NTSB Factual Report

HISTORY OF FLIGHT

On October 1, 2016, at 1310 eastern daylight time, a Culver PQ-14A, N4648V, collided with trees, terrain, and a commercial building during a forced landing after takeoff from the Hickory Regional Airport (HKY), Hickory, North Carolina. The commercial pilot was fatally injured, and the airplane was destroyed. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight.

Information from witnesses and HKY air traffic control tower controllers revealed that the airplane's engine stopped producing power during taxi for takeoff. The pilot explained to the controller that he "didn't know why it quit," but that he got the engine restarted. The airplane then departed from runway 24.

Shortly after takeoff, the pilot reported to the controller that he was "having engine problems" and announced his intention to return to HKY. The controller provided the altimeter setting, the wind information, and cleared the airplane to land on "any runway."

Radar data revealed that the airplane was about 2 miles south of HKY when it reversed course in the direction of runway 01. The radar track ended near the accident site, which was about on the extended centerline of runway 01 and about 1 mile south of the approach end of the runway.

Witnesses near the accident site described the engine sound as "sputtering" and "revving up and down." According to one witness, "I saw [the airplane] come over the hill, it was sputtering, and then it would rev back up. The airplane would climb a little when the engine ran, and then it would descend when it sputtered." The witness further stated that the airplane disappeared from view and the sounds of impact were heard.

PERSONNEL INFORMATION

The pilot held a commercial pilot certificate with ratings for airplane single-engine land, multi-engine land, and instrument airplane. His most recent Federal Aviation Administration (FAA) third-class medical certificate was issued on October 2, 2014. He reported 2,462 total hours of flight experience on that date.

A review of the pilot's logbook revealed that he had accumulated 2,478 total hours of flight experience at the time of the accident of which about 400 hours were in the accident airplane. He accrued 7.5 total hours of flight experience in the year before the accident of which 3.5 hours were in the accident airplane.

AIRCRAFT INFORMATION

According to FAA records, the airplane was manufactured in 1944. Examination of maintenance records revealed that the airplane's most recent annual inspection was completed on November 12, 2015, at 744.4 total aircraft hours.

Differences between the airplane's fuel system and the fuel system schematic depicted in the airplane's maintenance and operating manuals could not be reconciled.

According to the FAA Fuels Program Branch, a supplemental type certificate (STC) was required to use automobile gasoline in certificated aircraft and aircraft engines. An STC was available for the use of automobile gasoline in the Franklin 6A4-150-B3 engine that was installed in the airplane, but there was no STC for the Culver PQ-14A airplane.

A review of the accident airplane's records found no STC recorded for the use of automobile gasoline.

According to a line service technician employed by the fixed base operator (FBO) at HKY, he observed the pilot/owner servicing the accident airplane from 5-gallon cans. When asked if he had ever serviced the accident airplane with fuel, the technician stated he had never seen the airplane serviced at the FBO.

METEOROLOGICAL INFORMATION

At 1253, the weather reported at HKY included clear skies with 10 miles visibility. The wind was variable at 4 knots. The temperature was 23°C, the dewpoint was 11°C, and the altimeter setting was 30.09 inches of mercury.

According to the New Carburetor Icing-Probability chart published by the Australian Transport Safety Bureau, atmospheric conditions were conducive to "serious icing at descent power" and "moderate icing at cruise power."

Transport Canada has published TP 10737, "The Use of Automotive Gas (Mogas) in Aviation." Chapter 3.2 "Carburetor Icing," stated, "Mogas is generally higher in volatility than Avgas. Mogas will thus absorb more heat from the mixing air when vapourizing, resulting in ice accumulation at higher ambient temperatures. THE LIKELIHOOD OF CARB ICING WHILE FLYING ON MOGAS IS HIGHER."

According to National Transportation Safety Board Safety Alert 29, "Engines that run on automobile gas may be more susceptible to carburetor icing than engines that run on Avgas."

WRECKAGE AND IMPACT INFORMATION

The wreckage was examined at the accident site on October 2, 2016. There was a strong odor of automobile gasoline, and all major components were accounted for at the scene. The wreckage path was oriented 359° magnetic and was about 100 ft in length. The initial impact point was in a tree about 35 ft above ground level, and ground scars were visible in the pavement about 25 ft before where the airplane came to rest against a building.

The wreckage was divided into three main sections: the engine and instrument panel, the wings and cabin floor structure, and the empennage with a nearly intact tail section. All sections remained attached by cabling and wires. The preimpact position of the engine controls, including carburetor heat, could not be determined due to impact damage.

Each wing contained three interconnected tanks that comprised the "main" fuel system. An auxiliary tank was also installed. All six tanks leaked fuel due to impact damage to the tanks and their connections. Continuity of the fuel lines was established from the tanks to the fuel selector, in-line auxiliary fuel pump, and the engine through several breaks. The fuel selector was in the "Main" position, and no blockages were found. All fuel drained from the airplane presented the odor and appearance of automobile gasoline. Control continuity was established from the cockpit area to all flight control surfaces. Sheet metal and cabling associated with the empennage, the horizontal and vertical stabilizers, and the elevators were identified.

The propeller remained attached, and the blades were bent or fractured in an aft direction. The engine was separated from the wreckage, and impact damage was noted to the No. 5 cylinder and the crankcase. The engine was rotated by hand, and continuity was established through the powertrain and the valvetrain to the accessory section. Compression was confirmed using the thumb method. The engine could not be rotated through 360° due to a mechanical stop.

The crankcase cover was removed, and damage to the crankcase was found that impinged upon the No. 5 cylinder and blocked the piston skirt, which stopped rotation. The internal engine components moved smoothly, were well lubricated, and showed no abnormal wear.

The engine-driven fuel pump was removed, and it pumped fuel when actuated with a drill. The hand-driven auxiliary "wobble" pump was pumped fuel when actuated by hand. All fuel screens were absent of debris. The carburetor was disassembled, and the internal parts moved freely and were undamaged. The metal floats were intact. The carburetor bowl was absent of debris.

The left magneto was removed, and, when actuated with a drill, it produced spark at all terminal leads. The right magneto was impact damaged, and the distributor was destroyed. The magneto drive was actuated with a drill, and spark was produced at the secondary output of the ignition coil.

MEDICAL AND PATHOLOGICAL INFORMATION

The Office of the Chief Medical Examiner, Raleigh, North Carolina, did not perform an autopsy on the pilot but completed an external examination. The probable cause of death was "multiple blunt force trauma."

The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on the pilot. Toxicological samples tested were negative for ethanol. Salicylate (aspirin) was detected in urine.

NTSB Probable Cause

The loss of engine power due to carburetor icing. Contributing to the accident was the pilot's use of automobile gasoline, which increased the likelihood of carburetor icing.