What happened
A newly acquired piston-powered helicopter was recently delivered to Saipan via ship, transported inside a container. Following the unloading process, a crew consisting of the pilot, a mechanic, and a mechanic's helper reassembled the aircraft on the dock.
To facilitate the flight from the dock to the company's base at the airport, the mechanic's helper was dispatched to a fuel facility. He purchased 10 gallons of Jet-A fuel, which was then used to service the aircraft.
After the fueling was complete, the pilot started the engine and performed a run-up. The aircraft departed for a three-mile flight toward the airport. During the flight, the engine lost power, forcing the pilot to perform an autorotation. The aircraft subsequently landed on a submerged reef in approximately 3 to 4 feet of water. There were no injuries reported.