What happened
The Sikorsky S-43 was on approach to Fort-de-France, Martinique, after turning west from a radio beacon position. The crew initiated a descent in wide spirals over open water. Although earlier weather reports indicated acceptable conditions with a ceiling of 2,000 feet and visibility of 2 miles, the pilot encountered significantly deteriorated conditions during the let-down. Visibility dropped to approximately half a mile due to heavy rain squalls, and the wind direction shifted from east-southeast to southwest.
The pilot observed that the left engine had cut out momentarily earlier in the flight and was concerned about single-engine performance. With weather closing in rapidly, the decision was made to attempt an emergency landing. The aircraft approached a seldom-used section of the harbor with full flaps deployed. Intense rain obscured forward vision through the windshield, forcing the pilot to use a side window to judge the water surface. The plane landed on the crest of a 4 to 6-foot swell.
Upon water contact, the pilot attempted an immediate takeoff due to the size of the swells, but the left engine failed to respond. The bow submerged, causing the aircraft to yaw right and shear off the left wing float. This led to the left wing submerging and the aircraft rolling onto its back, rapidly filling with water. Crew members rescued all but four of the ten passengers from the sinking hull, which went under within ten minutes of the initial contact.
Findings
The investigation concluded that the accident resulted from the pilot's decision to land in conditions where the water surface was unsuitable for a flying boat. The combination of heavy rain, reduced visibility, and significant ground swells created an environment incompatible with safe landing operations for this type of aircraft.