KANEOHE, HI, USA
N64F
Bell 204-B
The helicopter pilot was preparing to sling a metal utility pole. As he picked up the load, one of the sling lines snagged. Although ground personnel saw what was happening, the line slipped off before they were able to radio the pilot. The pilot had not verified the security of the load. When this occurred, a shock was transmitted through the airframe to the main rotor system. The pilot felt a resonance and put the load back on the ground. The resonance increased, however, and the pilot jettisoned the sling. The pilot reported that the control response had become mushy, and he believed he was losing control of the helicopter, so he initiated a precautionary landing. The helicopter was over sloping terrain, and as it touched down, the stinger and tail rotor struck the ground.
On June 6, 1997, at 1045 hours Hawaiian standard time, a Bell 204-B helicopter, N64F, made a hard landing near Kaneohe, Oahu, Hawaii. The aircraft sustained substantial damage; however, the pilot, the sole occupant, was not injured. The aircraft was being operated as an external load flight by Pacific Helicopter Tours, Inc., under 14 CFR Part 133 when the accident occurred. The flight originated in Honolulu, Hawaii, at 0730 that morning. Visual meteorological conditions prevailed and a company VFR flight plan was filed. According to the pilot, the aircraft was at a 50-foot hover as ground riggers were connecting slings to a 40-foot section of a metal utility pole. As he picked up the load, one of the sling lines snagged on the pole end cap. Although the riggers saw what was happening, the line slipped off the end cap before they were able to radio the pilot to put the load back on the ground. The pilot had not verified the security of the load. When the line slipped, a shock was transmitted through the airframe as a 1-to-1 vertical vibration to the main rotor system. The pilot felt the resonance and put the pole back on the ground; however, as the load settled the resonance increased. The pilot jettisoned the sling but the controls were becoming mushy. At this point he felt he was losing aircraft control and so he initiated a precautionary landing. The aircraft was over a 15-degree upslope when the aircraft touched down and the stinger and tailrotor struck the ground. The tail rotor driveshaft was severed and the tailrotor and tail rotor gearbox both separated from the vertical stabilizer. According to the manufacturer, an aircraft with the same serial number was registered as N8511F and was operated by Air America until it was reported destroyed in Viet Nam in 1966. This information was not reflected in the FAA aircraft data file.
failure of the pilot to verify that the load was properly rigged before attempting to pick it up. The uneven (sloping) terrain was a related factor.
Source: NTSB Aviation Accident Database
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