Bell 47 Safety Record

IMPROPER MAINTENANCE AND INSPECTION OF THE CARBURETOR SYSTEM BY MAINTENANCE PERSONNEL DURING THE LAST ANNUAL INSPECTION WHICH RESULTED IN A PARTIAL LOSS OF ENGINE POWER DUE TO CARBURETOR ICE. CONTRIBUTING TO THE ACCIDENT WERE: THE PILOT'S FAILURE TO PERFORM AN ADEQUATE PREFLIGHT AND ENGINE RUN-UP, AND THE CARBUETOR ICING CONDITIONS.

failure of the pilot to maintain lateral control of the helicopter, while hovering in preparation for a precautionary landing next to a ship at sea. Factors relating to the accident were: the passenger's premature evacuation from the helicopter, and the resultant lateral imbalance of the helicopter as the passenger jumped.

the pilot's failure to maintain clearance from the power lines due to his improper takeoff technique. A factor was the helicopter induced blowing dust which impaired the pilot's visibility.

the failure of the pilot and company maintenance personnel to detect a crack in the clevis ears during the required daily inspection and the recent annual inspection. A factor in the accident was the improper welding and stress relief procedure used to assemble the components, which induced high residual stresses in the clevis ears and led to fatigue cracking of the part.

the student pilot's abrupt touchdown while landing in a field. Related factors are the student pilot's failure to attain the proper descent rate during the approach to landing, and the flight instructor's inadequate supervision of the student.

plot misjudged the flare. The factors included the pilot getting too close to the lead helicopter, allowing his airspeed to get too slow, and encountering settling with power.

failure of the collective yoke bearing, which resulted in an uncontrolled descent and collision with trees. A factor relating to the accident was: the manufacturer's inadequate inspection interval of the yoke bearing.

THE FAILURE OF COMPANY MAINTENANCE PERSONNEL TO PERFORM ADEQUATE INSPECTIONS OF THE HELICOPTER, AND THE FAILURE OF THE CYCLIC CONTROL ROD DUE TO CORROSION.

loss of power as a result of an intake valve failure due to improper maintenance performed during the major engine overhaul, and pilot misjudgment of the flare during autorotation.

the pilot's improper handling of the helicopter by her failure to maintain an adequate airspeed for the attempted maneuver resulting in an uncontrolled descent and subsequent collision with the ground.

clutch slippage for undetermined reasons. A factor in the accident was the helicopter's low above ground altitude, which limited the pilot's time and ability to recover main rotor rpm.

INADVERTENT INSTALLATION OF AN UNAPPROVED PART (TAIL ROTOR GEAR/DRIVE ASSEMBLY), THAT BECAME EXCESSIVELY WORN SINCE IT DID NOT CONFORM TO THE MANUFACTURER'S SPECIFICATION, RESULTING IN FAILURE OF THE ASSOCIATED TAIL ROTOR BEARING (ALSO AN UNAPPROVED PART), LOSS OF CONTINUITY (DISCONNECT) OF THE TAIL ROTOR DRIVE SYSTEM, AND A FORCED AUTOROTATION INTO AN AREA WITH TREES.

the pilot's failure to maintain airspeed during a low altitude aerial application turn, which resulted in inadvertent settling with power and the subsequent collision with the terrain.

INFLIGHT COLLISION WITH A POWER TRANSMISSION ARRAY STATIC LINE WHEN THE FLIGHT INSTRUCTOR AND DUAL (PRIVATE PILOT) STUDENT FAILED TO MAINTAIN ADEQUATE VISUAL LOOKOUT.