It's a sad fact that blue on blue's still occur, but whenever there is war, and confusion, errors are bound to happen.
To criticise the pilots, from 1g, at the comfort of your anonymous desktop, when you have never done hot CAS yourself, is a questionable thing to do. The A-10 is a complete CAS platform; that is all they train to do, they are damn good at it, and if they are making errors then these are errors that anyone could make.
The unsavoury thing here is the lack of IFF technology that could easily be employed, and the fact that the Forward Air Controller thought he knew that there were no friendlies in the area. All the parties concerned did what they thought was the right thing to do, at the time. That is all we can ask of people who's lives are in danger themselves. Isn't hindsight a wonderful thing.
Blue on blues can be mitigated against with technology, and this is something that the MOD needs to invest in heavily, and urgently.
My thoughts are with Lance Corporal Hull's family.