Piper PA30 N8747Y accident near Phoenix, Arizona

Probable cause

The pilot's failure to properly inhibit the landing gear transmission motor consistent with the emergency landing gear extension procedure, which precluded the full extension of the landing gear. Contributing to the accident was the airplane's electrical system anomaly, which rendered the gear position indicator inoperative.

NTSB analysis

The pilot reported that he had not flown the airplane in over 3 months. He started the right engine on external power, unplugged the external power, and then started the left engine off of the airplane's electrical system, with the ammeter showing a normal charge rate. Immediately after takeoff and while the landing gear was being retracted, the airplane experienced a total electrical failure; all attempts to restore electrical power were unsuccessful. The pilot then performed the emergency landing gear extension procedure, which he said included pulling the landing gear transmission motor release lever and pushing the lever full forward. The pilot subsequently placed the emergency gear extension handle in the left socket because it was in the vertical position, which should have indicated to the pilot that the landing gear had not completely retracted and that the landing gear transmission motor's force was not disengaged. He then most likely secured the handle and rotated it forward to complete the gear extension; however, due to the electrical failure, he had no way of confirming that the landing gear was locked down. After relaying his situation to the departure airport's air traffic control tower, the pilot was cleared to land. Upon landing, the airplane's nose gear slowly collapsed, and then both main landing gear collapsed. The airplane subsequently slid off of the right side of the runway and came to rest in a rock-covered area, which resulted in substantial damage to the airplane. Although the electrical system could have been compromised due to the electrical load required during the landing gear retraction because of insufficient battery power, it could not be determined if this caused the electrical system anomaly. During the emergency landing gear extension procedure, the forward rotation of the landing gear handle in the left socket likely prevented it from reaching its full-forward travel to lock the gear down because the pilot likely failed to fully disengage the landing gear transmission motor's forces from the system.

Text from the NTSB. Open the NTSB docket for WPR13LA060 for the full record.