Delta, AK, USA
N92770
PIPER PA-12
Witnesses reported that the airplane was departing a private airstrip. It reached an altitude of about 200-300 feet above the ground when the engine lost all power, and the airplane began a left turn. During the turn, the airplane's nose pitched down abruptly, and the airplane collided with the ground in a steep, nose-down attitude. Two of the witnesses, both of whom are pilots, noted that before the loss of power, the engine made some popping noises and sounded unusual. A postaccident examination of the airframe and engine disclosed no mechanical malfunctions. A carburetor icing probability chart indicated that the relative humidity and temperature at a nearby airport about the time of the accident was conducive to serious icing at glide power. Although carburetor icing was possible, absent any mechanical malfunctions or fuel contamination, it could not be determined why the engine lost power. The accident site was adjacent to a road and about 300 yards from a clear field. Despite these potential landing areas, the pilot decided to attempt to return to the airstrip by initiating a turn at low altitude and low airspeed following the loss of engine power, which resulted in an aerodynamic stall and a loss of control with insufficient altitude to recover. During the impact, the pilot's seat separated from the airframe and moved forward about 6 inches, which allowed the pilot to impact the instrument panel and subsequently contributed to the severity of the pilot's injuries.
HISTORY OF FLIGHT On July 17, 2011, about 1500 Alaska daylight time, a Piper PA-12 airplane, N92770, received substantial damage when it collided with tree-covered terrain following a loss of engine power after takeoff from a private airstrip near Delta Junction, Alaska. The sole occupant, a commercial pilot, was fatally injured. The flight was operated as a visual flight rules (VFR) personal flight under the provisions of Title 14 Code of Federal Regulations Part 91 when the accident occurred. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was en route to the Fairbanks International Airport, Fairbanks, Alaska. Friends of the pilot stated that he was in town to attend a wedding function. He flew in the day before the accident and remained overnight. The next morning, multiple acquaintances were with the pilot at the airstrip, and observed the accident. Two witnesses observing the takeoff, both commercial pilots, reported that as the airplane flew overhead, they heard some "light popping," and the engine sounded quieter than normal. Approximately 200 to 300 feet above the ground, the engine went quiet. The pilot made a left turn, which was followed by a nose and left wing low descent. The airplane collided with terrain about 250 yards from the departure end of the airstrip. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for airplane single and multiengine land, rotorcraft, instrument airplane, and instrument helicopter. He was also a helicopter pilot for the United States Army. His most recent third-class medical certificate was issued on June 11, 2010, and contained no limitations. No personal flight records were discovered for examination, and the pilot’s flight experience was obtained from his June 11, 2010, application for an FAA medical certificate. On the application he indicated a total pilot time of 230 hours, with zero hours in the last six months. AIRCRAFT INFORMATION The accident airplane was equipped with a Lycoming O-320 engine, rated at 150 horsepower. The engine was installed on April 17, 1991, and had a service time of 2,636.5 hours at the time of the accident, and 636.5 service hours since its last major overhaul on August 15, 2001. The engine was equipped with a two-blade McCauley propeller. At the time of the accident, the airframe had 4,351 service hours. The last annual inspection was performed on February 2, 2011, at 4,325.5 service hours. METEOROLOGICAL INFORMATION The nearest official weather observation station is Allen Army Airfield (PABI), Delta Junction, which is 4 nautical miles southwest of the accident site. At 1453, an Aviation Routine Weather Report (METAR) was reporting, in part: Wind, 080 degrees (true) at 3 knots; visibility, 10 statute miles; clouds and sky condition, few 4,000 feet, scattered at 6,000 feet; temperature, 65 degrees; dew point, 47 degrees; altimeter, 29.74 inches. WRECKAGE AND IMPACT INFORMATION On July 18, two NTSB investigators and two inspectors from the FAA’s Fairbanks Flight Standards District Office examined the airplane at the accident site. The airplane impacted level, wooded terrain adjacent to a private airstrip. It came to rest upright, in a nose-low attitude, and was resting on several toppled and broken trees. The tail was suspended against a tree by the right vertical stabilizer. All control surfaces were identified at the accident site, and flight control continuity was verified to all flight control surfaces. Both wings had spanwise leading edge crushing. A portion of the right wing was separated