Known as the northbound Island Run, Flight 216 departed the airport at Port of Spain at 08:04 with Fort de France the first scheduled stop. Preparations for the flight included briefing of the pilot on weather conditions to be expected, forecasts for which indicated squally weather lingering over most of the route in the rear of a receding tropical storm. About 10 miles west of Martinique the plane entered an area clear of clouds and descent was started in wide spiral over the open sea. The co-pilot then established radio communications with the company’s base station and at 09:55 was advised that landing conditions at Fort de France were: wind ESE 20 knots, visibility 2 miles, ceiling 2,000 feet, barometer 1012.2, sea moderate with ground swells. During the let-down to Fort de France the pilot observed that the clouds extended upwards from 800 feet and that very heavy rain underneath the overcast made it impossible to determine accurately the condition of the water surface. During the let-down the left engine cut out momentarily and then resumed normal operation. Instead of encountering the weather conditions reported at 0955, the pilot found that low ceiling and heavy rain squalls prevailed with visibility reduced to about half a mile. Proceeding to Fort de France under the overcast, the captain circled the company station at an altitude of 500 feet and noted that the wind-sock indicated a southwest surface wind instead of the previously reported east-southeast wind. Remarking to the co-pilot that he was afraid they would “lose” the left engine and, being apprehensive of single-engine performance of the Sikorsky S-43, the pilot elected to risk a landing under his emergency authority. At this moment the company radio advised that the weather was closing in rapidly and a landing should be made as soon as possible. Heading into the southwest wind an approach with full flaps was made toward a portion of Fort de France harbor seldom used for landing. During the latter part of the approach intense rain precluded forward vision through the windshield and only by opening a side window in the cockpit was the captain able to see the surface of the water just before the plane landed on the crest of a 4 to 6-foot swell. On contact with the water and alarmed by the size of the surface swells, the pilot attempted to take off, using full throttles, but the left engine failed to respond. The bow submerged and the plane yawed to the right, shearing off the left wing float and permitting that wing to submerge. As the left wing went down the aircraft rolled over on its back, rapidly filling with water. The plane sank within 10 minutes. PROBABLE CAUSE: “The attempt by the pilot to land the aircraft in conditions of water surface not suitable for landing of a flying boat.”