Updated

Authorities say they have not yet recovered the black boxes to determine why a UPS jumbo cargo plane crashed early Wednesday morning just outside a Birmingham, Ala., airport, killing the two pilots.

NTSB member Robert L. Sumwalt said at a news conference Wednesday that because the tail of the aircraft is still smoldering, investigators haven't been able to gain access yet to the cockpit-voice and flight-data recorders, but that investigators will be on the scene for a number of days.

Sumwalt says a preliminary investigation of the crash indicates the pilot and co-pilot did not make any distress calls prior to impact.

A UPS spokesman confirmed to MyFoxAL.com that the plane was a UPS A-300 Airbus, tail number N155UP, with two crew members aboard. The flight originated in Louisville, Ky., and crashed upon its approach to Birmingham-Shuttlesworth International Airport before dawn.

The plane crashed in an isolated field outside the airport's perimeter fence and a white plume of smoke was seen rising from the site. Teams of emergency crews responded to the crash.

More On This...

    The UPS said it is in the process of notifying the shippers of all the packages aboard the flight.

    Sharon Wilson, who lives near the airport, said she was in bed before dawn when she heard what sounded like engines sputtering as the plane went over her house.

    "It sounded like an airplane had given out of fuel. We thought it was trying to make it to the airport. But a few minutes later we heard a loud `boom,"' she said.

    Another resident, Jerome Sanders, lives directly across from the runway. He said he heard a plane just before dawn and could see flames seconds before it crashed.

    "It was on fire before it hit," Sanders said.

    The National Transportation Safety Board deployed a Go-Team from Washington, D.C., to investigate the crash. The scene is about a half-mile north of Runway 18 where weather conditions were rainy with low clouds.

    "The plane is in several sections," said Birmingham Mayor William Bell, who was briefed on the situation by the city's fire chief. "There were two to three small explosions, but we think that was related to the aviation fuel."

    Previously, a UPS cargo plane crashed on Sept. 3, 2010, in the United Arab Emirates, just outside Dubai. Both pilots were killed. Authorities there blamed the crash on its load of between 80,000 to 90,000 lithium batteries, which are sensitive to temperature. Investigators found that a fire on board likely began in the cargo containing the batteries.

    The Associated Press contributed to this report