AN LC320 DECLARED AN EMER DUE TO NOSE LNDG GEAR FAILED TO EXTEND. CAUSED BY A FAILED HYD SWITCH BYPASSING THE EXTEND CYLINDER.

Narrative

WHILE LNDG FROM A LCL PROFICIENCY FLT; WAS UNABLE TO GET THE NOSEWHEEL LOCKED DOWN. MAINS BOTH LOCKED OK; BUT NO INDICATION OF THE NOSE DOWN AND LOCKED. A NUMBER OF ATTEMPTS TO EXTEND WITH ALTERNATE EXTENSION; PORPOISING THE ACFT; YAWING THE ACFT; AND PULLING SOME G'S WERE INEFFECTIVE. ANNOUNCED SITUATION ON ZZZ UNICOM (UNMONITORED AND NO TFC WAS IN THE LCL AREA). MADE A NORMAL APCH. SHUT OFF THE MIXTURE CTL ON SHORT FINAL AND HELD THE NOSE OFF AS LONG AS POSSIBLE. NOSE GEAR FOLDED (IF INDEED IT WAS EVER EXTENDED). THE PROP TIPS BENT AS THE ENG WAS STILL WINDMILLING; BUT NOT UNDER PWR. ENG DID NOT STOP SUDDENLY. ONLY DAMAGE TO AIRPLANE WAS TO THE PROP AND THE LOWER FIBERGLAS ENG COWLING. CAUSE UNKNOWN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE LNDG GEAR IS CTLED AND OPERATED HYDRAULICALLY AND THE FAILURE OF THE NOSE GEAR TO EXTEND WAS A HYD SWITCH WHICH FAILED; ALLOWING HYD FLUID TO BYPASS THE EXTEND CYLINDER. THE PROP TIPS WERE BENT AND THE LOWER ENG COWLING SUSTAINED SCRATCHES. THE ENG WAS SENT OFF TO THE MANUFACTURER AND FOUND OK WITH NO DAMAGE BUT DID FIND CORROSION ON THE CRANKSHAFT.