Incident Overview
A helicopter landed in the Detroit River following an engine sputter and airframe vibration. The pilot reduced power and collective, then pushed the cyclic forward. Engine RPM decreased from 3000 to 2500, but rotor and engine RPM remained synchronized. The pilot adjusted descent with collective and forward speed with cyclic, pulling full collective just before impact.
Passenger Accounts
One passenger reported hearing a sputtering noise but stated the engine was running until impact. Another described the engine sound as a muffled misfiring. Both passengers noted that the pilot did not mention any problem, and the helicopter seemed under control until the moment of impact.
Post-Accident Examination
After recovery from the water, examination of the engine showed that the spark plugs were worn and contained a heavy buildup of carbon and lead. Near the operator's hangar, five sealed and one unsealed fuel drums were observed with standing water on their tops. No other evidence indicated any malfunction of the aircraft.