Hughes 369D N555JC accident near Cherokee, Alabama

Probable cause

The pilot's spatial disorientation during a low-level river crossing in rainy, gray, reduced visibility meteorological conditions, which resulted in the helicopter's subsequent descent and impact with the water. Contributing to the accident was the pilot's decision to attempt the low-level crossing under those meteorological conditions.

NTSB analysis

The commercial pilot of the helicopter positioning flight delayed the takeoff for inclement weather to pass. However, about 1/2 hour after taking off, the helicopter encountered rain, fog, and low-visibility, gray-lighting conditions. The helicopter approached a 1-mile wide river, landed briefly onshore, then took off again and began a low-altitude crossing while paralleling a bridge. The helicopter was observed at an estimated 25 feet above the river before it began descending at a 10- to 15-degree angle into the water about mid-way through the crossing. It impacted the water nose-low, left side down, at a sufficient speed for the witness to see the tail "kick over" the main rotor blades and snap off. There were no onboard recording devices to confirm what occurred. No preexisting anomalies were found with the helicopter, and no medical issues were identified that would have affected the pilot's performance. The reason that the pilot landed before crossing the river could not be determined. Although the pilot's attention could have been momentarily diverted, it was more likely that the rainy, gray, reduced-visibility conditions resulted in low altitude spatial disorientation.

Text from the NTSB. Open the NTSB docket for ERA15FA178 for the full record.