What happened
During a return flight to San Juan, Puerto Rico, following a U.S. Mail delivery, an aircraft experienced a critical power loss shortly after takeoff. The flight was being operated by a crew consisting of a captain and a first officer, with two passengers on board. The aircraft was empty of cargo at the time of the incident. During the initial climb, approximately 10-foot above the ground, the crew initiated the landing gear retraction. At this moment, the RPM of the left engine plummeted from 2,700 to 1,000.
Upon noticing the drop in power, the captain took control of the aircraft from the first officer to manage the emergency. After confirming the failure of the left engine, the crew executed the necessary checklists and feathered the propeller. The crew notified air traffic control of the engine failure and declared their intention to return to the airport. However, the aircraft was unable to maintain its altitude, and the airspeed decreased to approximately 75 knots. Realizing the aircraft could not reach the runway, the captain instructed the passengers to prepare for a ditching by donning life vests.
The captain performed a controlled ditching into the water. Following the impact, all four occupants successfully exited the aircraft via the overhead cockpit escape hatch and reached a life raft. The aircraft remained buoyant for roughly ten minutes before sinking nose-first to the seabed at a depth of approximately 100 feet. The aircraft was not recovered.
Findings
Post-accident underwater imagery provided by the operator revealed that the nose and cockpit sections of the aircraft type had collapsed. Observations of the engines showed that the propeller on the left engine was in the feathered position, while the right engine's propeller remained in a low pitch position. The primary factor in the loss of altitude was the sudden drop in RPM of the left engine during the climb phase.