ANC16FA001

The solo pilot departed from a gravel-covered airstrip. Witnesses reported that they saw the airplane make a left, 270-degree turn and eventually overfly the departure end of the airstrip. The airplane then climbed to about 300 ft above ground level, flew in a southeasterly direction over a nearby house, then began a climbing left turn. Witnesses said that the airplane pitched up, the left wing dropped, and the airplane descended vertically, nose first, disappearing behind a stand of tall trees. The airplane subsequently collided with a paved, rural roadway. A postcrash fire incinerated a large portion of the airplane's cockpit, left wing, and fuselage. A postaccident examination of the airframe and engine revealed no mechanical malfunctions or anomalies that would have precluded normal operation. Given the lack of mechanical deficiencies with the airplane and engine, the witness statements, and the nature of the damage to the airplane, it is likely that the pilot inadvertently exceeded the airplane's critical angle-of-attack while maneuvering at a low altitude, which resulted in an aerodynamic stall and a loss of control.

The Cessna 150F is a two-seat, high-wing, tricycle landing gear-equipped airplane. A Continental Motors O-200 engine, rated at 100 horsepower, powered it. At the time of the accident, the airplane was equipped with a Sensenich, fixed-pitch propeller. However, the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) review of the accident airplane's maintenance logbooks revealed that, on May 12, 2015, a McCauley fixed-pitch propeller had been installed, and there was no logbook entry for the installation Sensenich fixed-pitch propeller. According to family members and friends of the pilot, a different propeller had been temporally installed on the airplane while the pilot was waiting for a new propeller to arrive. The new propeller was scheduled to be installed the day after the accident. According to maintenance records, the last inspection performed on the airplane was an annual inspection dated May 4, 2015. At that time, the airframe had accumulated 3,806.55 total flight hours. The engine had accrued 1,434.2 flight hours since overhaul. On October 8, 2015, about 1340 Alaska daylight time, a Cessna 150F airplane, N7064, sustained substantial damage following an in-flight loss of control and subsequent collision with a rural road, shortly after departing from the Cubdivision Airport, Big Lake, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal flight under Title 14 CFR Part 91 when the accident occurred. The commercial pilot, the sole occupant, sustained fatal injuries. Visual meteorological conditions were reported in the area of the accident; no flight plan had been filed. The flight was originating at the time of the accident and was en route to the Big Lake Airport, which is about 3 miles south of the Cubdivision Airport. According to witnesses, the pilot had departed from the Big Lake Airport on the morning of the accident, arriving at the Cubdivision Airport, a 1,200-long by 100-foot-wide private gravel-covered airstrip, about 1230. About 1340, witnesses watched as the accident airplane departed to the north on runway 04. The witnesses reported that just after takeoff, the airplane made a left climbing 270-degree turn, and it eventually flew crosswind over the departure end of the runway. When the airplane reached about 300 feet above ground level (agl), the climb shallowed slightly as it passed over a workshop and a house located on the airstrip. As the airplane flew in a southeasterly direction, and away from the airport, witnesses reported that the airplane began another climbing left turn. During the turn, the airplane rolled to the left, then it descended vertically, nose first, and it subsequently descended behind a stand of tall trees and out of sight of the witnesses. The airplane subsequently collided with a paved, rural roadway. A postcrash fire incinerated a large portion of the airplane's cockpit, left wing, and fuselage. A postmortem examination was conducted underthe authority of the Alaska State Medical Examiner, Anchorage, Alaska, on October 9, 2015. The cause of death for the pilot was attributed to blunt force, traumatic injuries. The Federal Aviation Administration (FAA) Civil Aeromedical Institute performed toxicology examinations for the pilot on November 20, 2015, which was negative for carbon monoxide, drugs, and ethanol. The closest weather reporting facility was Wasilla, about 9 miles east of the accident site. At 1336, an aviation routine weather report (METAR) was reporting, in part: Wind 060 degrees at 13 knots with gusts to 19 knots; visibility, 10 statute miles; clouds and sky condition, overcast at 12,000 feet; temperature, 55 degrees F; dew point, 34 degrees F; altimeter, 29.30 in Hg. Pilots flying in the area around the time of the accident reported low-level wind