A pilot and three passengers walked away from a helicopter that lost power and crashed Tuesday morning in a gully in a remote section of Sacred Falls State Park in Hauula.

The aircraft was described by one of the passengers as being destroyed after landing upside down with both its main rotor and its tail rotor severed from its fuselage.

“When it lands upside down and you lose both of the rotors, it’s just really a miracle, and we’re so thankful that they all basically walked away from it,” said Dan Dennison, spokesman for the state Department of Land and Natural Resources, which had hired the chopper for scientific fieldwork.

One passenger had a bruised arm from the 11:36 a.m. crash, but everyone else apparently was unhurt.

The group — the pilot, a Division of Fish and Wildlife employee and two representatives of the nonprofit Pacific Rim Conservation — hiked down to a clearing and was transported out of the area by a “good Samaritan helicopter,” which dropped them off at the end of Puhuli Street, Honolulu fire spokesman Capt. Scot Seguirant said.

Two men and two women ranging in age from 34 to 42 declined medical treatment, according to Emergency Medical Services.

The four were driven back to Honolulu by a state Division of Conservation and Resources Enforcement officer.

“They’re very lucky. That’s an understatement, for sure,” Dennison said Tuesday afternoon at a news conference in Honolulu.

The chopper had transported the group to conduct Division of Forestry and Wildlife fieldwork in the Kaluanui Natural Area Reserve.

The team deployed noise- activated song meters to record seabird sounds as part of a seabird population study.

After their work was done, the team members were picked up by the helicopter, Dennison said, and it wasn’t long before it lost power and the pilot was forced to put it into auto-rotation, allowing the craft to descend with the rotor blades driven solely by the upward flow of air through the rotor.

The state employee reported that the chopper was close to making it to a clearing with a flat landing zone but ended up crashing into some trees.

“He credits the pilot with extraordinary skill in bringing the aircraft down and avoiding serious injury,” Dennison said.

Dennison added that the crash survivors didn’t want to make any further statements or be interviewed.

Seguirant said six units from the Honolulu Fire Department, including the Air 1 helicopter, responded to the incident, and the department set up a command post near the Sacred Falls International Meditation Center in Hauula.

Federal Aviation Administration spokesman Ian Gregor identified the aircraft as a Hughes 369E helicopter registered to Kailua-Kona- based K&S Helicopters Inc., which operates Paradise Helicopters with locations across the state.

Oahu Division of Forestry and Wildlife branch manager Marigold Zoll said, “We follow a stringent set of safety protocols, and one of these protocols is known as ‘flight-following,’ which resulted in the incident being reported very quickly. We are thankful everyone walked away from this accident.”

The National Transportation Safety Board is expected to investigate the incident.

Star-Advertiser staff writer Rosemarie Bernardo contributed to this report.