Amateur-built GLASAIR III accident near Big Bear City, California, November 21, 2021

The NTSB's narrative final · quoted from the NTSB record

The pilot departed on a cross-country flight in the experimental, amateur-built airplane under day visual meteorological conditions. He was reported missing the following day, and the wreckage was subsequently discovered along the route of flight near the summit of a mountain at an elevation about 9,720 ft mean sea level (msl). Automatic dependent surveillance – broadcast (ADS-B) data revealed that the pilot departed and climbed the airplane to an altitude about 9,500 ft msl on an easterly heading and roughly maintained this heading and altitude for the duration of the flight until impact. Both the ADS-B data and distribution of the wreckage were consistent with controlled flight into terrain in a near-level attitude with a high forward velocity and revealed no evidence of evasive action before impact. The scope of the wreckage examination was limited due to the location of the accident site; however, all major components of the airplane were identified at the site. Additionally, ADS-B data was not consistent with the pilot experiencing a flight control or engine anomaly before the accident. Whether the pilot may have experienced physiological incapacitation or impairment during the flight could not be determined based on the available information. No blood samples were available for toxicological testing; therefore, carboxyhemoglobin levels could not be determined. Testing of available muscle tissue indicated the pilot’s use of the sedating antihistamine doxylamine; however, this result could not be used to determine whether the drug had sedating or impairing effects that may have contributed to the accident.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.