The most powerful conventional bomb in the US arsenal exploded in a huge, fiery cloud on a Florida test range on Friday after being dropped by an Air Force cargo plane in the last developmental step for the nearly 11-tonne "mother of all bombs."
An MC-130E Combat Talon I dropped the 9,800kg satellite-guided GBU-43/B Massive Ordnance Air Blast Bomb, or MOAB, over the test range at Eglin Air Force Base in northwestern Florida, said base spokesman Jake Swinson.
A plume of smoke rose more than 3km in the air and was visible 65km away in Pensacola, Florida.
"It looked like a big mushroom cloud filled with flames as it grew and grew and grew," Swinson said after the afternoon test.
"It was one of the most awesome spectacles I've seen," he said.
The Air Force called the test successful, saying the bomb separated cleanly from the aircraft with the help of a parachute at an altitude of 6,248m, glided 41 seconds to its target area and detonated as planned.
Officials said the bomb was developed in only nine weeks to be available for use this spring in the Iraq war, but commanders opted not to use it. Its only previous live test was on March 11, the week before the US-led invasion.
The MOAB, the most powerful non-nuclear US bomb, carries 8,482 kg of high explosives, detonating just above the ground when the tip of the 9.1m-long bomb hits the earth, Swinson said.
Swinson said the bomb was now available to US commanders, but said there were no immediate plans for it to go into production.
The US has had larger conventional bombs in the past but none in the current US arsenal is as big.
The MOAB is envisioned as a successor to BLU-82, the 6,800kg "Daisy Cutter."
The "Daisy Cutter" was used to clear helicopter landing areas in the Vietnam War and was used in the 1991 Gulf War and in 2001 in Afghanistan. In the latter two conflicts, US commanders used the "Daisy Cutter" partly for the psychological effect of such a massive blast.
Swinson said it was the last of four developmental tests for the MOAB -- nicknamed the "mother of all bombs" by some in the military. The two live tests were preceded by two inert tests.
Lynda Rutledge, MOAB program manager at Eglin, said there were minor modifications to the MOAB tested on Friday compared to the one detonated in March, adding that the latest test sought to give commanders a chance to understand how the big bomb performs, particularly relating to targeting.