The civilian pilot of the tour helicopter that crashed off the USS Arizona Memorial visitor center a week ago told a federal accident investigator that he felt “a vibration” followed by a grinding noise, then “a loud bang” before he was forced to ditch his aircraft into Pearl Harbor, fatally injuring one of four passengers on board, according to a preliminary report by the National Transportation Safety Board.

The preliminary report, released Wednesday, said pilot Ryan Rohner had planned to make an emergency landing on shore, but veered away at the last moment to avoid hitting a crowd of people.

Riley Dobson, 16, of Ontario, Canada, died from injuries he suffered in the crash of the Bell 206B JetRanger, according to the city Medical Examiner’s Office. An autopsy will be conducted to determine the cause of death.

Rescuers said they had to cut the seat belt strapping the teenager into his seat before they could free him from the submerged helicopter.

Dobson was an equestrian who competed in several horse shows throughout Ontario. He was a high school student at Centennial Collegiate Vocational Institute in Guelph, according to the Waterloo Region Record, an Ontario newspaper. In honor of the teen, flags flew at half-staff outside his high school this week.

TWO family members, a 50-year-old man and 45-year-old woman, remain in stable condition at Pali Momi Medical Center. Another family member was treated at a hospital and released Feb. 18.

Rohner, who has been a pilot with the Hawaii Army National Guard since 1999, was flying the single-engine helicopter owned by tour company Genesis Helicopters when it crashed at about 10:30 a.m. Feb. 18.

Rohner told an NTSB investigator that while in flight over Ford Island, he felt a vibration followed by a grinding noise.

“Shortly after, the pilot heard a loud bang, scanned the instrument panel and saw that the engine instruments indicated the engine was still running, however, rotor rpm decreasing,” the report said. “The pilot initiated an auto rotation to a grassy area near Contemplation Circle at the World War II Valor in the Pacific National Monument. As the pilot neared his intended landing area, he observed multiple people within the area. The pilot stated he initiated a left pedal turn, attempting to land close to the shoreline. Subsequently, the helicopter descended rapidly into the water, about 20 feet from the shoreline.”

TALKING with an air traffic controller seconds before the crash, Rohner said he was heading toward the south ramp at Ford Island. An air traffic controller then asked the pilot to head instead toward the federal prison and hold in place for further direction.

Rohner acknowledged the request. Twenty-two seconds later, Rohner issued a distress call: “Tower. Chopper 8. I think I’m going down.”

On Wednesday, Rohner, a UH-60 Black Hawk helicopter pilot, remained hospitalized at Tripler Army Medical Center.

The helicopter, submerged in about 40 feet of water, was recovered the day after the accident and rinsed with fresh water. The wreckage was moved to a hangar at Honolulu Airport operated by Genesis Helicopters for further examination.