Nearly half of all U.S. Apaches were deployed to Saudi Arabia following Iraq's invasion of Kuwait in 1990. During Operation Desert Storm on 17 January 1991, eight AH-64As guided by four MH-53 Pave Low IIIs destroyed part of Iraq's radar network in the operation's first attack, allowing the attack aircraft to evade detection. Each Apache carried an asymmetric load of Hydra 70 rockets, Hellfires, and one auxiliary fuel tank. During the 100-hour ground war, a total of 277 AH-64s took part, destroying 278 tanks, numerous armored personnel carriers and other Iraqi vehicles. One AH-64 was lost in the war, crashing after a close range rocket-propelled grenade (RPG) hit, the crew survived. While effective in combat, the AH-64 presented serious logistical difficulties. Findings reported in 1990 stated "maintenance units could not keep up with the Apache's unexpectedly high work load..." To provide spare parts for combat operations, the U.S. Army unofficially grounded all other AH-64s worldwide; Apaches in the theater flew only one-fifth of planned flight-hours. Such problems were evident before the Gulf War.