Accident Overview
On November 24, 2012, at approximately 0800 mountain standard time, a Piper PA-30, registration N8747Y, experienced a landing gear collapse during the landing roll at Deer Valley Airport (DVT) in Phoenix, Arizona. The airplane, owned and operated by Twin Comanche LLC, was conducting a local flight under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The airline transport pilot and two passengers were not injured.
Pilot Report
The pilot reported that he had not flown the airplane for nearly three months prior to the accident. He started the right engine using external power, disconnected the external power, then started the left engine using the airplane's electrical system, with the ammeter indicating a normal charge rate. Shortly after takeoff, a total electrical failure occurred. The pilot attempted to reset the alternators, voltage regulators, and battery switches but could not restore power.
He contacted Flight Service to relay his situation to the DVT air traffic control tower, requesting a light signal for clearance to land. While awaiting the signal, the pilot flew a wide circle to the north and west and performed the emergency landing gear extension procedure. He noted that the landing gear may not have retracted because the emergency extension lever was already vertical when inserted into the left socket. He pulled the release lever and pushed the lever forward per procedures but could not verify if the gear was locked electrically. The viewing mirror on the left engine nacelle indicated the nose gear appeared normal.
Landing and Subsequent Damage
The pilot reported a smooth touchdown on Runway 7L with the main landing gear. However, when the nose gear contacted the runway, all three landing gear retracted. The airplane slid off the right edge of the runway and came to rest in a rock-covered area, resulting in substantial damage to the undercarriage.
Postaccident Examination
An FAA airworthiness inspector examined the airplane and noted a clean-looking fracture at the landing gear motor attachment to the airframe, which appeared to be an overload failure likely resulting from the accident. The inspector suggested that the loss of electrical power might have been due to a master switch failure or intermittent operation. However, a follow-up examination by the NTSB IIC found the master switch functioned properly with no anomalies.
Maintenance Records
A review of the aircraft maintenance records showed that the most recent annual inspection was performed on July 16, 2012. During that inspection, the battery was checked according to the Piper Aircraft PA-30 Service Manual, and no anomalies were noted.
Emergency Gear Extension Procedures
The Piper Aircraft Corporation Report 1515, FAA Approved Flight Manual for the Piper Twin Comanche Model PA-30, provides instructions for emergency landing gear extension. These include reducing power and airspeed not exceeding 100 miles per hour, placing the landing gear selector switch in the "GEAR DOWN LOCKED" position, disengaging the motor, and using the emergency extension handle as specified. The manual notes that reducing power and rocking the handle can aid in manual extension and warns against retracting with the handle in the socket or re-engaging the motor in flight.
Probable Cause
The source does not state a probable cause for the accident.