LOSS OF ACFT CTL DURING LNDG PROC.

Narrative

DEPARTED OTH AT APPROX XX40AM ON PART 135 AIR AMBULANCE TRANSFER IN A C-414A. EXECUTED A VOR DME 3 APCH. BROKE OUT AT ABOUT 3 TO 4 MI FROM ARPT AND LANDED STRAIGHT-IN ON RWY 3. NORMAL OPS UNTIL A FEW SECONDS AFTER TOUCHDOWN WHEN THE PLANE STARTED PULLING SHARPLY TO THE L. I PULLED THE PWR BACK TO IDLE AND TRIED TO CTL THE PULLING WITH BRAKES BUT THAT ONLY CAUSED A SHUTTER. I THEN REVERTED TO CTLING THE PLANE WITH A LOT OF DIFFERENTIAL PWR. SOMEHOW MANAGED TO KEEP THE PLANE ON THE RWY. BEING CONFUSED WITH WHAT HAPPENED AFTER COMING TO A STOP; I CHKED THAT I STILL HAD 3 GREEN LIGHTS FOR THE GEAR AND PROCEEDED FORWARD TO CHK THE BRAKES AND DIRECTIONAL CTL WHILE TAXIING OFF THE RWY. EVERYTHING OPERATED NORMALLY. I ASKED GND CTL IF HE SAW SMOKE OR ANYTHING ELSE UNUSUAL -- HE SAID NEGATIVE. I TAXIED IN TO DROP OFF THE PATIENT AND ASKED TO HAVE THE MECHS MEET ME AT THE PLANE. THE PATIENT ASKED IF THERE WAS AN ICING PROB ON THE RWY; BUT OTHER THAN THAT; DIDN'T SEEM TO BE AWARE OF ANY SERIOUS PROBS. THE MECHS PUT JACKS UNDER THE L WING AND NOTED THE SCISSOR ARM BROKE LOOSE AND THE TIRE HAD ROTATED 180 DEGS. I LATER FOUND OUT THAT THE SCISSOR ARM MAY HAVE BEEN ASSEMBLED INCORRECTLY. AN INVESTIGATION NOW SEEMS TO BE STARTED BY FAA TO SEE WHO AND WHY IT WAS PUT ON WRONG.