The National Transportation Safety Board today released its preliminary report on the fiery helicopter crash in a residential neighborhood of Kailua in late April.

The report lists details of NTSB’s findings during its on-site investigation but does not list a cause. That final report, including a probable cause, typically takes between 12 to 24 months, said spokesman Eric Weiss.

According to the report, at about 9:10 a.m. on April 29, a Robinson R44 with the registration number N808NV hit the terrain in a residential neighborhood while maneuvering near Kailua. The commercial pilot and two passengers were fatally injured, and the helicopter destroyed.

“Witnesses reported that they heard the helicopter overhead but didn’t look until they heard an odd noise followed by a loud metallic bang,” said the report. “They subsequently observed the helicopter in a nose low attitude descending rapidly; none of the rotor blades were moving and the helicopter appeared to be descending vertically with little forward motion. Witnesses reported observing pieces falling from the helicopter which included: a piece of the main rotor blade, plexiglass, pieces of airframe, and a fuel tank. The helicopter impacted the street and a post-crash fire ensued.”

The male pilot has been identified by the Honolulu Medical Examiner’s office as Joseph G. Berridge, 28, of Honolulu, and the two female passengers as Ryan McAuliffe, 28, of Chicago, Ill., and Jan Burgess, 76, of Australia.

Additional findings from the report include:

>> The helicopter was registered to United Helicopter Leasing, LLC and operated by Novictor Aviation LLC, which offers air tours as Novictor Helicopters.

>> The flight left from Daniel K. Inouye International Airport in Honolulu at about 8:54 a.m. in good weather conditions, and a Visual Flight Rule (flight by sight, without instruments) plan was opened.

>> At 8:57 a.m., the automated weather observation at Kaneohe Bay Marine Corps Air Station about three miles north of the accident site indicated wind at 8 knots, visibility at 4 miles and broken clouds at 1,800 and 2,800 feet above ground level, light rain and a temperature of 75.2 degrees Fahrenheit.

>> The helicopter was destroyed and there was an on-ground fire, but no aircraft explosion, resulting in three fatalities.

The report was released within days after U.S. Sen. Mazie Hirono sent letters to heads of the NTSB and FAA, demanding more information about the accident in Kailua, as well as all air tour accidents and unintended landings in Hawaii over the past five years, as well as a detailed history of problems associated with the Robinson R44 helicopters.

Samantha Link was the NTSB’s investigator in charge, with participation from Joe Monfort of the Federal Aviation Administration in Honolulu; Thom Webster of Robinson Helicopters in Torrance, Calif.; Troy Helgenson of Lycoming Engines from Williamsport, Pa.; Nicole Vandelaar of Novictor Aviation in Honolulu and Spencer Leonard of the FAA in Honolulu.

On the evening of April 30, crews removed the helicopter wreckage from Oneawa Street with a crane and flatbed truck. According to the NTSB, the helicopter wreckage has been moved to a secure location for further examination.