and remained in a tree adjacent to the wreckage. The wing flaps were extended. About 10 gallons of fuel was drained from the right wing fuel tank. No fuel was found in the left wing fuel tank; however, it was noted that the fuel gascolator valve was opened as a result of impact damage, and fuel was observed on the ground below the gascolator valve. No fuel was in the gascolator bowl, and the screen was free of contamination. The left and right wing fuel tank selectors were in the “ON” position. There was fuel in the carburetor float bowl, and no water was detected in the fuel. The propeller separated from the engine at the crankshaft propeller flange. One propeller blade was bent slightly aft, and the opposite blade was undamaged. The engine remained attached to the airframe, and was relatively free of damage, except the bent crankshaft flange, and some bending of the exhaust piping. The throttle and mixture control were in the full-forward position. The master switch was placed in the off position by first responders to the accident site. The carburetor heat was in the off position. The pilot’s seat frame is bolted to the fuselage by four tabs, and is not adjustable. The lap portion of the seat belt system is connected to the seat frame. The fixed shoulder harness was connected to a cross bar at the top of the fuselage. The pilot’s seat frame broke at or near 3 of the 4 connection points during the accident, and the seat shifted forward approximately 6 inches. All of the fracture surfaces on the seat frame fractures were consistent with overload. The empennage was mostly free of impact damage. The right elevator was resting against a tree and the trailing edge was crushed and bent upward. Both main landing gear were bent upward and aft from their connecting points and exhibited signs of right-side loading. MEDICAL AND PATHOLOGICAL INFORMATION After the accident, the pilot received on-site medical attention from first responders, and was taken to a local clinic for treatment. He was initially alert and responsive to questions, but had no recollection of the accident sequence. He rapidly deteriorated in the medical clinic, requiring life support, and died enroute by air to Anchorage, the location of the nearest Trauma Center. A postmortem examination of the pilot was done under the authority of the Alaska State Medical Examiner, Anchorage, Alaska, on July 18, 2011. The examination revealed that the cause of death for the pilot was attributed to multiple blunt force injuries. The FAA's Civil Aerospace Medical Institute, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy. Results were negative for carbon monoxide, cyanide, and ethanol. Etomidate was detected in the blood and urine, 0.048 ug/ml of Midazolam was detected in the urine, and Propofol was detected in the urine. Midazolam, Etomidate, and Propofol were used for sedation by the medical treatment providers. TESTS AND RESEARCH The airplane was recovered to the facilities of Alaska Claims Services, Inc., Wasilla, Alaska. On August 12, the NTSB Investigator-in-charge (IIC) examined the airframe in a hangar at the Alaska Claims facility. During the examination, no preaccident airframe anomalies were noted. The fuel supply system was examined for anomalies as well. No obstructions of the fuel supply system were noted from either fuel tank to the engine compartment, and no obstruction of the fuel vent system was noted. On August 18, an engine examination was performed by Alaska Aircraft Engines, Anchorage, under the supervision of the NTSB IIC. The teardown included inspection of all engine accessories and external components, and the separation of the two crankcase halves in order to remove and inspect all the internal engine components. No anomalies, contamination, or evidence of malfunction were found in any of the engine accessories, to include the magnetos, ignition harness, induction system, sparkplugs, oil pump, oil cooler, and oil filter. The cylinders, pistons, valve train, crankshaft, and other internal components were all without evidence of anomaly or malfunction. ADDITIONAL INFORMATION According to a carburetor icing probability chart, the conditions at the time of the accident were conducive to serious carburetor icing at glide power settings. From where the airplane was parked the morning of the accident, the pilot would have taxied approximately .25 miles to the approach end of the airstrip. The accident site is bordered on the east side by a north-south running dirt road that was approximately 20 feet wide, with additional clear space on each side of the road that varied in width. Approximately 300 yards north of the accident site is a large open field.
The pilot's decision to make a low-altitude turn back to the airport following a loss of engine power, which resulted in an aerodynamic stall and loss of control. Contributing to the severity of the pilot's injuries was the separation of the pilot's seat during impact.
Source: NTSB Aviation Accident Database
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