ACR LGT TAIL STRIKE ON TKOF PROC.

Narrative

PROB: AT V1 THE NOSE OF THE ACFT ABRUPTLY PITCHED UP WITHOUT ME INITIATING THE TKOF ROTATION. DURING THE INITIAL PORTION OF THE TKOF ROLL; THE ACFT BEGAN A BOUNCING MOTION; VERY SIMILAR TO THAT OF TAKING OFF ON A VERY ROUGH RWY. I MADE THE COMMENT TO THE FO THAT I DIDN'T THINK OF RWY 27R AS BEING A ROUGH RWY. HE ACKNOWLEDGED THAT HE DIDN'T THINK SO EITHER. I APPLIED FORWARD PRESSURE ON THE YOKE AND AS THE ACFT CONTINUED TO ACCELERATE; THE BOUNCING DIMINISHED. I CHKED THE AIRSPD INDICATOR AND SAW IT ALMOST AT THE V1 BUG SETTING OF 128 KTS. I STARTED TO RELAX SOME OF THE FORWARD YOKE PRESSURE AND LOOKED OUTSIDE IN PREPARATION FOR THE TKOF ROTATION. THE ACFT HAD PITCHED UP TO A NOSE HIGH ATTITUDE. I COULD NOT SEE THE RWY. THE ACFT FELT LIKE IT WAS AIRBORNE BUT IN STAGNATED FLT. THIS WAS SOON FOLLOWED BY A SETTLING FEELING. I APPLIED FULL PWR AND LOWERED THE NOSE SLIGHTLY. THE ACFT BEGAN TO ACCELERATE AND CLB. THE REMAINDER OF THE TKOF WAS NORMAL. AFTER WE LEVELED OFF AT OUR ASSIGNED ALT OF 5000 FT; THE AFT FLT ATTENDANT CALLED ON THE INTERPHONE AND SAID SHE BELIEVED A TAIL STRIKE HAD OCCURRED. THE FO AND I DISCUSSED THE SIT AND DECIDED TO RETURN TO FLL AND HAVE MAINT CHK THE TAIL'S CONDITION. I MANUALLY FLEW THE RWY 27R ILS APCH IN VFR CONDITIONS. THE LNDG AND TAXI TO THE GATE WERE NORMAL. I CANNOT EXPLAIN WHY THE ACFT BEGAN A BOUNCING MOTION DURING THE TKOF ROLL. IT WAS UNUSUAL ENOUGH THAT I CONSIDERED ABORTING THE TKOF BUT THE BOUNCING DIMINISHED AS WE CONTINUED TO ACCELERATE AND I FELT WE HAD RETURNED TO A NEAR NORMAL TKOF CONDITION. IT IS MY OPINION THAT WHAT HAPPENED DURING THE INITIAL PORTION OF THE TKOF IS DIRECTLY RELATED TO WHAT OCCURRED AT V1. I BELIEVE THE BOUNCING MOTION RETURNED WHEN I RELEASED THE FORWARD YOKE PRESSURE AT V1. THE RESULTING UPWARD MOTION OF THE NOSE STRUT; COMBINED WITH BEING AT NEAR FLYING SPD; CAUSED THE NOSE TO PITCH UP AND THE PREMATURE ROTATION. SUPPLEMENTAL INFORMATION FROM ACN 253224: DURING THE DISCUSSION TO RETURN TO FLL; WE WERE TO LEVEL AT 16000 FT. ATC INSTRUCTIONS TO TURN L AND PROCEED DIRECT TO FLL AND DSND TO 10000 FT WERE GIVEN AND SET INTO AUTOPLT CTLS. ACFT CLBED TO 16350 FT BEFORE I UNCOUPLED AUTOPLT AND STARTED DSCNT.