Grumman American Avn. Corp. AA 5B N28718 accident near Florence, Oregon

Probable cause

The noninstrument-rated pilot’s visual flight into instrument meteorological conditions, which resulted in his spatial disorientation and the subsequent loss of airplane control.

NTSB analysis

A witness reported observing the noninstrument-rated private pilot departing the airport in marginal visual meteorological conditions; the pilot was conducting a personal flight. The witness further reported that, about 1 hour later, he could hear airplane engine noise approaching the airport but that he could not see the airplane due to low ceilings and visibility. The witness also noted that the weather conditions were quickly deteriorating. Another witness reported that, while he was walking along the beach, he heard airplane engine noise in the low clouds, which he estimated were about 100 ft above ground level (agl). This witness reported that a small airplane then emerged from the clouds above the river traveling westbound away from the airport and that the airplane then "pitched up and reentered the cloud[s]." Shortly after, he saw the airplane exit the low clouds about 400 yards offshore in a near-vertical attitude with the right wing low before it impacted the ocean. No radar data depicting the accident flight were available. A majority of the airplane was not located in the ocean; therefore, postaccident airframe and engine examinations could not be conducted.

An automatic weather observation system located 2 1/2 miles from the accident site reported overcast clouds at 300 ft agl and visibility of 1 1/4 miles around the time of the accident. Witnesses estimated that the actual ceiling and visibility were lower near the accident site. In addition, a band of low stratiform-type clouds was present over the coast and the accident site. The low cloud ceiling and restricted visibility conditions would have been conducive to the development of spatial disorientation as the noninstrument-rated pilot maneuvered in the low-visibility conditions. The airplane's rapid descent from the clouds was consistent with the pilot's flight into instrument meteorological conditions and subsequent loss of airplane control due to spatial disorientation.

Postaccident toxicology testing detected 6-ß-natrexol, the primary metabolite of naltrexone, in the pilot's blood and liver. Naltrexone alone is not known to be generally impairing, but early in treatment, its use can precipitate symptoms of withdrawal. Without more information about the underlying condition that led to the pilot's use of naltrexone, it could not be determined whether or not the condition contributed to the accident.

Text from the NTSB. Open the NTSB docket for WPR14FA244 for the full record.