So the army is taking the Longbow gear (two black boxes and the radar dome) off many of their AH-64Ds. This enables aircraft in Afghanistan to stay out a little longer, and be a bit more maneuverable at higher altitudes. In Iraq (and Afghanistan), it's one less maintenance headache for the support crews.
The next version of the Longbow will weigh only 400 pounds, and have more reliable, and easier to maintain, electronics. Against an enemy using lots of armored vehicles, the AH-64D, with its radar and a full load of 16 Hellfire missiles, is one of the more lethal anti-tank systems around. The current plan is to eventually upgrade all AH-64s to AH-64Ds.
The U.S. Army is stripping its helicopter gunships of some high-tech electronics, in order to save weight, and the hassle of maintenance. The AH-64D Apache Longbow has a radar based fire control system that enables it to spot armored vehicles, or stationary targets, in any weather, and up to ten kilometers away, and destroy them with Hellfire missiles (max range, eight kilometers). Introduced in the late 1990s, this was a late Cold War development, the perfect weapon to destroying enemy tanks at long range. The AH-64D got some use during the 2003 Iraq invasion, but since then, the Longbow radar has been more of a liability. The radar system has not been much use for firing Hellfires at targets in residential areas, where you usually want to get a visual, not radar, picture of the target. Moreover, the radar system weighs 500 pounds (about three percent of the weight of a fully loaded AH-64D). In Afghanistan, where the AH-64s fly at high altitudes, where the thin air means less lift, losing three percent of your weight is appreciated. In Iraq, the high heat, and abundant dust, makes the Longbow electronics more prone to breakdown.