What happened
A Massachusetts State Police helicopter departed a helioport carrying two crewmembers and two passengers. After climbing to approximately 600 feet over a river, witnesses observed a puff of smoke or vapor emitting from the engine exhaust. The aircraft then turned toward the river bank and began a steep descent at an angle between 45 and 70 degrees. Observers noted that the main rotor blades were either slowing down or had already stopped before the helicopter struck the roof of a boathouse.
The investigation
Investigators found no evidence of any preimpact failure regarding the transmission or the main rotor. However, an examination of the engine revealed that five of the six fuel injection ports were clogged. Analysis of samples taken from the helicopter's fuel system showed the presence of water and iron oxide.
Further investigation into the source of the fuel identified a 6,000-gallon in-ground storage tank owned by the MSP that had not been maintained or secured for 14 years, with the exception of a single filter change occurring between 1984 and 1986. Samples taken from this storage tank contained high levels of water and rust, along with degraded thermal properties.
Findings
The investigation identified a significant lack of oversight within MSP air operations, noting the absence of any formal training, safety, or fuel management programs. Flight records indicated that over the preceding five years, the pilot had received only one training session, which consisted of a two-day ground school and a single formal training flight.