20010408006929A

(-23) On April 8, 2001, at 0945LT, a Bell BHT-208-B attempted to land in a private yard one mile north of the danville regional airport (dan) in Virginia. The pilot conducted a normal approach to an area approx. 350 feet to the west of the desired landing site. He then hovered upslope (slope 7 degrees) east and turned the a/c to the north, and attempted to conduct a slope landing. There were trees in front of and to the right side of the a/c in close preoximity. The a/c was drifting to the left (west) as the skids touched down. The left skid dug into the soft turf and the a/c rolled onto its left side. The main rotor made ground contact and broke into several pieces. The mast sheared and a portion of the main rotor blade was thrown approx.871 feet from the impact site. The helicopter was substantially damaged. (.19)on April 8, 2001, at 0945 eastern daylight time, a Bell 206B, N17HA, was substantially damaged when it rolled over during landing on private property in Ringgold, Virginia. The certificated commercial pilot/owner and passenger sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight conducted under 14 cf r part 91. In a telephone conversation, the pilot said he had flown into danville airport, danville, Virginia, on the morning of the accident with three passengers. When he arrived in danville, he dropped off his passengers and prepared to take his friend on a local flight. The pilot and new passenger departed the airport, and flew to another friend's home where he planned to land in the backyard. The pilot stated he had landed in his friend's backyard on several occasions when he owned a Hughes 269B. The pilot approached his friend's property at a slow hover about 300 feet away from his friend's house, and taxied upslope into the backyard. He made a 90 degree left pedal turn over the landing area, so he was parallel to the slope. The pilot then set the right (uphill) skid down first. When the right skid made contact with the ground, the helicopter began to longitudinally rock back and forth. The pilot stated that the rocking motion startled him, and he lifted the helicopter back into the air. When he did this, the helicopter nosed forward. To counteract the nose down attitude, the pilot applied aft cyclic, but it did not arrest the situation. According to the pilot, there were trees directly in front of him and he was concerned about hitting them. To avoid striking the trees, he "dropped" the collective to set the helicopter down again, which resulted in the helicopter landing on the front part of the skids. The helicopter then rolled forward onto its nose, and came to rest on its left side. (.4) the pilot/owner prepared to land on an estimated 7 degree slope with the right/uphill skid first. When the right skid made contact with the ground, the helicopter began to rock back and forth longitudinally. The pilot then lifted the helicopter back up into the air, but it nosed forward. To counteract the nose down attitude, the pilot applied aft cyclic, but it did not arrest the situation. The pilot was then concerned about striking trees that were directly in front of him, so he "dropped" the collective to set the helicopter down again. However, the helicopter landed on the front part of the skids, and rolled over onto its nose, and came to rest on its left side. According to advisory circular 90-87-helicopter dynamic rollover, "during normal or slope take-offs and landings with the same degree of bank angl e or side drift with one skid on the ground, the bank angle or side drift can place the helicopter in a situation where it is pivoting (rolling) about a skid, which is still in contact with the ground. When the uphill slope skid hits the ground, the dynamics of the motion can cause the helicopter to bounce off the upslope skid, and the inertia can cause the helicopter to roll about the downslope ground contact point and over onto its side. The collective should not be pulled suddenly to get airborne, as a large and abrupt rolling moment in the opposite direction will result. This movement can be uncontrollable. If the helicopter develops a roll rate with one skid on the ground, the helicopter can roll over on its side." The pilot reported that there were no mechanical deficiencies.