What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-5)During cruise flight the pilot heard a loud bang as if something had hit the aircraft. The pilot made a precautionary landing at the nearest suitable location. Subsequent investigation revealed that maintenance personnel had inadvertently left a lifting device attached to the main rotor system after maintenance was performed. The pilot failed to detect the lifting device during preflight. The lifting device separated from the rotor system in flight and struck and damaged the main rotor blades.
As the FAA filed it
(-5)DURING CRUISE FLIGHT THE PILOT HEARD A LOUD BANG AS IF SOMETHING HAD HIT THE AIRCRAFT. THE PILOT MADE A PRECAUTIONARY LANDING AT THE NEAREST SUITABLE LOCATION. SUBSEQUENT INVESTIGATION REVEALED THAT MAINTENANCE PERSONNEL HAD INADVERTENTLY LEFT A LIFTING DEVICE ATTACHED TO THE MAIN ROTOR SYSTEM AFTER MAINTENANCE WAS PERFORMED. THE PILOT FAILED TO DETECT THE LIFTING DEVICE DURING PREFLIGHT. THE LIFTING DEVICE SEPARATED FROM THE ROTOR SYSTEM IN FLIGHT AND STRUCK AND DAMAGED THE MAIN ROTOR BLADES.