were damaged; one was shot down in an unsuccessful attack on an Iraqi Republican Guard armored brigade near Karbala. Iraqi tank crews had set up a "flak trap" among terrain and effectively employed their guns. Iraqi officials claimed a farmer with a Brno rifle shot down the Apache, but the farmer denied involvement. The AH-64 came down intact and the crew were captured; it was destroyed via air strike the following day. By the end of U.S. military operations in Iraq in December 2011, several Apaches had been shot down by enemy fire and lost in accidents. In 2006, an Apache was downed by a Soviet-made Strela 2 (SA-7) in Iraq, despite it being typically able to avoid such missiles. In 2007, four Apaches were destroyed on the ground by insurgent mortar fire using web-published geotagged photographs taken by soldiers. Several AH-64s were lost to accidents in Afghanistan. Most Apaches that took heavy damage were able to continue their missions and return safely. By 2011, the U.S. Army Apache fleet had accumulated more than 3 million flight hours since the first prototype flew in 1975. A DOD audit released in May 2011 found that Boeing had frequently overcharged the U.S. Army for routine spare parts in helicopters like the Apache, ranging from 33.3 percent to 177,475 percent. On 21 February 2013, the 1st Battalion (Attack), 229th Aviation Regiment at Joint Base Lewis–McChord became the first U.S. Army unit to field the AH-64E Apache Guardian; a total of 24 AH-64E were received by mid-2013. On 27 November 2013, the AH-64E achieved initial operating capability (IOC). In March 2014, the 1st–229th Attack Reconnaissance Battalion deployed 24 AH-64Es to Afghanistan in the type's first combat deployment. From April through September 2014, AH-64Es in combat maintained an 88 percent readiness rate. The unit's deployment ended in November 2014, with the AH-64E accumulating 11,000 flight hours, each helicopter averaging 66 hours per month. The AH-64E flies faster than the AH-64D, cutting response time by 57 percent, and has better fuel efficiency, increasing time on station from 2.5–3 hours to 3–3.5 hours; Taliban forces were reportedly surprised by the AH-64E attacking sooner and for longer periods. AH-64Es also worked with medium and large unmanned aerial vehicles (UAVs) to find targets and maintain positive ID, conducting 60 percent of the unit's direct-fire engagements in conjunction with UAVs; Guardian pilots often controlled UAVs and accessed their video feeds