Event Description
Two helicopters were operating in close proximity. The pilot of the first helicopter reported warning the second pilot about a flock of birds and stated that he had to bank sharply to avoid them. Receiving no reply, he turned around but could no longer see the other helicopter. Witnesses then heard a loud noise and observed an object detach from the second helicopter. That helicopter subsequently struck the ground in an inverted orientation in the backyard of a residence.
Physical Evidence
Investigators located the left synchronized elevator and its end cap approximately 240 feet from the main wreckage. Examination of the main rotor blades revealed an indentation on the leading edge of one blade that matched the shape of the end cap, indicating physical contact between the two components during flight.
Witness and Pilot Accounts
The first pilot's warning about birds was not acknowledged by the second pilot. The first pilot further noted that he had to maneuver aggressively to avoid the birds himself. After losing visual contact with the second helicopter, he searched but did not find it. Witnesses on the ground reported hearing a loud noise and seeing a piece separate from the helicopter, followed by the inverted impact.
Conclusion
The investigation documented the separation of the left synchronized elevator and end cap, the impact of the helicopter in an inverted attitude, and the contact evidence on the rotor blade. No official probable cause has been determined.