For thirty years the Pentagon's wager — that American precision could substitute for Soviet mass — had been an argument in academic journals and white papers. In January 1991, on a planet's worth of television sets, it became proof. Of all coalition ordnance dropped on Iraq, only ~8% was precision-guided. That 8% destroyed the country's nervous system. None of it would have existed without American silicon.
On February 25, 1991, a Scud missile struck a barracks at Dhahran housing the 14th Quartermaster Detachment. 28American soldiers were killed. 98were wounded. The worst single American loss of the war.
The Patriot battery that should have engaged the incoming Scud had not fired. Investigators traced the failure to a software bug in the system's range-gate timing. The Patriot's computer kept time in a 24-bit fixed-point register; it multiplied tenths of a second by an approximation of one tenth that, because one tenth has no exact binary representation, drifted by a tiny amount each cycle. After the battery had been running continuously for around 100 hours, the cumulative error had grown to about a third of a second. A Scud, traveling at roughly a mile per second, was therefore searched for in the wrong patch of sky.
Raytheon had identified the bug and shipped the patched software days earlier. The patched tape arrived in Dhahran the day after the strike.
Postwar studies (GAO 1992; Postol/MIT) concluded only ~9%of Patriot–Scud engagements over Saudi Arabia could be supported by strong evidence of a warhead kill. The political function of the Patriot — keeping Israel out of the war, reassuring Saudi cities — had been real. The advertised technical performance had not.
Of all coalition air-delivered ordnance dropped on Iraqi targets between January 17 and February 28, 1991, only about eight percent was precision-guided. The other ninety-two percent consisted of the same iron bombs that had been dropped over Germany in the 1940s and Vietnam in the 1960s, dropped this time by B-52s flying high-altitude carpet patterns over Iraqi divisions. The two halves of the campaign were complementary: the smart bombs collapsed Iraq's nervous system; the dumb bombs broke its body. Both were necessary. Only one made television.
SOURCE · GULF WAR AIR POWER SURVEY VOL. IV · COHEN, 1993