ATL06LA134 · Cirrus Design Corp SR22-GTS

The airplane experienced an in-flight loss of aircraft control during cruise flight. The pilot initially reported a turbulence encounter at 9,500 feet, and that he saw damage on the upper surface of both wings. He did not recall a significant loss of altitude or loss of control. Data downloaded from the flight displays after the event indicated that the airplane actually climbed to 15,400 feet above mean sea level (msl), nearly 17,500 feet density altitude, which was the maximum operating altitude for the airplane. The airplane then slowed, stalled, and began a rapid descent, losing 13,000 feet of altitude in about 40 seconds before recovering. During recovery, the airplane had an average of more than 4 Gs vertical loading for more than 20 seconds. Such loading would likely have resulted in G-induced loss of consciousness (G-LOC) or near-loss of consciousness. The pilot's apparent failure to accurately recall the events of the flight is likely a result of the confusion associated with hypoxia, and the subsequent confusion and amnesia associated with G-LOC or near G-LOC. It is unclear exactly why the pilot chose to increase his altitude beyond 12,500 feet msl, above which oxygen use would have been required after 30 minutes. Regardless, he continued to climb the airplane above 14,000 feet msl, an altitude above which oxygen use would have been required by the pilot regardless of the time spent at that altitude, and he subsequently climbed to above 15,000 feet, at which point oxygen use would have been required by all occupants. The pilot confirmed that neither he nor his passengers used supplemental oxygen during the flight. Examination of the airplane found no evidence of mechanical failure or malfunctions that would have prevented the airplane from operating normally.

Verbatim NTSB analysis and probable cause from the NTSB dataset