The Israeli guns were firing at near-maximum range - 10 miles - and firing over the UN base at Hizbollah rocket launchers 300 yards to the north. At that range, Israeli sources said, the natural dispersion of shells in an elliptical pattern along the line of fire led some to fall short.
The UN military adviser to the Secretary-General, General Frank van Kappen, arrived in Beirut on Friday, the day after the Qana shelling, to conduct an investigation into the attack. He will also visit Jerusalem before submitting his report.
The UN said yesterday that six 155mm shells landed within the UN base. Between 50 and 70 shells landed in the Qana area during that day.
Israeli sources denied suggestions that the attack on the UN base was deliberate. Although both the UN and the Israeli Defence Forces have not yet completed formal investigations, it now looks likely that the artillery commander on the spot will be blamed for ignoring the safety margin around the known Fijian UN base at Qana and firing too hastily on the position from which Hizbollah had fired a number of BM-21 rockets.
It now seems clear that the Israelis fired as quickly as possible, to hit the Hizbollah gunners before they could escape, and did not fire ranging shots. Had the Hizbollah position been to one side of of the UN base, relative to the position of the guns, there might not have been a problem. However, the UN said the Hizbollah position was directly north of the UN base, only 300 yards away.
The M109A1 self-propelled howitzers used by the Israelis have a maximum range of about 18km, and were, according to Israeli sources, firing from 15km or 16 km. At that range, the shells will spread across a "beaten zone" along the line of fire. Some will land short or beyond the target.
Had the Israelis observed the "safety ring", they would not have risked some of the shells falling into the UN base. It appears that on this occasion a local commander may have ignored the standing orders which have a "safety ring" around each known UN site. The UN has had troops in the Qana base for 18 years.
According to UN sources in Lebanon, the Israeli shells were fitted with M732 radar fuses, which detonate them at 7m off the ground, the most lethal possible height, blasting fragments downwards to amputate, maim and kill.
The Israelis were using a US-built radar system, "Firefinder", to detect and plot the launch of the Hizbollah rockets. The radar will plot the position to within a ten-figure grid reference. This is then keyed into the fire control computer, which will produce settings for each of the guns distributed around the firing positions, so that their fire will converge on the target. However, at near- maximum range there will still be some dispersion. The Israeli sources also suggested the coordinates may not have been transcribed accurately.