ROCKWELL 112 — Mt Hood, OR

What happened

The pilot departed on a visual flight rules flight toward a nearby mountain with a summit elevation of 11,239 ft. After completing one orbit around the summit at a radial distance of about 3 miles, the pilot flew the airplane to within 1,500 ft horizontally for a second orbit.

As the airplane turned around the southern side of the mountain, it began to descend at a rate of about 2,500 ft per minute (fpm) and impacted an almost-vertical face of the mountain about 1,600 ft below the summit. Due to the treacherous and remote nature of the accident site, an on-scene examination could not be performed, and the airplane was not recovered from the site.

The airplane's flight path around the summit revealed significant ground speed variations consistent with the airplane encountering headwinds as it circled. The pilot was likely aware of the wind conditions aloft because he appeared to perform a heading correction during the first orbit, as wind likely pushed the airplane toward the mountain. This should have served as a cue for the pilot to prepare for terrain-induced downdrafts and turbulence and to avoid flying too close to the peak; however, he continued with the second pass. Atmospheric analysis indicated that the airplane was operating in an area of mountain wave conditions at the time of the accident, with modeling indicating the presence of rapid changes in horizontal wind speed. Vertical velocity data showed that the airplane likely encountered updrafts of between 100 and 300 fpm during its first orbit around the mountain, and downdrafts greater than 2,000 fpm during the second, closer orbit, significantly exceeding the airplane's 200-fpm climb performance for that altitude.

There was no evidence to suggest that the pilot obtained an official weather briefing before the flight. Had he done so, he would have been made aware of the winds aloft conditions, which indicated the likelihood of terrain-induced turbulence close to the mountain.

Review of the pilot's medical records indicated that he was experiencing ongoing back pain due to an injury. Toxicological testing indicated that he had been using oxycodone, mitragynine, and metoclopramide, all of which are sedating and impairing. The levels of oxycodone in his blood were considered impairing. Use of the stimulant modafinil suggested that the pilot was attempting to counter fatigue. Toxicology also indicated that the pilot had used marijuana; however, it could not be determined if the concentration would have been impairing or decreased his performance.

Given that multiple drugs involved were sedating or impairing both individually and combined, the pilot would most likely have experienced diminished decision-making ability, increased reaction times, and degraded motor skills. Thus, it is likely that the use of these drugs contributed to the accident.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.