What we know about the fiery NJ plane crash that killed 2

— -- Investigators from the National Transportation Safety Board will spend Tuesday gathering facts about Monday afternoon's fiery crash of a Learjet just outside New Jersey's Teterboro Airport, killing both people on board.

The cause of the crash is unclear, although some details have begun to surface.

The plane departed Philadelphia International Airport at 3:04 p.m. Monday before crashing at 3:30 p.m. just a quarter of a mile from Teterboro Airport while on final approach, according to transportation authorities and data from FlightAware.com.

The jet crashed into three buildings, causing fire damage at two of them, police said. Thirteen cars were also damaged.

No one on the ground was hurt.

Fire and large plumes of black smoke were seen at the crash site.

One witness told ABC News, "It skidded after it hit the top of a building and then skidded into the building adjacent to it, blowing up cars and anything in its path."

Air traffic control audio suggests the flight was progressing smoothly until just before the crash. It appears that no mayday call was placed. Then, just 37 seconds after the pilot's last recorded communication with air traffic control, another pilot informed the tower, "A Learjet just crashed."

At the time of the crash, weather reports in the area indicated winds of 17 mph, with gusts up to 36 mph, a temperature of 66 degrees and 10 miles of visibility. Scattered clouds were reported at 4,500 feet.

While the plane, a Learjet 35 equipped with two jet engines, is certified to hold up to 10 people, local authorities said only two were on board, presumably the pilot and co-pilot. They have not yet been identified.