WPR18LA010 · Robinson Helicopter R44 UNDESIGNAT

During a night instructional flight in the helicopter, the commercial pilot receiving instruction and the flight instructor departed and flew uneventfully to an adjacent island, where they conducted a practice instrument approach to an airport before they initiated the published missed approach procedure. As the flight reestablished radio communication with air traffic control, the pilots obtained an instrument flight rules clearance for their return to the departure airport. Radar and radio contact with the helicopter were lost shortly thereafter. Air units from the United States Coast Guard and a local fire department located some floating debris in the ocean the night of the accident and the day following the accident, respectively. The wreckage was located about 12 months following the accident submerged in the Pacific Ocean at a reported depth of 298 ft. A portion of the located wreckage was recovered about 3 months later. A postaccident examination of the recovered wreckage revealed no evidence of any preexisting mechanical malfunctions that would have precluded normal operation of the airframe or engine.

Weather radar depicted an area of moderate-to-heavy rain showers along the helicopter's flight path about the time radar and radio contact were lost. Although the pilots had access to sufficient weather information to properly plan their flight around the weather and could have asked for further assistance in avoiding the weather from air traffic control, they elected to fly into an environment favorable to unexpected changes in wind direction and speed due to heavy rain showers, which could result in localized instrument meteorological conditions; however, because only a portion of the wreckage was recovered, the reason for the helicopter's sudden descent and impact with open ocean waters could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset