Bell Helicopter Textron 206L-1 N114AE accident near Manchester, Kentucky

Probable cause

The pilot’s loss of helicopter control due to spatial disorientation when he inadvertently encountered night, instrument meteorological conditions, which resulted in the in-flight separation of the main rotor and tailboom.

NTSB analysis

The air ambulance repositioning flight was en route to base following a patient transfer. Weather information forecast about 3 hours before the accident indicated a moist environment; however, visual conditions were anticipated around the time of the accident. An updated forecast was published about 10 minutes before the accident, and it indicated that fog or low stratus cloud development was possible and that visibility could decrease to near or below airport weather minimums in the early morning hours. Witness statements and the reported weather conditions indicated that patchy fog had developed near the helipad at the time of the accident and that visibility at the accident site was 1/4 mile; however, the specific visibility conditions encountered by the helicopter during its approach could not be determined. A witness reported seeing the helicopter "flying lower than normal" and then spinning before impact. Another witness reported seeing the helicopter in a nose-down attitude and then impact the ground.

The wreckage was located in a school parking lot, which was about 750 feet from the landing pad and at an elevation of about 900 feet mean sea level (msl). The wreckage distribution was consistent with an in-flight separation of the main rotor and tailboom. An examination of the helicopter airframe, engine, and related systems revealed no preimpact anomalies that would have precluded normal operation. Both the main rotor assembly and tailboom separated in overload.

Review of GPS data showed the accident helicopter descending in three right circuits near the landing pad just before the accident. The final recorded data were in the immediate vicinity of the accident location and indicated an altitude of 1,437 feet msl. The maneuvering flightpath of the helicopter before the accident was consistent with an attempt to avoid fog followed by a loss of control. Although the pilot was instrument rated, he had not logged recent instrument time. Further, although the pilot had recent training in night vision goggle usage and had night vision goggles available during the flight, it could not be determined if he was using them at the time of the accident. Given the reports of fog in the area and the accident circumstances, it is likely that the pilot entered instrument meteorological conditions during the approach to the helipad, which resulted in spatial disorientation and loss of control.

Text from the NTSB. Open the NTSB docket for ERA13FA273 for the full record.