From the most recent edition of "Inside the Ring" in the Washington Times. Military officials in Baghdad report that Air Force F-16s have destroyed four terrorist anti-aircraft guns that may have played a role in that recent spate of helicopter losses.
According to the Times' Bill Gertz, American UAVs patrolling over Baghdad discovered that insurgents had mounted heavy machineguns in the backs of pickup trucks, and covered the weapons with tarpaulins. When they heard the sound of an approaching helicopter, the terrorists would stop, uncover the weapon and begin firing. After engaging the choppers, terrorist gunners would cover the machinegun and drive away, complicating coalition targeting efforts.
Unfortunately for the bad guys, persistent surveillance from UAVs (mostly Predators) allowed intelligence analysts to identify and track the gun trucks, sometimes referred to as technicals. Once their locations were pinpointed, commanders called in airstrikes that eliminated the threat. The recent introduction of the 250-lb small diameter bomb has further improved our ability to strike small targets, even in a crowded, urban environment.
Obviously, destruction of these gun trucks won't completely eliminate the threats faced by coalition helicopters. But it will send the terrorists back to the drawing board, in search of more effective ways to "surprise" our choppers--and preserve their own, limited air defense assets.