An RAF Tornado has crashed and its crew have died after being downed by a US Patriot missile near the Iraq border.
A US Patriot missile system shot down the RAF Tornado
Simon Turner, a former RAF Harrier pilot, examines how such tragic accidents can occur during military operations.
Friendly fire, blue on blue and fratricide, are all official terms that servicemen are well used to hearing, take many measures to avoid and dread the prospect of.
Most of us can imagine how - in a situation where ground troops are fighting an enemy of relatively unknown hostility, spread over a very large country - confusion from the 'fog of war' can cause a friendly fire incident.
But given the size and scope of the ground invasion there have been few reports of such incidents on the ground.
Friend or foe?
But there have been several incidents of friendly action causing deaths in the air.
Many people will ask how an RAF Tornado could be downed by an American Patriot Missile System given the technology used by both of these weapons systems.
Returning from its mission, the Tornado should have been following assigned routing. This is designed to allow safe passage to friendly aircraft.
What could have gone wrong?
It would have been sending out electronic signals from its Identification Friend or Foe (IFF) equipment to show it as a friendly aircraft on coalition radar.
Once in friendly airspace, it would also have adopted a non-hostile flight profile, slow speed with lights on. A profile that no Iraqi Mig pilot would adopt if he managed to reach coalition territory.
The missile system would have been at the highest alert state ready to intercept Iraqi surface-to-surface missiles, potentially carrying chemical or biological agents.
It would have its own block of sky assigned to it, a Weapons Free Zone' (WFZ) that the Tornado crew would have known the whereabouts of.
The Patriot operator is at liberty to engage any target that enters his WFZ. It is possible that this could happen automatically. This is understandable if you consider the crew have only a very few seconds in which to decide and shoot at a Scud Missile before it lands.
It is hard to imagine that the two crew Tornado would have simply wandered unknowingly into the Patriot's WFZ and been shot.
The crews are too experienced and capable and their navigational equipment too sophisticated.
There are many other coalition systems that monitor the air picture to guard against such simple errors (like the Awacs Airborne Early Warning aircraft). The Awacs would be in radio contact with all aircraft and able to provide radio instructions if one of them began to head towards a friendly WFZ.
It is possible that the Tornado crew had experienced some sort of serious electrical failure with maybe an onboard fire.
It could well have lost its communications, navigational and IFF equipment as a result. They may then have been forced to head directly back to base with their aircraft in flames, off the normal routing and into the Patriot WFZ.
They would now be busy and possibly not aware of their exact position, but would be expected to adopt a non-hostile 'lame duck' posture, slow speed etc, if they were going to enter the WFZ.
The Patriot operator would have seen the aircraft entering its warning area. He would have prepared to engage whilst checking that the potential target was hostile.
But given that we have not heard of a single Iraqi aircraft launch, it is reasonable to assume that the Patriot operator could take time to verify the nature and identification of any aircraft on his scope.
Ongoing risk assessment would more than likely reveal that there is more chance of a friendly aircraft wandering into a WFZ than there is of a hostile Iraqi Mig.
Even at high speed, the flight profiles and signal returns from an aircraft and missile would look very different on radar.
The operator should have had time to make further checks on the aircraft's identity, even contacting other agencies like the Awacs.
If the Tornado had looked like an Iraqi aircraft threat, the Patriot operators should have expected advanced warning that such a threat had been seen launching and was heading his way. This was clearly not the case.
Coalition Forces will treat this incident very seriously, some hard questions will rightly, be asked. No doubt new procedures will be introduced to guard against such a similar eventuality happening in future.
However casualties from other types of friendly action have been more significant than casualties to enemy action. Is this bad luck or to be expected in a conflict of this scale?
The American CH53 crash that killed 8 Royal Marines and 4 US servicemen was reported as a technical failure. Given the age, its relatively poor accident statistics and the complex mechanical nature of the craft, this is a very likely cause.
Accidents due to mechanical failure do occur and are an accepted risk of military operations. They are however, no less tragic when they happen.
A mid-air collision between two Royal Navy Sea King helicopters killed seven servicemen. This was another tragic event that happened well away from the "fog of war" in international waters.
An investigation is underway, but it could have been caused by a combination of operational risks, environmental conditions and sheer bad luck.