Witnesses told investigators with the federal agency that they saw the helicopter in level flight before it began descending nose down toward the Bayview Terrace community on Jan. 30, the report states.
The four-seat Robinson R44 was heading to Catalina Island before it clipped the roofs of two houses and hit the side of a home on Shearwater Place near Egret Court, according to the report.
The document does not identify what caused the helicopter to crash.
The R44 was leased to Revolution Aviation, a flight school and touring company at John Wayne Airport, from Spitzer Helicopter LLC of Canyon Lake in Riverside County, according to public records.
The crash killed Joseph Anthony Tena, 60, a Newport Beach businessman, and Kimberly Lynne Watzman, 45, of Santa Monica and Brian Reichelt, 56, of Hollywood, Fla., both of whom worked for the Standard hotel chain.
Two other people — a passenger in the copter and a pedestrian on the ground — were injured, authorities said.
Authorities have not specified who was piloting the copter. Tena was the only person identified in the crash who had a pilot's license, according to Federal Aviation Administration records.
The NTSB's full report on the crash could take up to a year.