Profile: AC-130 gunship

Special operator: The AC-130U has sophisticated weapons control

The AC-130 Spectre gunship which the Americans are using for special operations in southern Afghanistan was designed for close support of ground forces.

It is a development of the C-130 Hercules transport aircraft and as such is slow, flying at less than 300mph, but has a range of at least 1,500 miles without needing to refuel and can loiter over a combat area for some time.

The AC-130s are operated by the US Air Force's special operations group, based at Hurlburt Field, Florida.

They have several big guns projecting from the left side of the fuselage: either two 40mm cannons or a 25mm Gatling gun that can fire up to 1,800 rounds per minute, depending on the version, and 40mm and 105mm cannons.

Computerised

Although based on an old Hercules transport plane, the AC-130 has one of the most complex aircraft weapon systems.

It uses television, infra-red and radar sensors to locate ground targets, even at night. Uniquely, in the latest type, the targeting computers can follow two separate targets with two different sensors and fire two different guns.

Former crew members say that, in practice, the guns were never fired simultaneously - and the ammunition load was an issue, so it was used sparingly.

The newest AC-130U version - known as Spooky II - has twice the ammunition capacity.

Large crew

The aircraft has more than a dozen crew: Pilot, co-pilot, navigator, fire control officer, electronic warfare officer, flight engineer, operators for its TV camera and infra-red detection set, a loadmaster, and four or five "gunners" - who reload the weapons which are normally controlled from the flight deck.

Although regarded as a highly successful machine - used most recently in support of operations in Panama, Grenada, the Gulf War and Bosnia - its slowness and typical low operating altitude make it vulnerable to ground fire.

It does have a system that drops chaff and flares to counter radar and infra-red guided missiles. There are also heat shields under the engines to try to mask them from heat-seeking missiles.

Even so, one AC-130 was shot down in Iraq by a surface-to-air missile. The other recent loss was in Somalia when, it is thought, a round exploded in one of the plane's cannons.

There are 21 of the two types of AC-130 on "active duty", according to the US Air Force.