[1] The National Transportation Safety Board (NTSB) attributed the accident to hydroplaning caused by heavy rainfall on the ungrooved runway; although the pilots were found to have made a series of errors during final approach and landing, the NTSB concluded that these errors had little effect on the final outcome, as the aircraft would have been unable to stop even if the landing had been executed properly.

[9][11] The accident was investigated by the National Transportation Safety Board (NTSB), Boeing, and the United States Navy.

[5][12][13] Initial causes of the investigation focused on a possible failure of the thrust reverser and the pilot's request to change runways.

[15] The recorded weather conditions at 9:22 PM included heavy rain and thunderstorms with wind from 350° at 4 kn (7.4 km/h; 4.6 mph).

[15] A week after the accident, the aircraft was lifted onto a barge and floated up the St. Johns River and moved to shore at Reynolds Industrial Park in Green Cove Springs.

[15] On August 4, 2021, the NTSB published its final report, attributing the accident to a lack of runway grooving, which caused hydroplaning on touchdown and poor braking.

[2] This was aggravated by the airline's inadequate runway evaluation guidelines, the flight crew's failure to abort the approach (which was unstabilized due to the captain's heavy workload), excessive airspeed on touchdown, the first officer's limited experience in heavy jets like the 737, and the pilots' failure to promptly deploy the speed brakes; however, the NTSB concluded that even if these errors had not occurred, the aircraft would still have been unable to stop under the prevailing conditions.

[2][9][17] This article incorporates public domain material from websites or documents of the National Transportation Safety Board.