On October 22, 2018, about 1710 Hawaiian standard time, a Robinson R44 helicopter, N4132H, was substantially damaged when it was involved in an accident near Kaneohe, Hawaii. The pilot and two passengers were seriously injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 air tour flight. The pilot reported that, about 20 minutes into the flight, he felt himself lose consciousness; moments later, he regained consciousness and control of the helicopter. The pilot turned inland and prepared for a precautionary landing. Seconds later, he lost consciousness again, and was awakened by first responders following the accident. The pilot did not recall the descent or impact, and he remembered that, “before everything went black,” he was in a “dream-like state” during which he was piloting a helicopter and knew he was in an emergency situation, but the nature of the emergency was not clear. The passengers stated in an interview, that they remember the pilot slumping over during the flight, and the front seat passenger grabbing the controls to slow the descent before impacting the sandbar. The helicopter landed on a sandbar in about 2 ft of water and came to rest on its left side. The main rotor mast was bent forward, both skids exhibited impact damage, and the tailboom was bent to one side. The wreckage was relocated the next day to a secured location for examination. The pilot began working for the operator in May 2018 and had not reported any medical problems during that time. The pilot possessed a current second-class Federal Aviation Administration (FAA) airman medical certificate with no restrictions. FAA medical records indicated that, in 2012, during an aviation medical examination, an asymptomatic heart murmur was detected. In the same year, the pilot reported having a history of mitral valve replacement surgery. In 2013, the pilot received a special issuance medical certificate that required providing periodic cardiovascular evaluations to the FAA. His cardiologist reported that his valve was in good condition and had placed no restrictions on the pilot’s activities. During the hospital stay following the accident, the pilot had episodes of complete heart block, which required placement of a permanent pacemaker.