Aviation Accident Summaries

Aviation Accident Summary WPR13LA237

Chandler, AZ, USA

Aircraft #1

N8197W

PIPER PA-32R-301T

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.

Factual Information

HISTORY OF FLIGHTOn May 19, 2013, about 1245 mountain standard time, a Piper PA32R-301T, N8197W, had the nose landing gear collapse during landing at Stellar Airpark, Chandler, Arizona. The pilot/owner was operating the airplane under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The private pilot and three passengers were not injured; the airplane sustained substantial damage to an aileron. The cross-country personal flight departed Brown, Field, San Diego, California, with a planned destination of Williams Gateway Airport, Mesa, Arizona. Visual meteorological (VMC) conditions prevailed, and no flight plan had been filed. The pilot reported that he observed the airplane's gauges while en route, and all systems appeared to be functioning normally. The amp meter showed the alternator appeared to be charging. About 1 hour 10 minutes into the flight, he noticed that the amp meter was at zero. A few minutes later, he heard static in the radios; he shut off all electrical systems to preserve battery power. About 40 miles from Williams Gateway Airport, he turned on his radio to contact the air traffic control tower, but all electrical power was depleted, and he could not establish contact. He elected to divert to Stellar Airpark, which did not have a control tower. The pilot made a straight in approach to runway 35, lowered the landing gear normally, and operated the emergency landing gear extension system. The airplane touched down on the main landing gear without incident; as the nose came down, he noted that the propeller made ground contact. He raised the nose as long as possible, but with the nose gear collapsed, he could not control the airplane once the nose contacted the ground. The airplane departed the runway surface into the grass; the right wing leading edge and aileron sustained substantial damage. ADDITIONAL INFORMATIONPostaccident Examination A Federal Aviation Administration (FAA) inspector oversaw a postaccident examination of the airplane. The landing gear operated normally, in normal operations and emergency extension. Maintenance personnel could not duplicate a failure of the nose landing gear to extend down and lock. A check of the alternator found no field and no output voltage. The battery was then charged to 12 volts, and found to discharge to 10 volts with no load over 1 hour. Landing Gear System The PA-32R-301/301T is equipped with a retractable tricycle landing gear, which is hydraulically operated by an electrically powered reversible pump. A selector handle on the instrument panel to the left of the control quadrant is used to select gear up or down positions. Each landing gear is retracted and extended by a single hydraulic cylinder attached to the drag link assembly of the nose gear, and the side brace link assemblies of each main gear. Each main gear is held in its up position by hydraulic pressure within each cylinder. There are no uplocks in the system, and loss of hydraulic pressure will allow the gears to drop. When the pilot initiates emergency extension by operating a push-pull cable knob between the two pilot's seats, this allows the landing gear to free-fall. The nose gear has two springs (one inside the other) to assist the nose gear to the down position. The landing gear positions are indicated by three green lights located above the selector lever for the gear down and locked position. These lights will not operate with a total electrical failure.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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