ATL06LA085
ATL06LA085

On May 26, 2006, at 1127 eastern daylight time, a Hughes 269A, N269RS registered to Salisbury Helicopters Inc. and operated by Horizon Helicopter Service, as a 14 CFR Part 91 Instructional flight, rolled over during a forced landing near Concord, North Carolina. The helicopter received substantial damage. Visual meteorological conditions prevailed and no flight plan was filed. The certified flight instructor (CFI) and student pilot reported no injuries. The flight originated from Concord Regional Airport, Concord, North Carolina on May 26, 2006 at 1100.

The student pilot stated that he was practicing for his check ride along with his CFI, and was preparing for a simulated engine failure. He stated that he had the flight controls and counted down "3,2,1 and cracked the throttle from 2900 rpm to 2400 rpm." However, the engine "died" and the CFI took over the controls. The CFI entered an autorotation and maneuvered the helicopter into an uneven field. The student pilot then stated that the "CFI flared the helicopter, and when the helicopter hit it flipped onto the right side.'' The CFI turned off the fuel boost pump, exited the helicopter and helped the student pilot out of the helicopter.

The CFI stated that he was conducting a training flight with the student pilot. They found an open field to practice settling with power maneuvers and simulated engine failures. During the simulated engine failure the student pilot decreased the engine rpm and it went to "0 rpm". The CFI stated that he took over the flight controls, and entered an autorotation into the open field. Upon touch down the helicopter rolled over on to its right side. The CFI did not report any flight control anomalies prior to the accident.

Examination of the helicopter by an FAA inspector revealed that the helicopter was resting on its right side. The main rotor blades were broken outboard of the main rotor head. The tail boom was buckled and remained attached to the fuselage. The right side skid was bent outward and damaged. The upper right side of the cockpit was buckled. Mechanical continuity was established between the main rotor and tail rotor. Mechanical continuity was also established in primary and anti-torque controls. Movement of the cyclic stick resulted in appropriate movement of the rotor head. Throttle and mixture continuity was verified on both controls.

Examination of the logbooks by an FAA inspector and airframe & powerplant mechanic revealed the helicopter had a total airframe time of 14398.3 flight hours, and a total of 69.7 flight hours since the annual inspection. The annual inspection was conducted on March 26, 2006. A 205-horsepower Lycoming HIO-360-B1A engine (serial number RL-5683-51A) powered the helicopter. The engine had 562.2 hours since major overhaul.

Examination of the clutch linear actuator revealed it was engaged. The fuel shut-off valve was "on", and the mixture control was full rich. The fuel servo, fuel pump, fuel strainer, and all associated fuel lines were undamaged. The ignition wiring harness, magnetos (LH and RH), oil lines, oil filter, and overall engine was undamaged. There were approximately 6.25 quarts of oil in the engine at the time of inspection. The oil was drained from the engine and examined. It revealed no signs of contamination. The oil filter was cut open and the paper element was inspected. No foreign matter or contamination was observed in the filter. A fuel sample was taken and was blue in color and uncontaminated. The throttle control, mixture control and fuel shut off valve operated correctly.

The upper and lower spark plugs were removed for examination. All plugs appeared normal in accordance with the Champion Check-A-Plug chart, and were gapped correctly. A cold cylinder compression check was performed and the results were: #1-62/80, #2-70/80, #3-72/80, and #4-62/80. The left and right magneto timing was checked and found set correctly at 25-degrees BTDC.

A review of Advisory Circular 90-87, 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.





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