On October 21, 2003, a Hughes 369HS (registration N49TJ) was involved in an aviation accident near Evansville, MN. Investigators recorded the probable cause as: The pilot's misjudgment of clearance from the surface of the lake during the aerial application pass. The low altitude operation, glassy water, and his visual perception were contributing factors. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter was substantially damaged after striking a lake during an aerial application flight. The pilot reported losing depth perception due to glassy water conditions, leading to the skids contacting the water.
Accident Details
A helicopter was substantially damaged during an in-flight collision with a lake while conducting an aerial application pass. The local flight was operating from a temporary load site near the lake shoreline.
Pilot Statement
The pilot reported that conditions at the time included calm winds and sunrise with the sun coming up over trees to the east, creating a glassy water condition. During the spray run, the pilot stated that he must have lost depth perception with the water surface, allowing the helicopter's skids to contact the water. The aircraft decelerated rapidly, and water came up over the bubble as the aircraft pitched forward. The pilot also noted that he should have looked at the trees along the shoreline for a vertical reference instead of at the water, because with glassy water it is hard to judge distance.
Aircraft and Operations
The pilot reported no malfunctions with the aircraft or engine prior to the accident. The helicopter was operating as an aerial application flight from a temporary load site near the lake.