Narrative:

While practicing stalls in clean and dirty configurations; I; as the pilot in command; observed that the gear safe light did not light when gear handle was placed in gear extension position. Gear extension cycle seemed otherwise normal. I checked the indicator bulb to verify that the bulb was not burned out. Gear was cycled four times without resolving the situation; instructor on board cross-checked my actions. Operating manual was referenced to very correct emergency extension procedures. Manual pump was actuated. Problem was not resolved. Based on the gear design; it was fairly certain that the main gear was down and locked. At issue was whether or not the front gear was down and locked. I then executed a low-level flyby of an airport with a tower. Their visual observation was that the gear appeared to be in the normal extended position. I then decided to make a precautionary landing at that airport instead of returning to my home base. The reason for this decision was that better emergency equipment was available and the clear area to either side of the runway was greater than at my home field. The shorter runway at selected airport was best aligned with the wind. Length was 3;800 ft. First approach involved idle power on front engine only to verify that rear engine power alone was sufficient to maintain a safe approach. After the successful completion of that step; I entered an approximate two mile final; shut down the front engine and feathered and leveled the prop. The purpose was to reduce the risk of damage to the prop or the front engine in the event of a nose gear collapse. Landing was made uneventfully. Gear held in the down position. Initial inspection of the aircraft by my regular mechanic showed that all three gear were in fact down and locked. Next step is to analyze gear down and locked electrical signal to determine if a switch has failed.

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Original NASA ASRS Text

Title: A C337's landing gear indicated unsafe with the gear down so the pilot declared an emergency; diverted to an airport with a wide runway; feathered the front propeller and landed safely with emergency equipment standing by.

Narrative: While practicing stalls in clean and dirty configurations; I; as the pilot in command; observed that the gear safe light did not light when gear handle was placed in gear extension position. Gear extension cycle seemed otherwise normal. I checked the indicator bulb to verify that the bulb was not burned out. Gear was cycled four times without resolving the situation; Instructor on board cross-checked my actions. Operating manual was referenced to very correct emergency extension procedures. Manual pump was actuated. Problem was not resolved. Based on the gear design; it was fairly certain that the main gear was down and locked. At issue was whether or not the front gear was down and locked. I then executed a low-level flyby of an airport with a Tower. Their visual observation was that the gear appeared to be in the normal extended position. I then decided to make a precautionary landing at that airport instead of returning to my home base. The reason for this decision was that better emergency equipment was available and the clear area to either side of the runway was greater than at my home field. The shorter runway at selected airport was best aligned with the wind. Length was 3;800 FT. First approach involved idle power on front engine only to verify that rear engine power alone was sufficient to maintain a safe approach. After the successful completion of that step; I entered an approximate two mile final; shut down the front engine and feathered and leveled the prop. The purpose was to reduce the risk of damage to the prop or the front engine in the event of a nose gear collapse. Landing was made uneventfully. Gear held in the down position. Initial inspection of the aircraft by my regular mechanic showed that all three gear were in fact down and locked. Next step is to analyze gear down and locked electrical signal to determine if a switch has failed.

Data retrieved from NASA's ASRS site as of April 2012 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.