Aircraft Accident/Incident Report

Louie Lake, Idaho 83638
Wednesday, July 14, 2004 12:20 MDT

After the medical evacuation flight arrived at its designated landing zone (6,500 feet mean sea level/MSL), an out-of-ground-effect hover was accomplished to verify the aircraft's performance. The power check was good and a positive rate of climb was noted. After landing and the crew had exited the aircraft, the pilot departed the area to locate a landing zone closer to the pickup point of the crew and patient. A landing zone at the 6,600 foot level (MSL) was located 3/8 of a mile closer to the patient pickup point. While waiting to load the patient the pilot determined a takeoff could be made based on his review of the aircraft's takeoff performance data. After completing an in-ground-effect power check and initiating a vertical climbout, the pilot confirmed the helicopter would clear a 100 foot tree line as it began to transition forward. After clearing the tree line the pilot detected the aircraft lose all lift as the helicopter began to settle toward the approaching trees. Applying the remaining power, the RPM warning sounded, prompting the pilot to reduce collective, but only to realize that he was descending into approaching obstacles. Right pedal was applied in an attempt to return to the original point of departure, however, the rotor RPM had still not completely recovered and the aircraft continued to descend. The aircraft impacted a boulder, and with the RPM now fully recovered, the helicopter jumped back into the air. The aircraft then rotated 180 degrees before the pilot performed a hover autorotation. During the maneuver the tail rotor had impacted a tree branch which resulted in an 8 inch chord wise gash to one of the tail rotor blades. The pilot felt that as the helicopter was clearing the tree line it entered a downwind condition, a condition which he didn't anticipate, resulting in a reduced power margin with which to overcome the loss of lift. A weather reporting station located 7 miles west-northwest of the accident site reported the wind was variable at 3 knots. The density altitude was calculated to be 8,898 feet. The pilot did not assert that any mechanical malfunctions precipitated the accident.

The failure of the pilot to maintain rotor rpm and his inadequate recovery from a bounced landing. Factors contributing to the accident included the tailwind condition and the tree.