Virginia Beach, VA, USA
N685SE
FREEMAN HERITAGE COLLECTION SE5A
The pilot was performing the first flight after assembly of the experimental airplane. The day before, the pilot started and taxied the airplane with no anomalies observed, and the preflight taxi and engine run-up on the morning of the accident flight also revealed no anomalies. The pilot advanced engine power slowly for takeoff and the engine ran "perfectly" as the airplane quickly accelerated and became airborne. When the airplane was about 200 to 300 feet above ground level and more than 3/4 of the way down the runway, he sensed that the engine was losing power. By the end of the runway, it became apparent that it was losing power. The pilot then started a gradual left turn and attempted to troubleshoot the loss of power but realized that the airplane was not going to make it back to the airport. The pilot performed a forced landing to a recently harvested cornfield, during which the airplane sustained substantial damage. Examination of the airplane’s vintage engine did not reveal evidence of any preimpact malfunction or failure that would have precluded normal operation. The engine was not equipped with carburetor heat and review of a carburetor icing probability chart revealed that the atmospheric conditions at the time of the accident were conducive to the formation of carburetor ice. It is possible that while operating the airplane on the ground before takeoff (a period during which the engine would typically be operating at low power), carburetor ice started forming and continued until the engine began losing engine power during the initial climb. The fuel system was also of a vintage design and used an air pump to apply pressure to the fuel tank, enabling fuel to flow to the carburetor. According to the builder, a partial loss of power could have occurred if the fuel system was not properly vented, and the engine could have incurred fuel starvation as a result. Either carburetor icing or inadequate fuel venting could have resulted in a partial loss of power; however, it could not be determined which scenario occurred and resulted in the accident. Given the potential for either scenario, and that no evidence that a mechanical failure contributed to the loss of engine power, it is likely that an interruption of the normal fuel/air mixture to the engine resulted in the loss of engine power.
On October 3, 2017, about 0830 eastern daylight time, a Freeman Heritage Collection SE5A airplane; N685SE, was substantially damaged when it was involved in an accident near Virginia Beach, Virginia. The airline transport pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 test flight. The accident airplane had been assembled by the Fighter Factory, a division of the Military Aviation Museum, from parts obtained from the Freeman Heritage Collection and was owned and operated by Training Services Incorporated in the experimental exhibition category. According to the museum's chief pilot, the day before the accident, he started, taxied, and fast taxied (with the tail up) the airplane to ensure that it was operating properly for its first flight after being assembled. The intent was to fly it that day, but the wind speed and direction became unfavorable, and he decided to fly it early the next morning while there was little or no wind. All the checks that were done on the ground that day were completed satisfactorily, and he was comfortable that the airplane was ready for flight. On the morning of the accident, the wind was calm. The pilot started the airplane and taxied out to runway 29. The airplane started and ran well during taxi and run-up. He advanced the power slowly and the engine ran "perfectly" as the airplane quickly accelerated and became airborne. Once in the air, he normally checked all gauges to assess how the airplane was running so that he could abort the takeoff and land on the remaining runway. The airplane "was running like a top" and had immediately accelerated to 80 mph, so the pilot committed to continuing the takeoff. About 200 to 300 feet above ground level, and more than 3/4 of the way down the runway, he sensed that the engine was losing power, even though he could hear no change in sound of the engine. As the airplane passed the departure end of the runway, it had become apparent that the engine was losing power. The pilot started a gradual left turn back to the airport but noted that the airspeed was decaying and that he would not make it back to the airport. The pilot selected a recently harvested cornfield as a forced landing site and continued to troubleshoot the engine. After committing to the landing, the pilot reduced the throttle to idle and the engine rpm decreased, which indicated to him that it was still running, but not producing enough power to sustain flight. As the airplane settled onto the 10- to 12-inch-high cornstalks, there was a loud "crack," a sudden drop, and a very hard vertical stop. The airplane's forward motion then suddenly stopped, and the airplane nosed over and came to rest. The airplane was substantially damaged. The main landing gear was broken in several places and shifted to the left of the airplane’s longitudinal axis. The upper wings were twisted and impact damaged, the right front interplane strut was broken, the leading edge of the center section, vertical stabilizer, and rudder were damaged, and one of the propeller blades had broken off from the hub. The engine was a vintage, water-cooled, normally aspirated, carburetor equipped, 8-cylinder, Vee configuration, reciprocating aircraft engine. Unlike most contemporary reciprocating aircraft engines, the engine was not equipped with carburetor heat or a fuel pump. Instead of a fuel pump, the valve gear housing was provided with an air pressure pump, the piston of which was operated by one of the cams. This pump was used to maintain air pressure on the gasoline in the fuel tank as part of a fuel “pressure system” which was designed to maintain fuel pressure at the carburetor at no more than 2 pounds per square inch. A relief valve was included in the system, which could be adjusted to correct for differences in altitude. Before engine start, the fuel tank needed to be pressurized. This initial pressure was obtained by a hand-operated air pump, which had an associated gauge on the instrument panel that indicated system pressure. The engine had accrued about 6 total hours of operation since major overhaul, and no anomalies were found with the engine during postaccident examination. The engine rotated by hand without binding, there appeared to be no mechanical failures, and the fuel system, lubrication system, and ignition system were found to be functional. According to the builder, he believed that the partial loss of power may have occurred due to improper venting of the fuel system, which may have resulted in fuel starvation. During the postaccident rebuilding process, the fuel system was changed from a pressurized system to a fuel pump-type system and included a vent to preclude another occurrence. Review of the weather conditions showed that at 0856, the weather reported at Fentress Naval Auxiliary Field (NFE), Fentress, Virginia, located 5 nautical miles west of the accident site, included a temperature of 20°C and a dew point of 14°C. The calculated relative humidity at this temperature and dewpoint was 69%. Review of the carburetor icing probability chart contained within Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were conducive to the formation of serious icing at glide [idle] engine power settings.
A partial loss of engine power due to an interruption of the normal fuel/air mixture to the engine.
Source: NTSB Aviation Accident Database
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