By Tim Robinson Aerospace International

The downing of an American special forces MH-47 Chinook helicopter, the first US aircraft to be shot down in the "war on terror", highlights the risks of this unconventional war, even for the world's most advanced military.

The B-52 can carry a phenomenal bombload

The helicopter - a heavily modified troop transport with air-to-air refuelling probe, defensive miniguns, night and low-level flying capability - represents the cutting edge of US technology that is being brought to bear in Afghanistan.

Similarly, in Afghanistan's Gardez region, the US Air Force has used prototype fuel-air thermobaric weapons in an effort to wipe out remaining hardcore al-Qaeda and Taleban fighters sheltering in caves.

The development of these weapons, along with advanced "bunker-busting" bombs with warheads that can tell the difference between concrete, earth, air gaps and living spaces is no accident.

They are products of US Gulf War experience, and were originally intended to destroy underground stocks of weapons of mass destruction.

Pointers for future

However, hi-tech helicopters and new lethal bombs are only half the story.

The Taleban possessed no air force and had very limited air defences

And although the US continues to strike al-Qaeda targets in Afghanistan, the initial rapid success of US military might and its Northern Alliance allies already suggest pointers for future defence planners, both for the US-led campaign and air power generally.

Prior to the beginning of the US attacks on Afghanistan in October most armchair pundits and military planners had expected a long drawn-out war against the al-Qaeda network and their Taleban hosts.

Yet, in December, the fearsome Taleban regime had collapsed and al-Qaeda's terrorist cells were on the run - what happened?

Key lessons

The answer is the United States' "transformational" use of air power, which throws up some key lessons for future conflicts.

The first lesson is that large stocks of precision weapons (or smart bombs) are now essential for any modern air campaign.

In the 1991 Gulf War the percentage of smart weapons used was 9%.

In Kosovo in 1999 this had risen to 29%, but cloud cover hindered employment of the laser-guided types.

In Afghanistan the figure is now between 60-70% with a large proportion of these being the low-cost ($18,000 a kit) 24-hour, all-weather satellite-guided JDAM (Joint Direct Attack Munition) bombs.

What this means is that, while in previous conflicts smart weapons were carefully rationed out for high-value targets like bridges or power stations, now even targets as small as perhaps a few Taleban fighters in a trench can now be considered a valid target to attack.

This, coupled with the ability to reduce the "sensor-to-shooter" loop - the time between a target being spotted and it being attacked by an aircraft, - means that US air power is much more lethal and precise than even a few years ago.

More importantly, while the Gulf War demonstrated the revolution in accuracy, Afghanistan has demonstrated the revolution in cost.

Precision is affordable and therefore available to all.

The second lesson follows on from this - in that the heavy bomber is back.

The B-52 is a 50-year-old design, yet it can carry a phenomenal bombload and can orbit over the battlefield waiting to be called on to bring down massive firepower on a helpless enemy.

In Afghanistan it has also been joined by B-1 and B-2 Stealth bombers.

This use of heavy bombers and precision weapons has made the line between what is strategic bombing and tactical close air support increasingly blurred, and to all intents and purposes meaningless.

Tactical bombing may have strategic results, while heavy strategic bombers can now perform close air support.

The third lesson is that information is key.

Without good intelligence and surveillance from satellites, unmanned spy drones and special forces on the ground, all the US investment in precision weaponry would have been useless.

The US Air Force is therefore investing heavily in these capabilities, particularly in space and unmanned aircraft sensors, to give it "information dominance" in any future conflicts.

Gap widening

Is Afghanistan then a new kind of war?

On the one hand it is important to remember some unique factors: the Taleban possessed no air force, had very limited air defences and was, despite its fundamentalist bluster, a very weak regime.

The US also had lots of support on the ground in the form of the Northern Alliance.

But what this conflict does show is how far the US, or more specifically the US Air Force, is ahead of its friends and enemies in terms of its revolutionary application of air power.

It is noteworthy that its nearest allies in Europe lack large stocks of smart bombs, heavy bombers or unmanned reconnaissance aircraft that were so critical in Afghanistan.

What is more is that, as the Pentagon's defence spending increases, this air power capability gap between the United States' abilities and the rest of the world is certain to get wider and wider.