NTSB Probable Cause

THE PILOT MISJUDGED CLEARANCE BETWEEN HER EXTERNAL LOAD AND THE OBSTRUCTION. FACTORS RELATED TO THE ACCIDENT WERE: THE OBSTRUCTION, IMPROPER MAINTENANCE AND MODIFICATION OF THE EXTERNAL LOAD LINE/HOOK BY THE OPERATOR, FAILURE OF THE PILOT TO JETTISON THE EXTERNAL LOAD, AND A FAILURE OF THE OPERATOR MANAGEMENT TO ASSURE THE PILOT HAD RECEIVED ADEQUATE TRAINING/CERTIFICATION.