The NTSB is investigating a small plane crash in Atlanta Friday that killed four people and shut down a busy interstate, snarling traffic for hours.

A Piper PA-32 ran into trouble just after taking off from DeKalb Peachtree Airport shortly after 10 a.m., officials said. The plane crashed on I-285 and burst into flames.

The victims were identified as pilot Grady "Greg" Byrd, two of his sons Phillip Byrd and Christopher Byrd, and Jackelyn Kulzer, according to MyFoxAtlanta

Greg Byrd was a reserve deputy with the Buncombe County Sheriff's Office in North Carolina.

“At this time we don’t know the cause of the accident,” NTSB investigator Eric Alleyne told reporters.

Alleyne said investigators will reconstruct the plane to determine the cause of the crash. He said a report on the crash may take between six months and a year.

The air crash expert said it’s unclear if the pilot made any emergency calls after taking off.

Witnesses told Fox 5 they heard a loud boom and then saw a “fireball.”

“Came over the top of my truck, hit the median and just exploded,” Blake Green said.

Motorist Don McGhee, 48, watched the aircraft nearly hit a traffic light pole near the highway on ramp.

"It looked like it was struggling. You could see him trying to get the nose of the plane up. It was edging up, and then it just dropped," McGhee said. "It was just a huge fire, just smoke and fire."

"It's a miracle, literally a miracle, that no other cars were hit," DeKalb Fire Capt. Eric Jackson told reporters.

The plane crashed into the highway median. Video showed debris from the plane littering the roadway, including a propeller.

Click here for more from MyFoxAtlanta.