Robinson R66 N4QW accident near Pikeville, North Carolina

Probable cause

The pilot’s failure to see and avoid a small diameter wire during low altitude agricultural spraying operations. Contributing to the accident was the pilot’s insufficient property survey.

NTSB analysis

The pilot was applying insecticide to a farm field and the accident flight was the first time the pilot had sprayed the field. Once he arrived at the site, 3 hours late, the pilot conducted two circular passes to survey the field, then landed, and the ground crew loaded the insecticide into the hopper. The pilot was not briefed of any hazards to operations prior to the flight by the ground crew or farmer. After takeoff, the pilot started applying the chemicals.

The helicopter was performing the spraying operation and was flying on a northerly heading when it impacted a non-energized wire. The wire was mounted about 30 feet up a 40 ft pole that also contained a hunting stand and stretched about 250 ft across the field from west to east where it connected to a tree bordering the field. The wire had been installed at least 20 years earlier and was installed high enough that a tractor or combine had clearance to move beneath it during harvest.

Clear daylight conditions existed at the time of the accident. The sun was at 39.85° above the horizon at an azimuth of 272.39° and was very close to being directly in line with the wire. It is possible that the sun’s position relative to the wire would have made the 5/16-inch wire more difficult to see as the shadow of the wire and pole would have been nearly directly under the wire rather than offset.

The pilot, unfamiliar with the field, running late, and without the benefit of a detailed discussion with the landowner, relied solely on his brief visual surveillance of the field while operating the helicopter. Although the pilot likely observed the pole and hunting stand during his surveillance, it is likely that he did not see the wire due to its small diameter. Therefore, shortly after initiating the application of the insecticide, the pilot’s failure to see and avoid the wire resulted in the helicopter impacting the wire and the pilot’s subsequent loss of control and impact with terrain.

Text from the NTSB. Open the NTSB docket for ERA20LA220 for the full record.