Cessna 421C N67SR accident near Wells, Texas

Probable cause

The pilot’s decision to continue the flight into an area of extreme weather, which led to the in-flight encounter with a thunderstorm and structural failure of the wings and tail.

NTSB analysis

While in cruise flight, the twin-engine airplane encountered a severe thunderstorm that likely contained hail up to 1.25 inches in diameter. After penetrating the thunderstorm, the airplane's structure failed, which was evidenced by the pieces of the airplane being found up to 0.6 mile away from the main wreckage. The horizontal tail, which was found 0.25 mile from the main wreckage, had dents on the upper surface that were consistent with in-flight hail damage. The left horizontal stabilizer had failed in an upward direction, and the right horizontal stabilizer had failed in a downward direction, consistent with an extreme left roll rate. In addition, both left and right outboard wing sections were partially separated from the remainder of the wing. Although there was no record of the pilot having obtained a FAA weather briefing, it was not possible to determine if the pilot used other sources to obtain weather information prior to the flight. Records of in-flight communications indicated that the pilot was advised of adverse weather, including thunderstorms and moderate, heavy, and extreme precipitation about 15 minutes before his last transmission. At that time, the airplane was 40 miles from the storm. In addition, the pilot confirmed during communications that the airplane was equipped with on-board weather radar (which provided real-time weather), and the controller authorized him to deviate course, if necessary.

Text from the NTSB. Open the NTSB docket for CEN13FA073 for the full record.