Event WPR21LA071

Factual narrative

On November 17, 2020, about 1418 Pacific standard time, an experimental amateur-built Co-Z COZY airplane, N82V, sustained substantial damage when it was involved in an accident in Compton, California. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, approximately 3 minutes after departure, at an altitude of 1,500 ft., the engine started to “run rough” so he decided to return to the airport. During the landing roll, the airplane bounced, veered off the runway, and ground looped. The left main landing gear separated from the airplane during the accident sequence. The pilot reported to a Federal Aviation Administration (FAA) inspector that when he opened the engine cowling after the accident, he noticed a spark plug on the bottom of the engine compartment. A postaccident examination of the airplane by the FAA inspector confirmed the No. 2 cylinder bottom spark plug was laying loose in the engine compartment with the ignition lead still attached. The spark plug threads and corresponding threads in the cylinder displayed no signs of damage. The engine was repaired in December 2019 and reinstalled on the airplane. The airplane accumulated approximately 8 hours since the maintenance. Approximately 3 minutes after departure, at an altitude of 1,500 ft, the airplane’s engine experienced a partial loss of power, and the pilot initiated a return to the airport. During the landing roll, the airplane bounced, veered off the runway, and ground looped. A postaccident examination of the airplane revealed the No. 2 cylinder bottom spark plug was laying loose in the engine compartment with the ignition lead still attached. The spark plug threads and corresponding threads in the cylinder displayed no signs of damage, which was consistent with the improper installation of the spark plug. The engine was repaired about 11 months before the accident, which is likely when the spark plug was improperly installed. The airplane accumulated approximately 8 hours since the maintenance. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).

• — Aircraft-Aircraft power plant-Ignition system-Spark plugs/igniters-Not installed/available
• — Personnel issues-Task performance-Maintenance-Installation-Maintenance personnel