HISTORY OF FLIGHTOn March 30, 2012, about 1708 Alaska daylight time, a ski-equipped Piper PA-18 airplane, N7276D, sustained substantial damage when it collided with trees and snow-covered terrain following a loss of control while landing, about 26 miles south of Sleetmute, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The uncertificated pilot, and the one passenger, both sustained fatal injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The accident flight originated at the Sleetmute Airport at an unknown time. During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on November 6, a witness and personal friend of the uncertificated pilot and passenger, reported that the airplane was being used to shuttle fuel and camping supplies to a remote cabin on the banks of the Holitna River. He said that before the airplane arrived, he and another friend used snow machines to pack-down a makeshift landing site on the frozen, snow-covered river. After the uncertificated pilot finished transporting all of the fuel and supplies, he and the passenger departed the site to check the condition of the river ice upstream. About 30 minutes later, the witness said he saw the airplane flying towards the makeshift site, flying "low and slow" over the treetops as it approached. He said that as the airplane flew towards the landing site threshold, it began a slight right turn, then it nosed down abruptly, and he heard the engine speed increase to a very high rpm setting. The airplane descend, nose down, in a near vertical attitude, and it began a 3/4 spiral turn downward, before descending from view into the trees at the approach end of the site. The airplane collided with the snow and tree-covered terrain in a near-vertical attitude. PERSONNEL INFORMATIONThe uncertificated pilot, age 42, did not have, nor had he ever had, a valid pilot certificate. His last student pilot/third class medical certificate was issued June 22, 1995, when he was 25 years old. A student pilot certificate, for an individual under 40 years old, is valid for 60 months. No records of the uncertificated pilot's flight history or experience were located. AIRCRAFT INFORMATIONThe accident airplane was equipped with a Lycoming O-320 engine, rated at 150 horsepower. No aircraft maintenance logs were located for the accident airplane. METEOROLOGICAL INFORMATIONThe closest weather reporting facility was the Sleetmute Airport, 26 miles north of the accident site. At 1716, a weather observation from the Sleetmute Airport was reporting, in part: Wind, 020 degrees (true) at 4 knots; visibility, 10 statute miles; clouds and sky condition, 9,000; temperature, 39 degrees F; dew point, 16 degrees F; altimeter, 29.30 inches Hg. AIRPORT INFORMATIONThe accident airplane was equipped with a Lycoming O-320 engine, rated at 150 horsepower. No aircraft maintenance logs were located for the accident airplane. WRECKAGE AND IMPACT INFORMATIONOn March 31, the NTSB IIC, two Alaska State Troopers, and an FAA operations inspector from the Anchorage Flight Standards District Office (FSDO), examined the airplane wreckage at the accident site. All of the airplane's major components were found at the main wreckage area. The airplane collided with snow and tree-covered terrain in a near-vertical, nose-down attitude, and remained in that position throughout the on scene investigation. The upper surface of the fuselage was oriented on about a 205 degree heading, and was canted to the right about 20 degrees. The right wing exhibited extensive spanwise leading edge aft crushing, and extensive aft chordwise wrinkling and folding. The aileron and flap remained attached to the wing, and the flap was retracted. The entire right wing was broken at the inboard wing attach points, and had spanwise downward displacement of the aft edge of the wing assembly. The left wing had spanwise leading edge aft crushing from the inboard end to about midspan, and had aft folding and crushing on about a 45 degree angle from midspan to the wingtip. The left aileron remained attached and had a upward bend at the outboard end. The left flap was extended about 30 degrees. Both lift struts remained attached to their respective wing and fuselage attach points. The empennage was undamaged. The elevator trim position appeared mid-range. The flight control surfaces remained connected to their respective attach points, and flight control system cable continuity was established to the cabin/cockpit area. The engine was entirely buried in soft snow-covered terrain on about a 45 degree nose-down attitude, almost to the firewall. One propeller blade was visible in the snow, and appeared to have a slight aft bend. There were no preaccident mechanical anomalies with the airplane. MEDICAL AND PATHOLOGICAL INFORMATIONA postmortem examination was conducted under the authority of the Alaska State Medical Examiner, Anchorage, Alaska, on April 2, 2012. The cause of death for the uncertificated pilot was attributed to blunt force, traumatic injuries, including an aortic laceration. The Federal Aviation Administration (FAA) Civil Aero Medical Institute (CAMI) conducted a toxicological examination on August 30, 2012. The examination revealed the presence of the following agents in the blood, brain, and vitreous: Ethanol detected in Brain (19 mg/dL, mg/hg) Ethanol detected in Blood (18 mg/dL, mg/hg) Ethanol detected in Vitreous (17 mg/dL, mg/hg) The NTSB's chief medical officer reviewed the pilot's autopsy and toxicological reports, remarking that the pilot was not likely to have been impaired at these low levels of Ethanol. TESTS AND RESEARCHGarmin GPS At the time of the accident, the uncertificated pilot was using a Garmin GPSMAP 276 portable global positioning system (GPS) receiver, capable of storing route-of-flight data. The unit was sent to the NTSB's Vehicle Recorders Division for examination. An NTSB electrical engineer was able to extract the GPS data for the accident flight, which included, in part, time, latitude, longitude, and GPS altitude. Groundspeed and course information were derived from the extracted parameters. The GPS data logs for March 30, 2012, revealed that at 1646 the airplane departed from a remote cabin on the banks of the Holitna River. After departure, the airplane turned south and followed the river while flying at a low altitude. The airplane then continued to fly southbound over the river for about 9 miles, and then it turned back to the north, while again following the river. As the airplane approached the cabin, it begins a series of turns near the cabin. As the airplane approached the site of the makeshift landing site, it began a gradual descent, and the GPS-derived groundspeed continued to decrease. The last GPS-derived groundspeed and direction of travel was 52 mph on a 253 degrees (True) course, at 1708. A flight track map overlay, and tabular data corresponding to the accident flight are available in the public docket for this accident.