A camera outside of the Bagram Air Field in Afghanistan caught footage of Monday's horrific crash of a civilian cargo plane, which left seven people dead.

The plane, a contractor-operated Boeing 747-400 carrying vehicles and other cargo, does not appear to be under any attack in the video. On its ascent, it's shown pitching at a terrifying angle before unexpectedly – and terrifyingly – crashing outside the massive airbase, a major logistical hub for the U.S.' longest war.

Pentagon officials today huddled around computers in the public-affairs office to watch the video, which appeared on YouTube and LiveLeak, while covering their mouths in astonishment and horror. The military command in Afghanistan is "looking into the authenticity of the video," according to Navy Cmdr. Bill Speaks.

No cause of the crash has been determined yet. No missile or any other object is shown in the video approaching the 747-400. A takeoff stall is something all pilots train for regularly, especially commercial pilots, so it's highly unlikely the accident is a result of pilot error.

The contractors responsible for the aircraft, National Air Cargo, put the time of the incident at 7 a.m. Eastern yesterday, which would be around 3:30 p.m. Bagram local time. The plane was heading for Dubai in the United Arab Emirates, carrying unspecified vehicles and other cargo. "None of the crew members survived," a statement from National Air Cargo reads. "This was a purely cargo flight and no passengers were aboard."

Some early reports are saying the crew mentioned the cargo had shifted. That's a much more likely reason for the stall than pilot error. A mechanical problem with the flight controls, in particular the elevator trim known as a "runaway trim" is another, though less likely scenario.

Any airplane must be carefully loaded to maintain the center of gravity within a carefully designed and tested zone of the airplane. Cargo aircraft are always loaded so light things are far away from the "CG" and heavier things are closer to the CG. If the cargo inside the 747 were to break loose during take off, it would slide towards the tail, dramatically shifting the center of gravity to the back of the airplane. This would cause the nose to rise dramatically, and without sufficient power to overcome the extremely high angle of attack (the angle between the wing and the flow of air), the air flowing over the wings would "detach" from its normal flow, causing a stall where the wings can no longer generate enough lift to keep the airplane airborne.

It does not appear from the video that anyone on the ground was injured, although the plane crashes near trucks on the base's perimeter. Whomever shot the video – and it seems shot from a security vehicle, and an accent that sounds Australian is audible – does not scream or exclaim as the plane crashes. The video is eerily quiet; at one point, something sounding like a dog whines.

"National will release additional information as it becomes available, in cooperation with government authorities," the company states. "Our focus at this time is on the family members of those we've lost, and on assisting the NTSB [National Transportation Safety Board] and Afghanistan Civil Aviation Authority in their investigations. As of now, the cause of the accident is unknown."

Normally if a pilot encounters a stall, they must push forward on the control stick or yoke to reduce the angle of attack and allow the wings to begin generating lift again. Though if the cargo was in the back of the airplane, it was probably not possible to counteract the severely out of balance airplane. This kind of accident does happen, though is less common on large aircraft where more attention is usually paid to how securely the cargo is attached. Similar crashes have happened with skydiving aircraft where the skydivers somehow fall to the back of an airplane on takeoff.

Once the wings stall, any sideways, or yaw motion can cause an airplane to enter a spin. A spin is recoverable if you have enough altitude, but the classic stall/spin on takeoff or landing usually doesn't allow for enough time to recover.

Video in the past has captured insurgent attacks on U.S. forces in Afghanistan, as well as U.S. firefights and even troops getting blown up by improvised explosive devices. Pentagon officials were unaware of earlier videos of civilian cargo planes crashing.