NTSB Identification: MIA98LA254.
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Accident occurred Tuesday, September 29, 1998 in OXFORD, MS
Probable Cause Approval Date: 03/31/2000
Aircraft: Bell 47-D1, registration: N755E
Injuries: 1 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
No discrepancies were found during the preflight. Shortly after takeoff, about 400-500 feet agl, the pilot felt a short duration minor vibration in the cyclic. The vibration increased in intensity but reduced when collective was lowered. He flew towards a clearing but with obstructions in the flight path, he intentionally collided with trees. Weeks earlier, the pilot noted a crack in the laminate on the top of the 'blue' main rotor blade which progressed thru to the bottom of the blade. Two mechanics inspected the blade; one determined that water was present, the other reported that the crack was only in the laminant. A mechanic repaired the crack by applying a two-part adhesive externally to cover the crack. According to the helicopter maintenance and overhaul instructions manual, there was no mention that epoxy type material can be applied to the surfaces of the fiberglass cloth that was damaged. Post accident examination of the flight controls revealed no evidence of preimpact failure or malfunction. Examination of the blue main rotor blade revealed a segment of blade missing but no determination could be made as to the reason for the separation.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to maintain directional control due to vibration from the main rotor blade for undetermined reasons. A related finding was the improper repair of a crack in the laminant of the blue main rotor blade by other maintenance personnel. Full narrative available
Index for Sep1998 | Index of months