According to ABC News, the Army believes that a Russian-made SA-7/GRAIL was used to down that Apache attack helicopter in Iraq on Monday.
That revelation is rather surprising, since the Apache is equipped with an advanced self-protection system, designed to defeat a variety of shoulder-fired SAMs, including the 1960s-vintage SA-7. Saddam Hussein had thousands of man-portable SAMs in his arsenal; many went missing after the fall of Baghdad and are presumed to be in the hands of insurgents.
However, no self-defense suite is fool-proof. In rare cases, the system may fail to detect a missile launch. In other situations, maneuvers by the aircraft may actually prevent the missile from "acquiring" decoy flares or being blinded by a burst of laser energy. There is also a chance--albeit slim--that insurgents have somehow modified their SA-7s to make them more resistant to U.S. self-protection systems. However, such modifications are likely beyond the capabilities of insurgents, since they would require the installation of new, cooled seeker heads and/or infrared counter-countermeasure (IRCCM) circuitry.
A better explanation is that the insurgents are getting better training in MANPAD employment. In the past, terrorists in Iraq have utilized their shoulder-fired SAMs ineffectively, decreasing chances for a hit. Better employment tactics would increase the threat to Allied aircraft, but only slightly.
As we noted previously, the sudden rash of helicopter losses will prompt a review of U.S. helicopter tactics and counter-measures. In the chess game between our helicopters and ground threats, the enemy has made its latest move. Now, we'll make a counter-move to offset any advantage they might have gained.
On a related note, insurgents are reportedly using something called "Airborne Improvised Explosive Devices" against our choppers. Based on rudimentary media accounts, this weapon sounds like a large-caliber anti-aircraft artillery shell (perhaps 57 or 100mm), modified to explode at extremely low altitudes. Making that modification would simply require the installation of a new fuse, programmed to detonate at operating altitudes used by U.S. helicopters. The 57mm shell was originally designed to engage aircraft at medium altitude (up to 23,000 feet with radar guidance). Installation or modification of a low-altitude fuse is a relatively easy fix, within the realm of the terrorists' expertise.