MIA98LA070

On February 3, 1998, at about 1600 eastern standard time, a Bell 206B, N26EA, registered to Action Helicopters Inc., operating as a 14 CFR Part 91 sightseeing flight, crashed while attempting to pick up to a hover at Watson Island, Miami, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The helicopter sustained substantial damage. The airline transport pilot and two passengers reported no injuries. The flight was originating at the time of the accident.

The pilot stated the helicopter was facing about 100 degrees with a known right crosswind. He increased collective pitch and the helicopter came off the ground left skid low. As he was applying right cyclic he encountered a gust of wind, and the helicopter continued to roll over on its side. When asked what caused the accident, the pilot stated he encountered dynamic rollover, and was unable to take corrective action before the helicopter rolled over.

Review of weather information obtained from Miami International Airport, for the time period of the accident, revealed no recorded record of turbulence, downdrafts, gusts, or windshear.

A review of Advisory Circular 90-97, Helicopter Dynamic Rollover states, an increasing percentage of helicopter accidents are being attributed to dynamic rollover, a phenomenon that will without immediate corrective action, result in destruction of the helicopter and possible serious injury....During normal or slope takeoffs and landings with some degree of bank angle or side drift with one skid/wheel on the ground, the bank angle or side drift can place the helicopter in a situation where it is pivoting (rolling) about a skid/wheel which is still in contact with the ground. When this happens, lateral cyclic control response becomes more sluggish and less effective for a free hovering helicopter. Consequently, if a roll rate is permitted to develop, a critical bank angle (the angle between the helicopter and the horizon) may be reached where roll cannot be corrected, even with full lateral cyclic, and the helicopter will roll over onto its side. As the roll rate increases, the angle at which recovery is still possible is significantly reduced. The critical rollover angle is also reduced. The critical rollover angle is further reduced under the following conditions:

a. Right side skid down condition; b. Crosswinds; c. Lateral center of gravity offset; d. Main rotor thrust almost equal to helicopter weight; and e. Left yaw inputs.