Upon fielding the Apache, capabilities such as the FLIR's use in extensive night operations made it clear that it was capable of operating beyond the forward line of own troops (FLOT) to which previous attack helicopters were normally restricted. It was discovered that the Apache was coincidentally fitted with the Have Quick UHF radio system used by the U.S. Air Force, allowing inter-service coordination and joint operations such as the joint air attack teams (JAAT). The Apache have operated extensively with close air support (CAS) aircraft, such as the USAF's Fairchild Republic A-10 Thunderbolt II and the USMC's McDonnell Douglas AV-8B Harrier II, often acting as a target designator to conserve the Apache's own munitions. The Apache was first used in combat in 1989, during Operation Just Cause, the invasion of Panama. It participated in over 240 combat hours, attacking various targets, mostly at night. General Carl Stiner, the commander of the operation, stated: "You could fire that Hellfire missile through a window from four miles away at night."