Two children and two adults were killed Friday afternoon when a small aircraft crashed and burst into flames at DeKalb-Peachtree Airport, the DeKalb medical examiner’s office confirmed Monday.

Jonathan Rosen, 47, the plane’s pilot and owner, died in the crash, as did his 14-year-old daughter Allison. Lauren Harrington, 42, and Julia Smith, 13, were also on the plane, according to the medical examiner’s office. There were no survivors.

Daniel Boggs, air safety investigator for the National Transportation Safety Board who is leading the probe of the crash, said Sunday that he believed the passengers were on a personal family trip to Houston.

NTSB was on the ground at DeKalb-Peachtree over the weekend investigating the cause of the crash, interviewing witnesses and air traffic control tower workers and collecting videos. Officials from the independent agency, which is tasked with probing every civil aviation accident in the country and issuing safety recommendations, will likely be on site for two or three more days, Boggs said Sunday.

“We’ll be looking at the weight of the aircraft. We’ll be looking at the engine,” he said. “We’ll be looking at the servicing. We’ll be looking at the qualifications of the pilot.”

Later Sunday, a salvaging company was expected to move the remains of the aircraft to a secure facility, where NTSB officials will dissect the surviving components of the plane. It will be particularly difficult because the fire damage was so extensive, Boggs said.

Unlike larger and commercial aircraft, small personal planes don’t have black boxes or cockpit voice recorders that can shed light on the cause of crashes. Some smaller planes do feature boxes that show how the aircraft’s engines were running.

“We’re going to look at that but there’s so much fire damage we don’t think we’re going to get any usable data off of that,” Boggs said.

The 1978, six-seater Cessna P210N Centurion aircraft crashed at about 1:10 p.m. Friday. Cellphone video appeared to show the crash near the runway seconds after takeoff and a large plume of black smoke ascending from the plane’s charred remains.

Boggs said the aircraft was recently modified from a Continental engine to a Rolls Royce turbine engine. The plane was outfitted with an additional tank that was full of fuel, which explains the intensity of the fire, he added. NTSB is waiting for additional paperwork about the modification.

Boggs said he did not believe the weather was a factor in the crash.

NTSB plans to issue a preliminary report in 14 days, according to Boggs. A final assessment will be published in 12 to 18 months.

Rosen was CEO of Entaire Global Companies and founded a family foundation that teaches financial literacy skills to teenagers. His daughter was an eighth-grader at Peachtree Middle School who enjoyed rock climbing and weightlifting, according to her obituary. More information about Harrington and Smith was not immediately available.

Located in northeastern DeKalb less than 10 miles from downtown Atlanta, DeKalb-Peachtree Airport is the state’s second busiest behind Hartsfield-Jackson, with roughly 209,000 annual takeoffs and landings.

The airport and DeKalb County government issued a joint statement Monday thanking first responders and expressing condolences to the families who lost their loved ones in the crash. The statement was also read at an airport advisory board meeting Monday afternoon. Airport Director Mario Evans declined to discuss the crash further pending findings from the investigation.