Aircraft: Zenair CH 2000. Injuries: 2 Fatal. Location: Nephi, Utah. Aircraft damage: Destroyed.
What reportedly happened: Several people on the ground saw the airplane flying low in the airport pattern during a thunderstorm. As the plane turned from a crosswind to a downwind leg, airplane stalled at an altitude of approximately 150 feet, pitched down and crashed.
A regional radar mosaic for the time of the accident depicted several scattered weather echoes with one defined cell of moderate-to-strong intensity just over the accident site. Archived lightning data for the time revealed seven in-cloud and cloud-to-ground lightning flashes within a 50-mile radius of the accident site, however no cloud-to-ground lightning strikes were detected within 15 miles. The detection of lightning confirmed the presence of a cumulonimbus cloud in the area.
Wreckage and impact signatures were consistent with a right-wing-low and nose-low impact. Based on the witness observations and recorded weather data, it is likely that, as a result of the approaching thunderstorm, the airplane encountered a microburst or downdraft that exceeded its climb performance and resulted in a loss of airplane control.
Probable cause: The pilot’s inability to maintain airplane control due to an encounter with a microburst/downdraft that exceeded the climb performance capabilities of the airplane.
NTSB Identification: WPR12FA378
This August 2012 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.