Aviation Accident Summaries

Aviation Accident Summary WPR09FA038

Sedona, AZ, USA

Aircraft #1

N3929W

PIPER PA-32-260

Analysis

The flight was the return leg of a personal sightseeing trip that had originated the day of the accident. Witnesses observed the airplane depart from the airport, and then fly below the ridge lines of an adjacent mesa in a pattern that was consistent with a sightseeing flight. The airplane then climbed above the mountain ridges and out of view. The wreckage was located about 1,600 feet above the airport elevation, in an area close to the last position observed by witnesses. Shortly after the accident the pilot stated to a witness, who was the first to arrive at the accident site, that the engine lost power. The pilot succumbed to his injuries 2 months following the accident, and as such could not be interviewed. The airplane was serviced with fuel prior to the flight, and traces of fuel were observed at the accident site. Propeller witness marks indicated that the engine had been rotating at the time of impact with terrain. The airplane was extensively damaged by postaccident fire; however, examination of the remaining wreckage revealed no obvious anomalies which would have precluded normal operation.

Factual Information

HISTORY OF FLIGHT On November 13, 2008, about 1645 mountain standard time, a Piper PA-32-260, N3929W, collided with wooded terrain above a mesa near Sedona, Arizona. The pilot/owner was operating the airplane under the provisions of Title 14 Code of Federal Regulations Part 91. The certificated private pilot sustained serious injuries, and the two passengers were killed. The airplane was destroyed by post accident fire. The cross-country personal flight departed the Sedona Airport (SEZ) about 1630, with a planned destination of Hangar Haciendas Airport (AZ90), Laveen, Arizona. Visual meteorological conditions prevailed, and no flight plan had been filed. According to relatives of the pilot and passengers, the flight had departed from the Phoenix area earlier in the day. They reported that the purpose of the trip was to conduct personal sightseeing flights in the Sedona area, with the accident flight being the return leg to Phoenix. A witness who was located close at a viewing area adjacent to Sedona airport reported observing a light colored, single-engine airplane depart from the northbound runway approximately 1630. He observed the airplane fly at a level attitude, and begin a, "slow" right turn to the east. The airplane continued and then began a turn to the south just below the tops of the cliff faces, which overlooked the airport. The airplane continued on the southbound heading and then began a 180-degree turn to the north. The airplane continued north and then passed beyond the end of the cliffs, and turned eastward and out of his view. A short time later he observed smoke on the plateau in the vicinity of the last observed location. A second witness, who stated that he was a pilot, reported similar observations. He stated that the airplane was of the low-wing type, and that it was flying at a low speed and altitude such that he thought it was sightseeing. He did not observe any smoke trailing from the airplane. A witness, located in the vicinity of the accident site, submitted a written statement. He reported observing a small single-engine airplane flying to the east, away from Sedona at about 1645. Five minutes later he observed smoke rising from a distant wooded area. He immediately proceeded towards the smoke, and arrived at the accident site 20 minutes later. While at the site, he administered first aid to the pilot, who was outside of the burning airplane. The pilot relayed to the witness that the engine "sputtered" a single time and then, "shut down." He further reported to the witness that he unsuccessfully attempted to restart the engine, and subsequently made a forced landing. The pilot stated that prior to the crash one of the passengers had "passed out." Operators in the vicinity of the airport reported not hearing any mayday or distress calls on the Sedona UNICOM (the common traffic advisory frequency for the airport). The pilot succumbed to his injuries 2 months following the accident. Due to the nature of the injuries, the NTSB investigator-in-charge was unable to interview the pilot. PERSONNEL INFORMATION A review of Federal Aviation Administration airman records revealed that the pilot, age 51, was issued a private pilot certificate on May 24, 2005, with a rating for airplane single-engine land. The pilot was issued a third-class medical certificate in October 2008, with limitations that he wear lenses for distant vision and that he possess glasses for near vision. An examination of the pilot's flight logbook revealed that the last flight time entry was on October 18, 2008, and at that time he reported a total of 379 hours of total flight experience. An entry by a Certified Flight Instructor, dated March 8, 2008, stated that the pilot was proficient in the operation and systems of a high performance airplane. AIRCRAFT INFORMATION The low-wing, fixed-gear airplane, was manufactured in 1967. It was powered by a six-cylinder, Textron Lycoming O-540 engine, and equipped with a Hartzell two blade, constant-speed propeller. Maintenance records indicated that an annual inspection was completed on February 1, 2008, at a recorded tachometer time of 3,341.3 hours. At the time of the annual inspection, the engine had accumulated 1,484.8 flight hours since manufacture in June 1982. Fueling records from the Sedona Airport Administration established that, prior to the accident flight, the airplane was serviced with the addition of 13.5 gallons of 100-octane low lead aviation fuel. METEOROLOGICAL INFORMATION The closest official weather observation station was Ernest Flagstaff Pulliam Airport, Flagstaff, Arizona, located about 18 miles north of the accident site. The elevation of the weather observation station was 7,015 feet mean sea level (msl). An aviation routine weather report was issued at 1656, and it stated: wind variable between 270 and 340 degrees at 9 knots, gusting to 19 knots; visibility 10 statute miles; skies clear; temperature 16 degrees Celsius; dew point minus 5 degrees Celsius; altimeter 30.10 inches of mercury. The approximate density altitude at the weather reporting