What happened
On October 1, 2008, at approximately 1840 Pacific daylight time, a Eurocopter AS350 B3, registration N172AE, experienced a hard landing at Blaine Municipal Airport in Blaine, Washington. The aircraft, operated by Customs and Border Protection, was conducting an annual proficiency evaluation flight involving practice emergency procedures. The flight originated from Bellingham, Washington, at 1815.
During the downwind leg to runway 32, the flight instructor switched the governor from auto to manual to practice manual governor operations. After completing a left 360-degree turn, the pilot began an approach intended for a slide-on landing. To achieve a flatter approach profile, the pilot increased the rate of descent. At approximately 80 feet above ground level, the pilot increased throttle and slightly raised the collective. Shortly after, the rotor RPM began to decay below the green arc. As the rotor RPM approached 360 rpm, the low rotor RPM warning horn sounded. The pilot applied throttle, and the RPM stabilized at 350 rpm at an altitude of about 40 feet above ground level. As the helicopter descended through 20 feet above ground level, the pilot attempted to increase throttle and collective to arrest the descent, but the aircraft landed hard on the asphalt runway in a slight nose-high attitude. The pilot and flight instructor were not injured.
The investigation
An inspection conducted by a Federal Aviation Administration inspector revealed that the tail boom was partially bent and one main rotor blade was damaged. No mechanical anomalies were reported by the crew prior to the impact.