Avia Stroitel AC-5M N263R accident near Bend, Oregon

Probable cause

A loss of control just after takeoff for reasons that could not be determined based on the available information.

NTSB analysis

The pilot was departing in the self-launching motorglider when the accident occurred. A witness stated that, once airborne, the glider began to climb rapidly. The glider then banked to the right and entered a “dive” to ground contact. Another witness stated that, shortly after takeoff, the glider “went directly vertical” then banked to the right before diving toward the ground.

The glider came to rest on airport property near the departure end of the runway and was almost entirely consumed by postimpact fire, except for the left wing. The glider was not examined, and the wreckage was disposed of before examination could take place.

The pilot’s experience in the accident glider was not determined. Autopsy revealed an implanted pacemaker/defibrillator that was not interrogated by the medical examiner. Although the condition of having an abnormal heart rhythm placed the pilot at increased risk of a sudden cardiac event, operational evidence does not suggest that such an event occurred, and it is unlikely that the pilot’s cardiovascular disease was a factor in this accident. Toxicology detected therapeutic levels of the antidepressant duloxetine in the pilot’s blood and the presence of the antidepressant amitriptyline and its active metabolite nortriptyline in the pilot’s liver tissue. Nortriptyline was also detected in cardiac blood, likely at therapeutic levels. Side effects of these medications include drowsiness and dizziness, especially when first starting the medications. The reason, duration of time he used the medication, and whether he had side effects from the medications are unknown; therefore, whether the effects of the pilot’s use of duloxetine and amitriptyline were a factor in this accident could not be determined.

The glider’s rapid climb after takeoff and subsequent vertical descent are consistent with an inflight loss of control; however, because the glider was not examined after the accident, whether a mechanical malfunction or anomaly contributed to the loss of control could not be determined based on the available information.

Text from the NTSB. Open the NTSB docket for WPR20LA201 for the full record.