WPR12LA097 · Beech 58P

The pilot of the twin-engine airplane was on a sightseeing diversion while en route to an airport when two "ALT" annunciator lights on the instrument panel illuminated, and the load meters indicated that the alternators were not providing electrical power to the airplane. The pilot powered off some electrical equipment and recycled both alternator switches. The "ALT" annunciator lights extinguished, and all other indications returned to normal. Since nightfall was approaching and the pilot was concerned about the continued availability of electrical power, he then headed for his destination. When the airplane was on short final, the pilot noticed that none of the three green landing gear position annunciator lights were illuminated despite the fact that he had selected the landing gear down. He reported this information to the air traffic control tower controller, conducted a go-around, and asked for the controller's observations regarding the landing gear position. The pilot misunderstood the air traffic controller's communication that the landing gear was not extended. Subsequently, the pilot did not recycle the gear and did not review or execute any abnormal checklist procedures for the landing gear. Although the landing gear warning horn sounded during the second landing approach, the pilot incorrectly believed that the landing gear was extended and landed the airplane with the landing gear fully retracted. Although the landing was accomplished 31 minutes before local sunset and 58 minutes before the end of local civil twilight, the pilot did not go around again due to his concern about approaching nightfall.

While the airplane was in temporary storage awaiting postaccident examination, the owner of the repair facility, who had previously repaired the landing gear system and had conducted the most recent annual inspection on the airplane, gained unapproved access to the airplane, operated the landing gear, and inadvertently damaged the airplane. Subsequent examination of the airplane by investigators revealed that the landing gear system operated normally, and no irregularities were revealed with the electrical system.

According to the airplane manufacturer, without alternator augmentation, the airplane battery would have lasted about the same amount of time that it took for the flight to depart and reach the location where the pilot first noticed the electrical anomaly. Based on this information and the fact that the airplane had been tampered with, no detailed component testing was accomplished, and the root causes of the initial electrical anomaly and failure of the landing gear to extend could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset