Incident Overview
A pilot was briefed prior to departure that thunderstorms were located north of the departure airport. While communicating with approach control, the pilot reported observing lightning ahead and inquired if the facility detected any weather ahead. The controller responded that the facility did not have weather radar but suggested a heading to fly, followed by another heading.
Loss of Contact
While on the second heading, the pilot advised that the flight was experiencing climbing and descending. Subsequently, radar and radio contact with the aircraft were lost.
Examination Findings
Post-accident examination of the aircraft revealed that the right wing had separated just outboard of the tiedown ring due to overstress. The aircraft was not equipped with weather radar. Examination of the engine and vacuum pump found no evidence of preimpact failure or malfunction.
The attitude indicator, directional gyro (DG), and turn coordinator were removed for testing. The turn coordinator tested satisfactorily, and there was no evidence of failure or malfunction of the attitude indicator. The DG was disassembled, revealing that a screw securing a weight attached to the rotor housing assembly was loose.