In the 1990s, the United States retired it's EF-111 electronic warfare aircraft (they were expensive to operate) and ordered the air force and navy to pool their resources and support the navy fleet of EF-6B aircraft. Thus the U.S. has only has 95 electronic attack aircraft that can defend groups of warplanes heading into heavily defended (especially by radar guided missiles and guns) enemy territory. These EA-6Bs are all over thirty years old. Last week, a metal fatigue problem forced 24 of these aircraft to be grounded for repairs. This comes after 19 EA-6Bs were grounded for the same reason two months ago. That's 45 percent of the EA-6B force. The navy says it will be two years before all 95 EA-6Bs are available for service, although more of the 43 EA-6Bs will come back online starting early next year. The navy is planning on replacing the aging EA-6Bs with a modified F-18 (as the EA-18G), but these won't be available until 2008. Further down the road, there are also plans to try fitting the F-35 as an electronic warfare aircraft. The EA-6Bs are fitted radar detectors, radar jammers and equipment operators trained to quickly detect and jam likely enemy radars to be encountered. At the moment, the EA-6Bs would be most needed if North Korea attacked.