Summary
On August 30, 2013, about 2024 Alaska daylight time, a tundra tire-equipped Piper PA-18A (Super Cub) airplane, N4581A, was destroyed by impact and a postimpact fire after colliding with tree-covered terrain just after takeoff from the Tatitna Airport, about 51 miles southeast of Nikolai, Alaska. The private pilot was fatally injured and the sole passenger sustained serious injuries. The airplane was operated under 14 Code of Federal Regulations Part 91 as a visual flight rules personal cross-country flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight departed Tatitna Airport about 2020, destined for Big Lake Airport, Big Lake, Alaska.
Flight History
According to family members, the flight was returning to Big Lake, the pilot's home airport, after a successful caribou hunt. On the day of the accident, the pilot had completed multiple trips shuttling passengers, caribou meat, and hunting gear from a remote hunting location to Tatitna Airport. The passenger stated that after refueling the main wing fuel tanks and loading two butchered caribou and other gear, they taxied to the end of the runway and departed to the east. Once above the treetops, they initiated a left turn when the pilot started to swear and said, "I should have taken off the other way." The passenger then shut his eyes and put his hands up, with no recollection of the accident sequence. A witness on the west end of the airport reported good visibility but said it was "a little windy." He observed the airplane takeoff from the 1,200-foot-long gravel runway, begin a shallow climb, followed by a gradual left turn before descending into the trees just beyond the departure end. Another witness, who arrived at the airport around 1700, observed the accident airplane depart multiple times to the east with a tailwind. At the time of the accident, he was inside a cabin near the airport when he heard gunfire; he walked out and noted the wind was still out of the east, and the airplane had departed with a tailwind.
Personnel Information
The pilot, age 58, held a private pilot certificate with an airplane single-engine land rating. His most recent third-class medical certificate was issued on May 10, 2011, with the limitation that he must wear corrective lenses. No personal flight records were located; FAA records indicated his total aeronautical experience was about 2,000 hours, with 60 hours in the previous 6 months.
Aircraft Information
The airplane was a 1956 model year Piper PA-18A Super Cub, equipped with a Lycoming O-320-A2B engine rated at 150 horsepower at 2700 RPM. No airframe or engine logbooks were discovered.
Meteorological Information
The closest weather reporting facility was Farewell Lake Seaplane Base, about 22 miles northwest. At 1853, a METAR reported wind calm, visibility 15 statute miles, overcast ceiling at 4,000 feet, temperature 57°F, dew point 46°F, and altimeter 30.02 inches. FAA weather cameras at Rohn, near the west end of Tatitna Airport, recorded images to the northwest, east, and south. At 20:27:06, about 3 minutes after the accident, the east camera captured smoke traveling in an easterly direction.
Airport and Wreckage
The Tatitna Airport has a 1,200-foot-long gravel runway. The accident site was approximately ½-mile northeast of the airport at an elevation of about 1,450 feet mean sea level. The airplane impacted in a near vertical attitude in sparsely populated spruce trees. The nose was on approximately a 205-degree heading. The initial impact point was marked by a cut treetop atop a 40-foot-tall spruce tree; the distance to the main wreckage was about 72 feet. Cut branches with flat angular fractures and black paint transfer marks were found from the initial impact to the wreckage. All major components were at the main site. Both wing fuel tanks were ruptured and partially consumed by fire. The inboard portions of both wings, the cockpit, and cabin area were incinerated. Flight control continuity was verified from all primary surfaces to the cockpit. The engine sustained fire and impact damage; both propeller blades remained attached, with one exhibiting leading edge gouges, torsional twisting, and chordwise scratching, and the other showing aft bending about eight inches from the tip. Examination revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Weight and Balance
Due to extensive fire damage, an exact weight and balance calculation could not be made. Using estimates from available data, the NTSB IIC conservatively estimated the airplane's gross weight at the time of the accident at 2,392.25 pounds, which is 642.25 pounds over the approved maximum takeoff gross weight of 1,750 pounds. The estimated center of gravity was positive 25.07 inches, outside the allowable range of positive 14.0 to 20.0 inches at maximum gross weight. The load included the pilot (250 pounds), rear seat passenger (200 pounds), caribou meat (500 pounds), caribou antlers (15 pounds), a rifle (8 pounds), fuel (36 gallons, 216 pounds), and oil (8 quarts, 15 pounds). The antlers were found between the left wing lift struts, and a rifle was attached to the right wing lift struts. No record of a multiple airworthiness certificate authorizing external load operations was found for the accident airplane.
Medical and Pathological
A postmortem examination conducted on September 3, 2013, attributed the pilot's cause of death to severe thermal injury. Toxicology tests performed on September 26, 2013, were negative for alcohol and drugs.