Primary finding
Probable cause
The pilot’s inadvertent flight into icing conditions, which resulted in the accumulation of structural icing and an aerodynamic stall.
Investigator assessment
Analysis narrative
The pilot reported that, while operating in instrument meteorological conditions, the airplane started accumulating ice on the wings and windshield. He informed air traffic control (ATC) and requested to be diverted. ATC vectored him to a nearby airport for an instrument approach. Following completion of the instrument approach, while the airplane was about 10 ft above ground level, the airplane stalled and then landed hard on the runway. The pilot taxied the airplane to the ramp without further incident. The airplane sustained substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The Federal Aviation Administration's Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25B, provides information and guidance in a section titled, "Stalls," which stated, in part, that "as little as 0.8 millimeter of ice on the upper wing surface increases drag and reduces aircraft lift by 25 percent."
Source record
Factual narrative
The pilot reported that, while in instrument meteorological conditions (IMC) the airplane started accumulating ice on the wings and windshield. He informed air traffic control (ATC) and requested to be diverted. ATC vectored him to a nearby airport for an instrument approach. Following completion of the instrument approach, while the airplane was about 10 ft above the runway, the airplane stalled and landed hard on the runway. The pilot taxied to the ramp without further incident. The airplane sustained substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The Federal Aviation Administration's Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25B, provides information and guidance in a section titled "Stalls" which stated in part: As little as 0.8 millimeter of ice on the upper wing surface increases drag and reduces aircraft lift by 25 percent.