Hughes 369D N138WH accident near Sulphur, Louisiana

Probable cause

The pilot's failure to maintain adequate separation between a long line being used to hoist linemen from a shield wire during an external load flight, which resulted in the long line being severed.

NTSB analysis

The commercial pilot was conducting an external load flight with two linemen hoisted beneath the helicopter on a long line. The pilot reported that, as he maintained a hover over the power lines, the long line contacted the shield wire as one of the linemen held onto a conductor bundle. The long line severed about midspan as the pilot turned the helicopter into the wind and attempted to move the linemen away from the conductor bundle. The two linemen were fatally injured when they fell about 100 ft to the ground. The pilot returned to the landing zone and landed uneventfully.

The pilot did not report any preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation. Video footage of the accident confirmed that the helicopter's synthetic long line severed after extended lateral contact with the braided steel shield wire.

Text from the NTSB. Open the NTSB docket for CEN18LA026 for the full record.