gusts near the accident. The pilot, age 23, held a commercial pilot certificate with an airplane single and multi-engine land rating. His most recent second-class airman medical certificate was issued on February 26, 2015, with the limitation that he must wear corrective lenses. According to his logbook, the pilot had about 933 total flight hours. The pilot was flying a Cessna 172 professionally; the accident flight was his second flight in his personally owned Cessna 150 after returning home from a two-week duty rotation in Bethel, Alaska. On October 8, 2015, the NTSB IIC, along with various Alaska State Troopers, and a Federal Aviation Administration (FAA) aviation safety inspector from the Anchorage Flight Standards District Office (FSDO), Anchorage, examined the wreckage at the accident site. The main wreckage was located on a road, at 209 feet mean sea level (msl), at latitude N 61 35.1850 and longitude W 149 48.5249. The airplane impacted the road in a near vertical, nose-down attitude; a post-crash fire consumed the cabin, inboard portion of the left wing, and most the fuselage. All the major components of the airframe and engine were accounted for at the scene. On October 14, 2015, under the supervision of the NTSB IIC, the wreckage was examined at a private hangar in Wasilla, Alaska. Flight control system cable continuity was established from each control surface to the point of impact and fire-related damage. The forward wing spar remained intact; both wing struts remained attached at their respective attachment fittings. The outboard portion of the left wing showed torsional twisting from the root to the wingtip, and the wing root was thermally damaged. The right wing displayed aft crushing of the leading edge. Control continuity to the left and right ailerons and elevators was established from the yoke to the control surface. The flap selector was thermally damaged. The flap actuator on the right wing was measured at 0.15 inches, corresponding to a flap retracted position. The aft portion of the left and right seat rails were attached to the airframe and undamaged, the forward portion of the seat rails werethermally damaged. The nose gear assembly and main gear struts of the fixed tricycle landing gear remained intact and attached. The fuel selector valve was in the on position. The outer portion of the left horizontal stabilizer was deformed upward, and it was attached at the forward and aft attachment points. The outer portion of the left elevator was impinged on the left horizontal stabilizer due to impact damage. The right horizontal stabilizer and elevator were attached at their respective attachment points and undamaged. Rudder continuity was established from the rudder pedals to the rudder. The rudder was undamaged, the balance weights for the elevator and rudder were attached. The Sensenich propeller remained attached to the crankshaft's propeller flange, which separated from the engine. Both blades exhibited torsional twisting toward low pitch, heavy leading edge gouging and deep chord-wise scrapes. The outboard four inches of one of the blades was torn free from the propeller and was not observed. On November 12, under the supervision of the NTSB IIC, an engine teardown and inspection were conducted at a private hangar in Wasilla, Alaska. The engine sustained significant thermal and impact-related damage. The carburetor and No. 4 cylinder was fractured and separated from the engine. Teardown of the engine revealed no signs of operational distress or pre-accident anomalies with the internal components. The mixture and throttle control cables remained attached to their respective control levers, and the throttle valve was in the closed position. The carburetor inlet fuel screen was not obstructed. The floats sustained thermal damage and one was separated from the float clip. The spark plugs showed signs of normal wear. The left magneto remained attached to the backside of the engine and the right magneto was separated. The right magneto produced spark in each of the distributor towers when the drive shaft was manually rotated. The left magneto sustained significant thermal damage. The left magneto was removed from the engine and the impulse coupling snapped when the drive shaft was manually rotated, but it did not produce a spark on the distributor towers. Internal examination revealed thermal damage to the cam follower and cracking of the distributor block. The cam follower was slightly adjusted to compensate for the thermal deformation and the drive shaft was again rotated. Spark was observed at one of the distributor block towers and at the points during each snap of the impulse coupling. Rotational scoring was observed on the interior of the vacuum pump housing. The NTSB's postaccident examination of the airframe and engine revealed no mechanical malfunctions or anomalies that would have precluded normal operation.