Equipping the U.S. Army's 2,500 helicopters with defenses against shoulder fired surface-to-air missiles (like the SAM-7 or Stinger), would cost $5-7 billion and take up to a year, or more to implement. A typical system has two components. First, there are four ultraviolet detection sensors (weighing about four pounds each) mounted on different parts of the helicopter to detect an approaching missile. These sensor are linked to an eleven pound computer that contains software for determining that the object is indeed a missile and where it is headed. The detection computer is hooked to a countermeasures system using either flares and chaff (strips of metal foil), or a laser, to confuse the missiles guidance system (that is homing in the heat of the helicopters engines.) The countermeasures component weighs 30-50 pounds, depending on type or model. 

There is a debate going on inside the army over whether to equip helicopters with the army developed ATIRCM/CMWS (Advanced Threat Infrared Countermeasures/Common Missile Warning System), that uses flares and chaff, or a civilian system (DIRCM), that uses a laser to confuse the missiles guidance system. The DIRCM costs about 40 percent more than the ATIRCM/CMWS (which costs two million dollars per aircraft). The ATIRCM/CMWS uses a proven technology, which the DIRCM's laser has been successful in tests, but has not gotten much use in actual combat conditions. Because both systems use a lot of precision components, and  a lot of them cannot be produced quickly. The army has equipped some of its Special Forces helicopters with DIRCM, but it would take about the same amount of time (late 2005, early 2006) to equip all army helicopters with either system. Many of the army's larger transport helicopters are equipped with an older, and less reliable, countermeasures system. So far, ten American helicopters have been hit by missiles in Iraq. If the attacks continue to bring down choppers, there will probably be a crash program to equip the most vulnerable helicopters (those operating over the few areas where most of the attacks occur) with a defensive system as soon as possible. This means 30-90 days.