A 57-year-old tour helicopter pilot suffered an undisclosed medical condition at the time of Monday afternoon’s accident at the Kaneohe Bay sandbar, the tour company said.

“We have confirmed that the pilot suffered a medical condition in flight,” said Nicole Vandelaar, owner and chief pilot of Novictor Helicopters.

The male pilot and two passengers, who are visitors to Hawaii, were taken to the Queen’s Medical Center in serious condition, but have been upgraded to stable condition.

Vandelaar declined to elaborate on the pilot’s medical condition out of respect for his privacy. She noted that the pilot’s injuries, as well as the passengers’ injuries, are non-life-threatening. “I’m just grateful that everybody is OK.”

Allen Kenitzer, spokesman of the Federal Aviation Administration, said the agency and the National Transportation Safety Board will investigate the accident which happened at about 5:12 p.m.

Crews from the Honolulu Fire Department, Coast Guard, Federal Fire Department and Waterfront Operations of Marine Corps Base Hawaii responded to the downed Robinson R44 helicopter.

HFD spokesman Capt. Scot Seguirant said good Samaritans, including fishermen and two kayakers, assisted the pilot and two passengers who were conscious and alert.

HFD coordinated with federal firefighters and the Marines to transport the three people to Heeia Kea Pier where Emergency Medical Services personnel were waiting.

Paramedics treated the pilot who sustained injuries to his back, head and chest and two visitors — a 35-year-old woman who sustained injuries to her chest, back and left leg and a 31-year-old man who sustained injuries to his head, chest, back and right arm.

Dustin Malama, spokesman of the Honolulu Emergency Services Department, said the pilot and passengers also suffered multiple lacerations to their bodies.