What was found
NOSE GEAR COLLAPSED ON LANDING. COULD NOT GET A NOSE GEAR SAFE LIGHT AFTER PERFORMING EXTENSIVE EMERGENCY GEAR LOWERING PROCEDURES. EXTENSIVE DAMAGE TO GEAR DOORS, NOSE, PROPS, AND TO ENGINES REQUIRING TEAR DOWN AND OVERHAUL. CAUSE WAS THE BOLT HEAD SEPARATION P/N 400-004 (AN4-7A) ON ONE BOLT WHICH ALLOWED THE NOSE GEAR STEERING CHANNEL TO PIVOT OUT OF POSITION PREVENTING THE NOSE GEAR TO EXTEND COMPLETELY.