WASHINGTON, Dec 6: The aging B-52 bomber was at the centre of controversy on Wednesday after a wayward bomb dropped from one of the bombers killed three US special forces troops and five Afghan allie.

The B-52 “Stratofortress” is a long-range bomber designed with conventional and nuclear warfare in mind and was the backbone of US bombing campaigns in the Vietnam and Gulf wars.

In Afghanistan, the planes — most of which are now older than the pilots who fly them — have been used for the most part to target concentrations of Taliban troops lined up against the opposition Northern Alliance.

The B-52 first entered service in 1955, at the height of the Cold War, and the last production model of the 74-million-dollar aircraft was delivered to the air force in 1962.

During the Vietnam War, the plane was engaged in a sustained campaign of saturation bombing that lasted eight years.

During the Gulf War, the B-52 bomber dropped 40 percent by weight of all the bombs dropped on Iraq and was used to particular effect in carpet bombing runs.

The air force has 85 B-52s in active service.

The B-52 is 48.5 metres in length, with a wingspan of 56.4 metres and a crew of five. Each carries 31,500 kilograms of explosives, including nuclear weapons, to a range of 14,162 kilometres.—AFP