What happened
On 17 September 2006, an amateur-built VariViggen aircraft, registration N106VV, departed Bangor Airport, Maine, for a planned flight to Goose Bay, Labrador. The flight was conducted under visual flight rules. After a stop in Bangor to refuel, the aircraft continued its journey toward Canada. During the flight, the aircraft's GPS data and recovered digital photographs indicated that the flight was proceeding normally through clear weather. However, two minutes before the aircraft struck the trees near Plaster Rock, New Brunswick, the aircraft began an uninterrupted descent at a rate of approximately 800 feet per minute. The impact, which occurred at a low altitude of roughly 1,600 feet above the ground, resulted in the destruction of the aircraft and one fatality.
The investigation
The investigation focused on the cause of the engine failure and the delay in the search and rescue response. Examination of the wreckage revealed that the aircraft's wings had separated upon impact and the fuselage had landed inverted. While the engine showed no mechanical defects, investigators discovered significant water contamination in the fuel system. Approximately one ounce of fluid, consisting of 90 percent water, was found in the gascolator, and additional water was present in the engine-driven fuel pump.
Analysis of the fuel system showed that while the main and ferry tanks were likely free of contamination, the wing tanks were not. Because the fuel transfer switch was found in the ON position, investigators concluded that water had been transferred from the wing tanks into the main tank, where it eventually reached the engine. Furthermore, the investigation noted that the pilot had not activated his VFR flight plan upon departure from Bangor, which prevented air traffic controllers and search and rescue authorities from knowing the aircraft was overdue until several days later.
Findings
- The wing tanks became contaminated with water, though the exact source of the moisture could not be determined.
- The engine stopped because water transferred from the wing tanks to the main tank and was subsequently delivered to the engine.
- The aircraft lacked dedicated fuel tank drains, which prevented the pilot from performing a thorough pre-flight inspection of the wing tanks for contaminants.
- The low altitude of the flight limited the pilot's ability to manage the engine failure and select a suitable landing site.
- The delay in the search and rescue operation was caused by the pilot's failure to activate the filed flight plan.