A109 All Series
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 42.6; Flight Crew Total 4845; Flight Crew Type 33
Inflight Event / Encounter Object
General Maintenance Action
Environment - Non Weather Related
While flying a passenger from a private golf course to their destination and then returning to my point of origin with no passengers I encountered some sort of string (like kite string) in the rotor head of my helicopter.  I am not sure as to where the incident occurred as the string in the rotor head was not discovered until on the ground after shutdown.  At no point on my flight was I at any unusually low altitudes; most of the time I did have clearance from Tower to be at 1;000 feet or higher on the assigned helicopter routes.  The weather was clear and the visibility was unrestricted.  If it was a kite that I flew through it had to be flying extremely high.  As stated earlier; I did not see or hear anything unusual.  I did not experience any unusual control loads and the helicopter gave no indication that anything was tied up in the rotor. After shutdown of the aircraft back on the golf course I saw a small piece of string in the rotor head on my post flight walk around.  Upon climbing up to the top of the helicopter I discovered a few hundred feet of string tied around the swashplate.  I informed Maintenance and we began the process of inspecting the aircraft for any damage. I informed my passenger that there was going to be a delay for an undetermined amount of time and told him to find another means of transportation.
The pilot of an AW109 helicopter noticed string on the main rotor head during the post flight inspection.