DC8-62 FREIGHTER MAKING A ROLLING TKOF; FO; PF; UNABLE TO MAINTAIN DIRECTIONAL CTL. CAPT BEGAN TO ABORT THE TKOF WITH THE ACFT ENDING OFF THE EDGE OF THE RWY WITH TAIL STILL ON THE RWY. FO SUSPECTS AFT CTR OF GRAVITY LIMITS PREVENTED THE NOSEWHEEL FROM BEING EFFECTIVE.

Narrative

DURING A ROLLING TKOF; ACFT CTL WAS GIVEN TO ME AFTER THE ACFT WAS ALIGNED WITH THE RWY CTRLINE AND THE ENGS SPOOLED UP TO APPROX 60-65%. I SMOOTHLY ADVANCED ALL THROTTLES UNTIL THE ENGS STABILIZED AT 80%. I THEN STARTED TO SLOWLY ADVANCE ALL THROTTLES TO THE REDUCED PWR TKOF SETTING. AS I DID THIS; THE ACFT STARTED TO DRIFT TO THE L AND I APPLIED FULL R RUDDER CORRECTION WITH NO RESULTING RESPONSE. THE RUDDER PEDALS SHOULD HAVE SOME INPUT TO THE NOSEWHEEL STEERING. I MADE SOME COMMENT ABOUT THIS TO THE CAPT AND HE WAS ALREADY IN THE PROCESS OF ABORTING THE TKOF. AFTER THE THROTTLES WERE RETARDED TO IDLE AND THE THRUST REVERSERS DEPLOYED; THE ACFT VEERED TO THE R AND WENT OFF THE RWY AT ABOUT 2200 FT FROM THE TKOF END. THE TAIL WAS STILL A FEW FT OVER THE RWY AFTER THE ACFT WAS STOPPED. EMER EQUIP WAS REQUESTED AND THE ENGS SHUT DOWN. THERE WERE NO FIRES OR ANY FURTHER DANGER. THE ACFT WAS TAIL HVY. ALTHOUGH IT WAS WITHIN THE AFT CTR OF GRAVITY LIMIT AND THE PWR WAS SMOOTHLY APPLIED; I THINK THE NOSE STRUT EXTENDED AND THE GND SHIFT WENT INTO THE FLT SHIFT MODE. THIS WOULD REMOVE RUDDER PEDAL COMMANDS TO THE NOSE STEERING AND ALLOW THE NOSE GEAR TO TURN IN ANY DIRECTION. THE ONLY THING I CAN THINK OF TO PREVENT A RECURRENCE OF THIS SIT IS TO NOT LOAD THE ACFT SO CLOSE TO THE AFT CTR OF GRAVITY LIMIT.