Amateur-built FOKKER DR-1 TRIPLANE N152RB accident near Parker, Colorado

Probable cause

The pilot's loss of control of the airplane due to the airplane’s reduced climb performance during high density altitude operations.

NTSB analysis

The pilot departed the airport, made a left turn to the east, and climbed to an altitude of 6,700 feet mean sea level (msl) at a groundspeed of about 93 knots. About 5 minutes after departing the airport, the airplane initiated a left descending turn and disappeared off radar. Two witnesses who lived near the accident site heard the airplane approach. One witness said the engine sounded normal. As they went outside to see the airplane, the witnesses saw the airplane go over their house at a low altitude, and one witness went to the back of the house to continue to watch the airplane. After he got to the back of his house, the witness saw the airplane in a tight left descending spiral in about a 45-degree nose-down pitch angle.

A postaccident examination of the airplane did not reveal any preimpact anomalies that would have precluded normal operations. A review of weather conditions at the time of the accident revealed that the density altitude was about 8,250 feet. The elevation at the accident site was 6,170 feet msl. The high density altitude would have reduced the airplane’s climb performance by about 67 percent, which could explain the airplane’s reduced climb performance. When the pilot was interviewed 7 months after the accident occurred, he said he could not recall anything that occurred on the day of the accident. However, it is likely that the airplane stalled as a result of reduced airspeed and climb performance while operating at a high density altitude.

Text from the NTSB. Open the NTSB docket for CEN12FA572 for the full record.