONCLUSION, THE LGT WITH XXX ENGS, WHEN NEW, WAS AN UNDERPWRED ACFT, AND NOW AFTER YRS OF USE AND THOUSANDS OF ENG CYCLES, THESE ENGS DO NOT DEVELOP THE SAME PWR AND THRUST NUMBERS REPRESENTED IN THE QUICK REF MANUAL, ESPECIALLY AT REDUCED EPR. IT IS MY RECOMMENDATION, IF YOU WILL, TO ELIMINATE REDUCED PWR SETTINGS AND/OR SLOW THE ROTATION RATE TO 2 DEG PER SECOND MAX (AS OPPOSED TO 2-3 DEG PER SECOND PER SOPA) UNTIL THERE IS FURTHER INVESTIGATION.

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.