Narrative:

Initiated a VFR flight with FSS flight plan from ZZZ to ZZZ1 to return air ambulance personnel to home station. On long final for ZZZ1 the left main gear failed to indicate down on completion of gear extension cycle. The gear were cycled several times with no improving results. Gear were then lowered in emergency with no improving results. Center was then contacted informing them of the situation. Center declared an emergency. Center was then queried as to which airports were open with crf support. ZZZ2 was the nearest such airport. Flight diverted to ZZZ2 and I closed the VFR flight plan to ZZZ1. I declared an emergency with center. Flight proceeded to ZZZ2 VFR, direct, with gear up. Auxiliary tanks were emptied to keep remaining fuel away from cabin. I rehearsed the emergency landing and evacuate/evacuation with the ambulance crew. I also instructed crew to stow all equipment securely. Flight descended VFR to ZZZ2 for a low approach. During low approach/flyby, several crf members noted the left gear dangling/not locked. I concluded flight with final landing which occurred normally. I exited runway onto taxiway and deplaned the passenger. Aircraft was then moved, under its own power, with myself only to company X FBO. Examination this morning revealed a broken wire on the left main gear, which affects indication.

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Original NASA ASRS Text

Title: A CESSNA 421 DURING A GEAR EXTENSION PROB, DECLARED AN EMER AND DIVERTED. THE L MAIN GEAR POS INDICATION FAILED, CAUSED BY A BROKEN GEAR SENSOR WIRE.

Narrative: INITIATED A VFR FLT WITH FSS FLT PLAN FROM ZZZ TO ZZZ1 TO RETURN AIR AMBULANCE PERSONNEL TO HOME STATION. ON LONG FINAL FOR ZZZ1 THE L MAIN GEAR FAILED TO INDICATE DOWN ON COMPLETION OF GEAR EXTENSION CYCLE. THE GEAR WERE CYCLED SEVERAL TIMES WITH NO IMPROVING RESULTS. GEAR WERE THEN LOWERED IN EMER WITH NO IMPROVING RESULTS. CTR WAS THEN CONTACTED INFORMING THEM OF THE SIT. CTR DECLARED AN EMER. CTR WAS THEN QUERIED AS TO WHICH ARPTS WERE OPEN WITH CRF SUPPORT. ZZZ2 WAS THE NEAREST SUCH ARPT. FLT DIVERTED TO ZZZ2 AND I CLOSED THE VFR FLT PLAN TO ZZZ1. I DECLARED AN EMER WITH CTR. FLT PROCEEDED TO ZZZ2 VFR, DIRECT, WITH GEAR UP. AUX TANKS WERE EMPTIED TO KEEP REMAINING FUEL AWAY FROM CABIN. I REHEARSED THE EMER LNDG AND EVAC WITH THE AMBULANCE CREW. I ALSO INSTRUCTED CREW TO STOW ALL EQUIP SECURELY. FLT DSNDED VFR TO ZZZ2 FOR A LOW APCH. DURING LOW APCH/FLYBY, SEVERAL CRF MEMBERS NOTED THE L GEAR DANGLING/NOT LOCKED. I CONCLUDED FLT WITH FINAL LNDG WHICH OCCURRED NORMALLY. I EXITED RWY ONTO TXWY AND DEPLANED THE PAX. ACFT WAS THEN MOVED, UNDER ITS OWN PWR, WITH MYSELF ONLY TO COMPANY X FBO. EXAMINATION THIS MORNING REVEALED A BROKEN WIRE ON THE L MAIN GEAR, WHICH AFFECTS INDICATION.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.