Analysis: 'Friendly fire' danger

Canadian troops were in a designated exercise area

By Jonathan Marcus BBC defence correspondent

Modern combat is by definition a hazardous and unpredictable activity, and soldiers are accidentally killed by their own side in most conflicts.

Nine British soldiers were killed by US fire during the Gulf War

But so called friendly fire incidents - certainly for Western armies - have become much more controversial in recent years for a whole variety of reasons.

For one thing, technology has improved dramatically.

When things work properly weapons can be launched against specific targets with unparalleled levels of accuracy.

Tragic mistakes

But this improvement in accuracy means that targets have to be designated or identified with equivalent precision in the first place.

Friendly fire incidents involving US forces

Afghanistan, April 2002: Four Canadian soldiers killed by US bomb during training exercise

Dec 2001: Three US soldiers, six Afghan allies killed by US bomb from warplane

Persian Gulf, 1991: Nine Britons killed by US warplane strike

35 American soldiers killed in series of incidents involving "friendly fire"

Procedures can go wrong, mistakes can be made, and even small technical factors can play a part.

For example, last November a US warplane wounded a number of US and allied soldiers when it targeted a prison compound west of Mazar-e-Sharif.

The satellite-guided bomb steered exactly to the coordinates it had been given by a forward air controller on the ground.

Tragically, this soldier had just changed the batteries of his GPS receiver and, in the heat of battle, he had forgotten that when batteries are changed the machine reverts to displaying its current position.

It was this target location - his own - that he sent to the aircraft.

'Significant proportion'

"Friendly fire" incidents must also be set against the sensitivity to casualties, particularly prevalent in the US.

The US will be looking at where the procedures for authorising the release of a weaponry need to be tightened up

This should not be overstated in the wake of 11 September.

The US military, and ordinary Americans for that matter, are clearly willing to accept casualties as an inevitable part of fighting a war that has strong public support.

But in a whole succession of recent wars from the liberation of Kuwait onwards, the relatively low casualty toll for Western forces means that deaths from friendly fire represent a significant proportion of the casualties.

Political sensitivities also play a part, as so much of the air power is American, and as often as not the casualties are its allies.

New technology

Well-known examples would be anti-Taleban forces in Afghanistan, or the latest incident involving the death of four Canadian soldiers.

It is hoped new technology will reduce the numbers of soldiers killed by friendly fire

In the 1991 Gulf British troops in their Warrior armoured vehicles were attacked by US warplanes, nine were killed.

In the wake of the Gulf War huge efforts have been put into finding technical means by which solders can identify themselves to friendly forces.

Transponders and other devices can alert a tank or aircraft to the fact that it has a friendly unit in its sights.

But this is much easier to do for vehicles than it is for dispersed infantry units on the ground.

Here too though there is much investment - especially to help small unit commanders identify their own men in urban fighting scenarios.

But it is going to be some time before every soldier is so equipped, and such identification systems raise all sort of questions about how US forces will operate alongside less technologically advanced allies.

Investigation

This latest episode is even more perplexing since the Canadian troops attacked were in a designated exercise area rather than engaged in offensive operations.

The US F-16 aircraft involved came from the Air National Guard, prompting some people to raise questions about their suitability for combat operations.

However these part-time reserve units are stocked with experienced pilots, and are an integral part of the US Air Force's strength.

An urgent investigation is already underway to find out why the Canadian unit was designated as a hostile target.

The US will also be looking at where the procedures for authorising the release of a weaponry need to be tightened up.