station was 8,500 feet. The manager of an aircraft tour operator located at Sedona airport reported that the winds at the time of the accident were calm, with temperatures of about 24 degrees Celsius with unrestricted visibility. AIRPORT INFORMATION Sedona Airport is located on a 500-foot-high mesa that overlooks the town of Sedona. The terrain descends steeply from the airport on all sides to the valleys below. Terrain to the north and east is characterized by mesa formations that rise to about 6,500 feet within a distance of 6 miles. The Airport/Facility Directory, Southwest U. S., indicated runway 03 was 5,132 feet long and 100 feet wide with an airport elevation of 4,830 feet. WRECKAGE AND IMPACT INFORMATION The accident site was located at the 6,400-foot level, 6 miles northeast of Sedona Airport, on a plateau overlooking the Sedona Valley area. The site was characterized by 10 degrees downsloping rocky terrain, lightly dispersed with oak, juniper, and pine trees. The first identified point of contact (FIPC) was located about 40 feet above ground level on a tree trunk. A section of the left wing fuel tank was located at the base of the tree. The section of wing exhibited a 30-inch diameter indentation that corresponded to the diameter of the tree trunk. The debris field continued on a heading of 340 degrees magnetic to the location of the outboard section of the left wing, 190 feet from the FIPC. The main wreckage came to rest 60 feet beyond the left wing. The main wreckage came to rest inverted on a heading of 240 degrees magnetic. It consisted of the fuselage, right wing, left wing inboard of the aileron, vertical stabilizer and rudder, horizontal stabilator, engine, and propeller. The engine aligned with the cabin and had become separated from the firewall. The right wing was inverted and folded back at the wing root such that it was parallel with the main cabin. Fire consumed the entire fuselage structure, the center section of stabilator, and the right wing trailing edge, flaps, and aileron. The right main fuel tank sustained impact and thermal damage and was breached along the aft lower rivet line. Traces of blue colored liquid were observed in the tank. All major sections of airplane were accounted for at the site. MEDICAL AND PATHOLOGICAL INFORMATION Review of the pilot's medical certificate application revealed that he had indicated the use of Lisinopril and Synthroid. Additionally, he stated that his right knee was fused. Autopsies for the passengers were conducted by the Coconino County Medical Examiner. The cause of death for both occupants was reported as the effects of thermal injuries. A report of external examination for the pilot was issued by the Maricopa County Office of the Medical Examiner. The cause of death was reported as complications of thermal injuries. TESTS AND RESEARCH Airframe All control cables were secure to the appropriate controls and continuous to their respective surfaces except the left aileron control cable, which was separated in a broomstraw manner just inboard of the bellcrank. The stabilator trim wheel shaft extension was measured, and according to the Piper representative correlated to an approximately 50 percent nose up trim position. The flap torque tube was in a position that corresponded to the flaps being fully retracted. The fire damaged fuel selector valve was in the left tip tank position. Engine Removal of the engine spark plugs revealed the top spark plug electrodes from cylinders two, four, and six to be oil-soaked. The remaining spark plug electrodes were light gray in color, which corresponded to normal operation according to the Champion Aviation Check-A-Plug AV-27 Chart. The spark plugs appeared worn beyond normal service limits when compared to the Champion Aviation chart. An inspection of the cylinders was performed via the utilization of a lighted borescope; the valves were intact, combustion chambers remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The mechanical fuel pump had become separated at the diaphragm housing and displaced from the wreckage; the pump flange was securely attached to the accessory case. The diaphragm was exposed and had sustained thermal damage. The spark plug harnesses were destroyed by fire. Both magnetos were securely attached to their mounting pads. The right magneto was partially consumed by fire. The left magneto sustained thermal damage and heavy sooting. Both magnetos were removed; thermal damage prevented rotation by hand. The flywheel was fractured and had become separated at the hub; due to its separation, ignition timing could not be confirmed. The carburetor separated from the intake flange, was detached from its control cables, and came to rest underneath the engine. The carburetor was visually inspected, and it was noted that all parting surface bolts and locking tabs were in place. The carburetor was then disassembled. The parting surface gasket, floats, and rubber needle valve sustained thermal damage and had disintegrated. The fuel intake screen was removed, and found free of blockage. The engine crankshaft was manually rotated utilizing the hub. The crankshaft rotated, and the valves moved approximately the same amount of lift. Valve train continuity was confirmed through to the accessory case, and thumb compression was obtained on all six cylinders. Removal of cylinder number one revealed the internal cylinder dome and piston crown to exhibit light brown combustion deposits. The piston rings were intact and residual oil was observed in the crankcase. The camshaft lobes of cylinder one and six were inspected, and found clean and free of scour marks and abrasions. The oil sump screen was observed heat distressed, and free of blockage. The oil filter exhibited external impact damage and remained attached to the filter mount. The oil sump drains were in place and securely affixed to the sump. Propeller The propeller separated from the crankshaft at the propeller flange. Both blades exhibited chordwise abrasions, S-bending, and leading edge gouges. The tips of both blades separated approximately 3 inches from the tip in a jagged S-pattern.

Probable Cause and Findings

The partial loss of engine power while maneuvering for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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