A C402 ON LNDG ROLLOUT AT LOW SPD THE ACFT EXPERIENCED A RWY EXCURSION AND LOSS OF CTL CAUSED BY A FAILED L MAIN LNDG GEAR TORQUE LINK APEX BOLT.

Narrative

ON APR/XZ/98 I WAS LNDG RWY 12 AT VGT. AFTER LNDG; THE L MAIN GEAR STARTED TO WOBBLE. I HAD THE ACFT SLOWED TO 7- 10 KTS JUST ABOUT TO EXIT WHEN THE L MAIN TWISTED SIDEWAYS DUE TO A BOLT BREAKAGE; AND THE ACFT VEERED OFF THE RWY AND SETTLED IN THE DIRT. I HAD THE ENGS SHUT DOWN RIGHT BEFORE WE LEFT THE RWY. THE FAA FOUND THE MISSING BOLT DOWN THE RWY. FACTORS INCLUDED A STRONG XWIND. I THINK THE PROB WITH THE BOLT WAS DUE TO MANY DIFFERENT PLTS FLYING THE SAME ACFT DAY IN AND DAY OUT ON GRAND CANYON TOURS; WHICH IN TURN MIGHT HAVE WEAKENED THE BOLT DAYS BEFORE. I THINK I MADE PROPER JUDGEMENT LNDG ON A XWIND RWY THAT TWR ASSIGNED SINCE I'VE LOGGED SEVERAL THOUSAND LNDGS BEFORE WITHOUT ANY INCIDENT. THE WINDS WHEN I LANDED WERE 220 DEGS AT 15 KTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT ON LNDG ROLLOUT THE ACFT STARTED TO WOBBLE AND THE RPTR SLOWED THE ACFT AND SHUT DOWN THE ENGS. THE RPTR SAID THE CAUSE OF THE L MAIN GEAR FAILURE WAS THE TORQUE LINK'S APEX BOLT FRACTURE ALLOWING THE STRUT PISTON TO TURN 90 DEGS. THE RPTR STATED THE FAA RECOVERED THE BOLT SEGMENTS FROM THE RWY.