Cessna 170B N6073V accident near Anchorage, Alaska

Probable cause

The pilot’s decision to make an abrupt and steep low altitude turn just after takeoff, while attempting to return to his departure airport, resulting in an aerodynamic stall and loss of aircraft control. Contributing to the accident was the pilot’s failure to ensure that the airplane’s engine access cowling was properly latched before takeoff.

NTSB analysis

The private pilot was departing on a Title 14, CFR Part 91, personal flight. Witnesses reported that shortly after it became airborne, the right engine access cowling opened, and the airplane began a steep left turn back to the airport. As the airplane’s left bank increased, it descended nose first into tundra-covered terrain. The pilot said he could not specifically recall latching the cowling after preflighting the airplane, and that he should have climbed the airplane higher before returning to the airport. Examination of the airplane did not disclose any preimpact mechanical malfunction. Given the lack of mechanical deficiencies with the airplane's engine or flight controls, in conjunction with the witness and the pilot’s statement, it is likely the pilot failed to properly latch the engine access cowling before takeoff, then failed to adequately maintain control of the airplane while returning to the airport after the cowling opened.

Text from the NTSB. Open the NTSB docket for ANC09LA088 for the full record.