(BCN)—Two people died in a single-engine plane crash in the hills near Concord last week, not one person as originally reported, according to a preliminary report by the National Transportation Safety Board.

Federal Aviation Administration officials originally reported that the Oct. 25 crash killed just the pilot of the Beechcraft A36 Bonanza, but the NTSB’s preliminary report says that in addition to the pilot, a certified flight instructor was also killed.

The Contra Costa County coroner’s office would not confirm the number of people killed in the crash, nor would the FAA. The identities of the people who died have not been released.

The NTSB report does not give a cause for the crash but describes the final moments of the flight, which hit the ground at about 12:30 p.m., shortly after taking off from Concord’s Buchanan Field Airport.

After taking off, the plane made a left turn and climbed “in a relatively straight track to the east, with a climb rate of about 800 feet per minute,” the report says.

After about three-and-a-half minutes in the air, the plane reached an altitude of roughly 3,600 feet, then took a roughly 20 degree turn to the left and started “a steep descent,” dropping at about 5,000 feet per minute.

The Beechcraft then struck two high-tension power lines before striking the ground about 300 feet away, near Nortonville Road.

Crews found about 25 broken pieces of the plane leading to the crash site, but a fire destroyed most of the rest of the aircraft, according to the report. No communications were captured from the plane after takeoff.

The report also states that the plane had recently been installed with new navigation equipment, and the purpose for the fatal flight was to help the pilot become familiar with the new devices.

It was the second flight with the new equipment, according to the NTSB. The first was when a flight instructor flew the plane back from Jackson in Amador County, where the equipment was installed.

The plane’s owner is listed by the FAA as Accretion LLC, a company in Portland, Oregon.