Aviation Accident Summaries

Aviation Accident Summary CEN11LA083

Nocagdoches, TX, USA

Aircraft #1

N36405

PIPER PA-34-200T

Analysis

While in cruise flight, about 1 hour and 10 minutes after departure, the left engine lost power. The pilot proceeded to the nearest airport and as he maneuvered the airplane onto the base leg of the traffic pattern, the right engine lost power. He performed a wheels-up forced landing about 600 feet from the runway. He said he had departed with full fuel. A postaccident examination by Federal Aviation Administration inspectors found no evidence of fuel leakage, and the only visible fuel was approximately 5 gallons of unusable fuel. However, retrieval crews reported a very strong smell of avgas when they arrived one hour after the accident. They estimated at least ten to fifteen gallons of avgas was in both the left and right wing tanks. No anomalies were found with the airplane.

Factual Information

On November 28, 2010, at 1123 central standard time, a Piper PA-34-200T, N35405, registered to and operated by the pilot, was substantially damaged when the pilot made a wheels up forced landing after both engines lost power near Nocagdoches, Texas. Visual meteorological conditions (VMC) prevailed at the time of the accident. The personal flight was being conducted under the provisions of 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot, the sole occupant on board, received minor injuries. The cross-country flight originated at Sugar Land (SGR), Texas, approximately 1100, and was en route to Shreveport (SHV), Louisiana. According to the pilot's accident report, he was in cruise flight at 2,900 feet msl (above mean sea level) at 160 KIAS (knots indicated airspeed) and consuming 14 gph (gallons per hour) each engine. The airplane had been aloft for 1 hour, 10 minutes when the left engine RPM and manifold pressure "dropped significantly." The pilot proceeded to the nearest airport, Nocagdoches (OCH) and entered the traffic pattern. As he turned onto the base leg for runway 18, the right engine lost power. The pilot made a wheels up forced landing at the intersection of FM225 and CR711, about 600 feet prior to the runway. Both wings, the horizontal stabilizer and stabilator were bent. The airplane had recently underwent unknown repairs to the mixture cables, and had recently had a new interior installed. Two Federal Aviation Administration (FAA) inspectors from the Houston Flight Standards District Office went to the accident site and examined the airplane. In a memo as to their findings, the inspectors said they believed the pilot took off with only 49 gallons of fuel on board. They consulted the airplane's performance charts and estimated that the flight would have consumed approximately 49 gallons of fuel. They figured that the pilot fueled each wing the evening before the accident, but before it could drain from the wet tank to the bladder tank, the fuel overflowed through the filler neck leaving the pilot to think the tanks were full. The inspectors said they could find no evidence of fuel leakage at the accident site. The only visible fuel was approximately 5 gallons of unusable fuel (as stated in the Pilot's Operating Handbook) in the fuel tanks. An airframe and powerplant mechanic sent to recover the airplane reported in a written letter that he arrived on site approximately one hour after the accident. "There was a very strong smell of avgas," he wrote. "It appeared that all six fuel tanks had been compromised from the impact with trees during the forced landing." Six hours later, "The pungent odor of spelled avgas was still quite strong." He said that when the airplane was recovered the next morning, "there was so much avgas in the compromised fuel tanks that extra measures would be needed...to drain the avgas." He concluded that "there was plenty of fuel in both the left and right fuel tanks. I would estimate that there was at least ten to fifteen gallons of avgas in the right wing and about the same in the left wing. There was some mechanical anomaly that caused both engines {to lose power]." According to the Pilot's Operating Handbook and the PA-34-200T Service Manual, each wing has interconnected aluminum inboard and outboard (wet) fuel tanks (with a bladder tank in the middle), having a combined capacity of 64 gallons, for a total capacity of 128 gallons. A large tube, approximately 3 inches in diameter, connects the tanks, allowing fuel from the outboard tank to flow into the inboard tank as the fuel from the inboard tank is being consumed.

Probable Cause and Findings

A total loss of power in both engines for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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