Smyrna, TN, USA
N9235
Enstrom F-28A
The pilot stated he reduced the collective from 23 inches of manifold pressure to 21 inches of manifold pressure to initiate a descent for landing, and it "felt like the engine was shuddering." He stated he increased the manifold pressure to 23 inches, and the engine "seemed to smooth out." He stated he entered a left base, then turned final and reduced the manifold pressure. On final approach, the pilot slowed the helicopter to approximately 10 miles per hour, and when he added more collective, he saw the "rpm drop to the bottom of the green." He stated he "dropped collective and added throttle." He stated the helicopter would not maintain altitude, and he attempted a run-on landing in the grass; the left skid contacted the ground and collapsed, and the helicopter rolled over onto its left side. Examination revealed the forward and aft left skid struts were bent inboard approximately 135 degrees. Two main rotor blades were bent downward and were delaminated near the root and on the trailing edge of the blades. The third main rotor blade was bent upward near the tip, and trailing edge and upper skin deformation was observed. Continuity for the tail rotor, cyclic, collective, over-running clutch, throttle, and mixture controls was established. Examination of the drive belt revealed a shaved area in the vicinity of the clutch assembly, and the over-running clutch operated. The fan shroud displayed circumferential scoring. An engine start was attempted by utilizing the cockpit engine controls. The engine started, then idled smoothly. Higher rpm settings were not attempted.
On November 21, 2004, at 1811 central daylight time, an Enstrom F-28A, N9235, registered to and operated by the private pilot, collided with the ground and rolled over during an attempted run-on landing at Smyrna Airport, Smyrna, Tennessee. The personal flight was operated under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual meteorological conditions prevailed. The private pilot reported no injuries, and the helicopter sustained substantial damage. The flight departed Franklin Wilkins Airport, Lexington, Tennessee, about 1630 on November 21, 2004. The pilot stated he was in cruise flight at 2500 feet mean sea level (MSL) approximately 7 miles from the Smyrna Airport when he initiated a descent for landing. He stated he reduced the collective from 23 inches of manifold pressure to 21 inches of manifold pressure, and it "felt like the engine was shuddering." He stated he descended the helicopter to pattern altitude and increased the manifold pressure to 23 inches, and the engine "seemed to smooth out." He stated he entered a left base for runway 32, then turned final and reduced the manifold pressure. The pilot stated he slowed the helicopter to approximately 10 miles per hour, and when he added more collective, he saw the "rpm drop to the bottom of the green." He stated he "dropped collective and added throttle to try to bring manifold up while maintaining rpm. Tried this a couple of times with no luck." He stated the helicopter would not maintain altitude, and he maneuvered it to the left of the approach lights and attempted a run-on landing in the grass. The pilot stated helicopter's left skid "hung in the dirt and collapsed," and the helicopter rolled over onto its left side. Examination revealed the helicopter came to rest on its left side in a level, grassy area beside the approach lights 217 feet short of the runway 32 threshold. The forward and aft left skid struts were bent inboard approximately 135 degrees, the left horizontal stabilizer was crushed, and the tail boom was buckled. Fuel was observed in the fuel tank. One main rotor blade was bent downward approximately 45 degrees in an arcing bend along the length of the blade. Trailing edge deformation was observed along the length of the blade, and approximately two to three feet of the trailing edge near the blade root was delaminated. The walking beam bracket and the bracket attachment bolt were broken, and the push-pull tube upper rod end was pulled out. The second main rotor blade was bent downward approximately 45 degrees in an arcing bend along the length of the blade. Trailing edge deformation was observed along the length of the blade; approximately one foot of the trailing edge near the blade root was delaminated, and the trailing edge from the inboard tab to the tip was delaminated. The walking beam bracket was broken. The third main rotor blade was bent upward approximately 5 to 10 degrees near the tip; trailing edge and upper skin deformation was observed. The bottom pitch link rod end was separated. Continuity for the tail rotor, cyclic, collective, clutch, throttle, and mixture controls was established. Examination of the drive belt revealed a shaved area in the vicinity of the clutch assembly, and the over-running clutch operated. The fan shroud displayed circumferential scoring. An engine start was attempted by utilizing the cockpit engine controls. The engine started, then idled smoothly. Higher rpm settings were not attempted. A review of maintenance logs for the helicopter revealed an annual inspection was completed November 20, 2004, at a hobbs meter reading of 1273.0, airframe total time of 2415.3, and engine time since major overhaul of 340.3 hours. The records revealed a major overhaul of the helicopter's engine was completed November 4, 1992. The hobbs meter reading at the accident site was 1285.9.
The loss of engine power for undetermined reasons, and the pilot's improper flare during forced landing, which resulted in an inflight collision into an open field.
Source: NTSB Aviation Accident Database
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