A LEARJET 35 ON TKOF ROLL AT 80 KTS BEGAN DRIFTING TO THE L THEN ABRUPTLY VEERED TO THE L STRIKING TWO RWY LIGHTS.

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ON 06/FRI/04 AT APPROX XA35 LCL AT ZZZ ARPT I WAS THE NFP CAPT. THE FP; ALSO CAPT WITH MY COMPANY; ON TKOF RWY XX AT ABOUT 80 KT CALL-OUT; THE ACFT BEGAN DRIFTING AND THEN ABRUPTLY VEERED TO THE L. THE PF RELEASED THE NOSEWHEEL STEERING CTL AND USED R RUDDER AND AILERON TO GAIN BACK CTL AND RETURN TO THE NEAR CTRLINE BY LIFT-OFF. ACFT APPARENTLY CONTACTED TWO RWY LIGHT STANCHIONS CAUSING A LARGE DENT IN THE LEAR 35'S L TIP TANK. THIS WENT UNNOTICED BY THE FLT AND CABIN CREW WHO NEITHER FELT OR HEARD ANYTHING UNUSUAL. AFTER SUCCESSFUL COMPLETION OF TKOF AND LNDG 40 MINS LATER AT ZZZ1 WE WERE MADE AWARE OF SOME UNDETERMINED STRIKE OF SOME NATURE ON L TIP TANK. WE THEN PHONED BOTH THE ZZZ1 AND ZZZ CTL TWRS TO INQUIRE ABOUT ANY RPTED FOD OR RWY LIGHTS ETC THAT HAD BEEN DAMAGED. WE WERE TOLD BY BOTH TWRS THAT AT OUR REQUEST RWYS HAD BEEN CHKED AND NO RPTED DAMAGE WAS FOUND. WE THEN SUSPECTED AN AIRBORNE STRIKE OF AN UNDETERMINED NATURE. AGAIN WE CALLED BOTH TWRS AND GAVE THEM OUR CELL PHONE # AND PROCEEDED TO A LABORATORY FOR A VOLUNTARY DRUG AND ALCOHOL TEST. WHILE RETURNING TO THE ARPT WE RECEIVED A CALL FROM THE SUPVR AT THE ZZZ TWR INFORMING US THAT THE STATE HAD DISCOVERED TWO DAMAGED RWY LIGHTS. AT THAT POINT OF APPARENT UNEXPLAINABLE DRIFTING/VEERING ACTION I QUICKLY MENTALLY REVIEWED POSSIBILITIES OF L MAIN GEAR FLAT TIRE; A HUNG-UP BRAKE; OR FOD; OR POSSIBLE FLT CTL PROB WITH TRIM OR RUDDER. BECAUSE OF PREVIOUS HISTORY WITH LEARJET STEERING PROBS; I FELT THAT WAS THE BEST POSSIBLE EXPLANATION. AN ABORT TKOF IN MY OPINION AT THAT TIME WOULD HAVE CAUSED A SEVERE ACCIDENT. INSTEAD THE CORRECTIVE ACTION INCLUDED STRONGER RUDDER AND AILERON INPUT. ADDITIONALLY; THE PF RELEASED NOSEWHEEL STEERING. AFTER CAREFUL REVIEW OF ALL FACTORS SURROUNDING THIS INCIDENT I BELIEVE THAT THE NOSEWHEEL STEERING ON THIS ACFT COULD BE MODIFIED AND A LOOK AT HOW MANY SIMILAR LEARJET STEERING PROBS HAVE BEEN RPTED TO NASA OR THE LEARJET FACTORY.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE NOSEWHEEL STEERING WAS TESTED ON THE GND AT LOW SPEED AND HIGH SPEED AND FOUND MALFUNCTIONING. THE RPTR SAID THE STEERING BOX AND STEERING SERVO WERE REPLACED. THE RPTR STATED THE LEARJET 35 STEERING SYS IS TOO SENSITIVE AND HARD TO ADJUST AT HIGH SPEEDS. THE RPTR SAID MANY SERVICE DIFFICULTY RPTS HAVE BEEN SENT TO THE MANUFACTURER ON THE NOSEWHEEL STEERING SYS.SUPPLEMENTAL INFO FROM ACN 620032: I FEEL THE NOSEWHEEL STEERING SYSTEM IN LEAR 20/30 SERIES COULD HAVE A BETTER STEERING AUTHORITY SYSTEM FOR ADJUSTMENTS/FINE TUNING. I'VE EXPERIENCED MANY STEERING ISSUES WITH THE CURRENT SYSTEM CAUSING OCCURRENCES IN THE TKOF ROLL TO VEER FROM CTRLINE.