ERA18LA215 · Cessna R182

Before departure on the personal flight, the private pilot reported that the engine had to be started using an auxiliary power supply because the battery was dead; however, he did not determine the reason for the dead battery. After the engine was started, he reported normal electrical system indications. About 10 minutes into the 20-minute flight, the pilot noticed that the electric fuel gauges were reading zero and the ammeter was showing a discharge. He did not consult or comply with emergency procedures from the pilot's operating handbook (POH) for a discharging ammeter and continued to his destination, where he attempted to extend the landing gear using the normal system; however, there was no down-and-locked indication. He confirmed visually that the nose landing gear was down and locked; he performed a fly-by of the air traffic control tower, was informed that the landing gear appeared to be down, and returned for landing. After touchdown, both main landing gear collapsed, the airplane began to veer to the left, and the left wing and horizontal stabilizer contacted the runway. The airplane came to rest in the grass off the left side of the runway. Postaccident examination and operational testing of the normal and emergency landing gear extension and indicating systems revealed no evidence of preimpact failure or malfunction that would have precluded normal operation. Had the pilot shed unnecessary electrical load per the POH when he first noticed the discharging state or pumped the landing gear down using the emergency gear extension mechanism, it is likely that the landing gear would have extended and locked into position. The reason for the electrical system failure was not investigated.

Verbatim NTSB analysis and probable cause from the NTSB dataset