Three UK soldiers died from "friendly fire"
Grid references were confused before a US aircraft dropped a 500lb bomb which killed three UK soldiers in Afghanistan, an inquest has heard.
Pte Aaron McClure, from Suffolk, Pte Robert Foster and Pte John Thrumble, both from Essex, died in August 2007.
They were under heavy fire when an F15, called to help, bombed them instead of a Taliban position 1km further north.
Coroner David Masters told the hearing in Trowbridge, Wiltshire, that British and US co-ordinates "did not marry up".
All three soldiers were members of the 1st Battalion The Royal Anglian Regiment.
They were among about 100 troops from Seven Platoon involved in a series of offensive patrols in abandoned villages.
They were hoping to take out a sniper in Kaji but were confronted by "some of the most intense fighting" experienced by B Company, Mr Masters said.
Pte McClure, 19, from Ipswich, and Pte Thrumble, 21, from Maldon, were at an observation post on the roof of a building in nearby Mazdurak.
Pte Foster, 19, from Harlow, was inside the house firing from a window when Maj Antony Borgnis ordered the air strike.
Sgt Mark Perren, a forward air controller, passed on Maj Borgnis' order to the Weapons Support Officer aboard the US aircraft.
Mr Masters said Sgt Perren would give evidence to say he was struggling to communicate without a head set.
He would deal with the grid references he gave the US plane and the grid references confirmed back, which were later found not to marry-up, Mr Masters said.
The coroner also said the inquest would hear that Sgt Perren did not deliver a nine-liner - a document setting out the information needed by the aircraft to drop the bomb.
"There was an incorrect clarification of the grid references," Mr Masters added.
Sgt Perren was investigated but no charges were brought against him, the inquest heard.
Pte McClure and Pte Thrumble were killed instantly in the blast and were evacuated under mortar fire along with injured L/Cpl Stuart Parker and Pte Joshua Lee.
Mr Masters said when the forces returned to base they realised Pte Foster was not with them.
A search party later pulled him from the rubble using their bare hands, the coroner said.
Post-mortem tests showed he died of asphyxia caused by entrapment following an explosion.
In a statement Seven Platoon commander Lt George Seal-Coon described the explosion.
"I suddenly saw a big, white flash surround me and I ducked down," he said.
"I felt a shockwave pass through my body, followed by the feeling of being surrounded by red and an intense heat. Then all I saw was dust and smoke."
After the roof collapsed, he put Pte McClure on a stretcher.
He said a head-count had been carried out before they had left and that they would not have left Mazdurak had they realised anyone had not been accounted for.
Four investigations were carried out into the incident, including a Combined Investigation Board inquiry conducted by the Americans with a UK services representative.
Its report only arrived on Monday which meant the hearing would be adjourned until February to allow it to be fully examined, the inquest was told.