What happened
A cargo flight operated by Fresh Air, Inc. departed from runway 10 at Luis Muñoz Marle International Airport (SJU) in San Juan, Puerto Rico, bound for St. Maarten. Shortly after the departure, the crew declared an emergency. The captain requested a return to the airport and inquired if air traffic controllers could observe smoke trailing from the aircraft. While controllers did not observe unusual smoke, they cleared the aircraft to land on runway 28.
As the aircraft attempted to align with the new runway, it entered a descending right-hand turn at an altitude of approximately 520 feet. During this maneuver, the aircraft's airspeed dropped to 88 knots, which was below the published stall speed for level flight. The aircraft continued to bank to the right until it struck Laguna La Torrecilla, about one mile east of the departure end of the runway. The impact destroyed the aircraft and caused the deaths of two pilots.
Findings
Post-accident inspections of the wreckage revealed thermal damage to the right wing's rear spar and the area near the engine's exhaust muffler assembly. While an exact ignition source was not identified, the damage was located aft of the engine. Investigators found no evidence of mechanical failures that would have prevented the engines from operating normally.
Data indicates the aircraft was operating near its stall and controllability limits during the final moments of flight. Although the crew likely intended to shut down the right engine and feather its propeller to manage the emergency, physical evidence showed the left propeller had been feathered, while the right engine settings were consistent with a shutdown. The investigation could not determine the specific sequence of engine management actions taken by the crew.