On September 24, 2010, at 1634 eastern daylight time, an American Eurocopter AS-350B2, N91DK, operated by the Dekalb County Police, was substantially damaged after a loss of control while landing at Covington Airport (9A1), Covington, Georgia. The certificated commercial pilot and the certificated flight instructor sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local public use instructional flight.

The flight instructor reported to witnesses, police, and to a Federal Aviation Administration (FAA) inspector that he and the pilot had been performing hydraulics-off maneuvers, the helicopter "got away from them," and control could not be regained prior to ground contact.

According to the pilot, he was conducting recurrent training with the instructor, a contractor, who was not affiliated with the Dekalb County Police. He said they had returned from a meal break, and that this was the second flight of the day.

According to the pilot, the instructor simulated a hydraulics failure by "turning off" the flight control hydraulics switch, and he was to then perform a hydraulics-off, run-on landing as the remedial action to the simulated emergency. As the helicopter slowed over the runway, the nose yawed to the left, and the pilot was unable to correct the yaw with right pedal input. The instructor announced and took control of the helicopter, and completed a low-level, left-hand orbit to demonstrate and complete the maneuver.

According to the pilot, as the helicopter completed the left orbit and lined up for landing, it "rolled wings level" but then continued to roll to the right and collided with terrain. He said that the entire maneuver was conducted hydraulics-off, and that he felt the instructor had control of the helicopter until it rolled past wings-level to the right. The pilot added that the instructor had successfully completed a similar maneuver earlier in the day, without restoring the flight control hydraulics.

Both the pilot and the instructor stated that there was nothing wrong with the performance and handling of the helicopter.

The pilot held a commercial pilot certificate with a rating for rotorcraft helicopter. His most recent FAA second class medical certificate was issued July 14, 2010. The pilot reported 929 total hours of flight experience, of which 929 hours were in the accident helicopter make and model.

The flight instructor held a commercial pilot certificate with ratings for airplane single engine, multiengine, rotorcraft-helicopter, and instrument airplane and helicopter. He held a flight instructor certificate for airplane single engine, rotorcraft-helicopter, and instrument airplane and helicopter. His most recent FAA second class medical certificate was issued April 12, 2010. The instructor reported 4,100 total hours of flight experience on that date.

According to the operator, the helicopter had accrued 3,158 total aircraft hours. Its most recent 100-hour inspection was completed on August 12, 2010, at 3,100 total aircraft hours.

At 1650, the weather reported at LZU, 21 miles north of the site, included scattered clouds at 5,500 feet and winds from 200 degrees at 5 knots. The visibility was 10 miles. The temperature was 32 degrees Celsius (C) and the dew point was 21 degrees C. The altimeter setting was 30.09 inches of mercury.

Examination of the helicopter by an FAA inspector revealed the helicopter sustained substantial damage to cockpit, cabin structure, and landing gear.

According to the Eurocopter AS 350 B2 Flight Manual (Emergency Procedures) and Flight Manual Supplement, Hydraulic Pressure Failure Training Procedures, "CAUTION: DO NOT ATTEMPT TO CARRY OUT HOVER FLIGHT OR ANY LOW SPEED MANEUVER WITHOUT HYDRAULIC PRESSSURE ASSISTANCE. THE INTENSITY AND DIRECTION OF THE CONTROL FEEDBACK FORCES WILL CHANGE RAPIDLY. THIS WILL RESULT IN EXCESSIVE PILOT WORKLOAD, POOR AIRCRAFT CONTROL, AND POSSIBLE LOSS OF CONTROL."