What happened
The aircraft departed Palomar Airport (CRQ) in Carlsbad, California, for a local instructional flight. This sortie marked the second flight for a dual student pilot. Following the completion of the scheduled flight lesson, the student requested that the Certified Flight Instructor (CFI) demonstrate hovering techniques.
The instructor initiated an autorotation maneuver and planned to execute a power-on recovery over Batiquitos Lagoon. This location is characterized as a high, brush-covered marshy swamp area. Upon completing the recovery from the autorotation, the instructor attempted to transition into forward flight. During this phase, the helicopter's skids made contact with the dense, high vegetation.
The impact caused the aircraft to pitch downward and aft. The pilot was unable to arrest the downward momentum using the cyclic control. Consequently, the main rotor blades struck the ground.