History of Flight
On August 24, 2010, about 1945 Alaska daylight time, a Piper PA-11, registration N78831, sustained substantial damage when it impacted terrain approximately 25 miles southwest of Willow, Alaska. The flight was operated by the private pilot under 14 CFR Part 91. Visual meteorological conditions prevailed, and a visual flight rules flight plan was filed. The pilot and passenger were killed. The cross-country flight departed Lake Hood Strip Airport, Anchorage, at about 1915, with an intended destination of Rainy Pass Lodge Airport.
Two witnesses on a hunting trip, located about one mile southeast of the accident site near the Susitna River, heard an airplane approaching. One witness, familiar with small airplanes, reported the airplane was flying over the river at less than 100 feet. As they watched it pass, the engine seemed to be running smoothly. About one to two minutes later, they heard a "strange noise" like something had "flapped the water." Earlier that day, they had observed a small moose near the accident site.
A digital video recorded by one witness showed the airplane flying straight and level at low altitude over the Susitna River, with no irregular engine sounds.
Another witness, flying from Skwentna to Anchorage, reported seeing dark smoke rising above a tree line around 1945. He flew toward the smoke and saw an object engulfed in flames on a sandbar. After several passes, he recognized it as aircraft wreckage and notified the FAA Kenai Flight Service Station.
Friends and family reported that the pilot intended to scout for wildlife during the flight. No witnesses to the accident sequence were identified.
Personnel Information
The pilot, age 28, held a private pilot certificate with airplane single-engine land and sea ratings. A second-class FAA medical certificate was issued on July 9, 2010, with no limitations. The pilot reported 230 total flight hours on his most recent medical application. Personal logbooks were not located.
Aircraft Information
The two-seat, high-wing, fixed-gear Piper PA-11, serial number 11-1605, was manufactured in 1947. It was powered by a Teledyne Continental Motors C-90 engine, rated at 95 horsepower, with a Sensenich M76AK-4 fixed-pitch propeller. Maintenance records indicated an annual inspection on December 14, 2009, at a tachometer reading of 473.5 hours, airframe total time 3,755.5 hours, engine total time 3,098.5 hours, and engine time since major overhaul 1,298.5 hours. The tachometer was damaged at the site, preventing current readings.
Meteorological Information
Recorded data from Ted Stevens Anchorage International Airport, about 30 miles southeast of the accident site, at 1953 reported wind from 240 degrees at 5 knots, visibility 10 statute miles, few clouds at 5,000 feet, scattered clouds at 7,500 feet, temperature 17°C, dew point 8°C, and altimeter setting 29.98 inHg.
Wreckage and Impact Information
The accident site was on the northwestern edge of a sandbar along the Susitna River. The airplane came to rest in a near-vertical attitude on a heading of about 291 degrees magnetic, at approximately 53 feet MSL. No ground impressions or debris path were observed within about 300 feet. Recent moose hoof prints were noted about 200 feet south of the main wreckage.
The fabric covering of both wings, fuselage, and empennage was consumed by fire. All major structural components remained attached to the fuselage. The engine was partially embedded in soft terrain and remained partly attached. Examination of the airframe and flight control system revealed no evidence of preimpact mechanical malfunction. The wreckage was moved for further examination.
Medical and Pathological Information
The Alaska State Medical Examiner conducted an autopsy on the pilot on August 25, 2010, determining the cause of death as multiple blunt force injuries. FAA's Civil Aeromedical Institute performed toxicology tests, which were positive for acetone, ethanol (from sources other than ingestion), and methanol in various tissues.
Survival Aspects
The Rescue Coordination Center received reports of Emergency Locator Transmitter (ELT) 121.5 MHz signals from military aircraft in the area around 1945. The accident airplane was equipped with a 121.5 MHz ELT. As of February 1, 2009, satellite monitoring of 121.5 MHz ELTs (SARSAT) was terminated. The NTSB had issued Safety Recommendation A-07-51 urging the FAA to mandate 406 MHz ELTs, but as of March 2011, the FAA had not done so, and the recommendation was classified as "Open-Unacceptable."
Tests and Research
The recovered engine was examined on September 23, 2010. All four cylinders remained attached to the crankcase. Both magnetos had thermal and fire damage and would not rotate. The propeller blades showed twisting and bending opposite the direction of normal rotation, with leading edge polishing and gouges on one tip. No mechanical anomalies were found that would have precluded normal operation.