What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.4)An hour after landing in an open field (6,200 feet MSL) near Parkman, Wyoming, in the bighorn national forest, the pilot performed a practice takeoff without his passenger to test the aircraft's performance. The helicopter hovered normally after effective translational lift was achieved, and he climbed out at 40 knots. Shortly after clearing a 75-foot ridge 100 to 150 yards from the takeoff field just after coming out of ground effect, the aircraft experienced a downdraft and subsequently began to lose altitude. The power required for the helicopter to climb was greater than the power available. The aircraft impacted the ground through 60 to 80 feet of trees, and came to rest in an inverted position. According to the pilot, there were no mechanical problems and the engine was running on impact. Density altitude at the time of the accident was calculated to be 7,578 feet. According to calculated weight and performance data, the gross weight of the aircraft at the time of departure was approximately 1,232 lbs. At an indicated airspeed of 35 knots, the maximum obstacle clearance height was calculated to be 75 feet, with a maximum distance of 800 feet. (-23)pilot lost control of helicopter during takeoff and climb in high density altitude conditions.
As the FAA filed it
(.4)AN HOUR AFTER LANDING IN AN OPEN FIELD (6,200 FEET MSL) NEAR PARKMAN, WYOMING, IN THE BIGHORN NATIONAL FOREST, THE PILOT PERFORMED A PRACTICE TAKEOFF WITHOUT HIS PASSENGER TO TEST THE AIRCRAFT'S PERFORMANCE. THE HELICOPTER HOVERED NORMALLY AFTER EFFECTIVE TRANSLATIONAL LIFT WAS ACHIEVED, AND HE CLIMBED OUT AT 40 KNOTS. SHORTLY AFTER CLEARING A 75-FOOT RIDGE 100 TO 150 YARDS FROM THE TAKEOFF FIELD JUST AFTER COMING OUT OF GROUND EFFECT, THE AIRCRAFT EXPERIENCED A DOWNDRAFT AND SUBSEQUENTLY BEGAN TO LOSE ALTITUDE. THE POWER REQUIRED FOR THE HELICOPTER TO CLIMB WAS GREATER THAN THE POWER AVAILABLE. THE AIRCRAFT IMPACTED THE GROUND THROUGH 60 TO 80 FEET OF TREES, AND CAME TO REST IN AN INVERTED POSITION. ACCORDING TO THE PILOT, THERE WERE NO MECHANICAL PROBLEMS AND THE ENGINE WAS RUNNING ON IMPACT. DENSITY ALTITUDE AT THE TIME OF THE ACCIDENT WAS CALCULATED TO BE 7,578 FEET. ACCORDING TO CALCULATED WEIGHT AND PERFORMANCE DATA, THE GROSS WEIGHT OF THE AIRCRAFT AT THE TIME OF DEPARTURE WAS APPROXIMATELY 1,232 LBS. AT AN INDICATED AIRSPEED OF 35 KNOTS, THE MAXIMUM OBSTACLE CLEARANCE HEIGHT WAS CALCULATED TO BE 75 FEET, WITH A MAXIMUM DISTANCE OF 800 FEET. (-23)PILOT LOST CONTROL OF HELICOPTER DURING TAKEOFF AND CLIMB IN HIGH DENSITY ALTITUDE CONDITIONS.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.