At about 19:03 eastern time, a Robinson R22 crashed into the Atlantic Ocean about 100 yards offshore of Marathon, leaving the flight instructor and student pilot with minor injuries. The flight had departed Key West at about 15:30 with another helicopter en route to Fort Lauderdale Executive. No weather briefing had been obtained. They entered IMC and the R22 turned toward clear skies in the east while the other helicopter landed. The accident helicopter flew to Indian Key Island and landed to wait out the weather. The CFI got a weather briefing, which told of a line of thunderstorms along the route of flight. The weather improved and the pilot departed the island. He flew toward a highway he planned to follow and again encountered instrument conditions. He reversed his course towards Indian Key Island, lost directional control of the helicopter due to spatial disorientation and the helicopter struck the ocean.