Piper PA-32R-301T N8197W accident near Chandler, Arizona

Probable cause

The failure of the alternator and/or battery, which prevented the operation of the landing gear extension system and resulted in the nose landing gear collapsing during the landing roll.

NTSB analysis

The pilot reported that, about 1 hour 10 minutes into the flight, the airplane began experiencing alternator and battery problems. The radios were inoperative because there was no electrical power, so he diverted from an airport with an air traffic control tower to an airport without one. He selected the landing gear lever to extend the gear normally. He also operated the emergency landing gear extension system. During the landing roll, the nose landing gear (NLG) collapsed, the airplane departed the runway, and the right wing leading edge and aileron sustained substantial damage.

During a postaccident examination of the airplane, a check of the alternator found no field and no output voltage. The battery was charged to 12 volts, and it subsequently discharged to 10 volts with no load over 1 hour. The airplane was equipped with a retractable tricycle landing gear, which was hydraulically operated by an electrically powered reversible pump; the loss of electrical power prevented the hydraulic pump from actuating, which prevented the landing gear from extending normally. However, operation of the emergency extension system allowed the landing gear to free-fall, and two springs were provided to assist the NLG to the down position. During postaccident testing with battery power, the landing gear operated normally during both normal operation and emergency extension; the failure of the NLG to lock could not be duplicated.

The landing gear positions were indicated by three green lights located above the selector lever for the gear down-and-locked position. However, these lights would not have been operable due to the total electrical failure, and, therefore, the pilot had no means to verify that all three landing gear were not down and locked before touchdown.

Text from the NTSB. Open the NTSB docket for WPR13LA237 for the full record.