Incident Overview
The commercial pilot of a multiengine airplane was the first of two aircraft to depart on a cross-country flight over the Atlantic Ocean. The pilot of the second airplane stated that both pilots reviewed the weather for the route and the destination before departure, but there was no record of the accident pilot receiving an official weather briefing, and the information they accessed could not be determined.
The second pilot contacted air traffic control after departure and was advised of thunderstorms near the destination; he altered his route and landed uneventfully. He did not hear the accident pilot on the en route frequency.
Weather Conditions
Two inflight weather advisories were issued for the route and destination area about 42 and 15 minutes before the accident flight departed, respectively, warning of heavy to extreme precipitation associated with thunderstorms. It could not be determined whether the accident pilot received these advisories.
A local resident about half a mile from the accident site took photos of the approaching thunderstorm, documenting a shelf cloud and cumulus mammatus clouds along the storm's leading edge—indicators of potential severe turbulence. Weather imagery and the airplane's flight path showed that the airplane entered the leading edge of extreme intensity radar echoes with tops near 48,000 feet. Imagery also depicted heavy to extreme intensity echoes over the accident site extending to the destination airport.
Sequence of Events
Review of air traffic control communications and radar data revealed that, about 5 miles from the destination airport, the pilot reported to the tower controller that he was flying at 700 feet and "coming in below" the thunderstorm. There were no further communications. The airplane's last radar target indicated 532 feet about 2 miles south of the shoreline. The airplane was found in about 50 feet of water, fragmented in several pieces.
Investigation Findings
Postaccident examination revealed no preimpact anomalies with the airplane or engines that would have precluded normal operation. It is likely that the pilot encountered gusting winds, turbulence, restricted visibility in heavy rain, and low cloud ceilings in the vicinity of the accident site and experienced an in-flight loss of control at low altitude. Such conditions are conducive to the development of spatial disorientation; however, the reason for the pilot's loss of control could not be determined based on the available information.
Probable Cause
The probable cause was the pilot's decision to fly under a thunderstorm and a subsequent encounter with turbulence and restricted visibility in heavy rain, which resulted in a loss of control.