The AH-64 Apache is a four-blade, twin-engine attack helicopter with a tailwheel-type landing gear arrangement, and a tandem cockpit for a two-man crew.

The Apache was developed by Hughes Helicopters for the United States Army's Advanced Attack Helicopter program to replace the AH-1 Cobra. In 1982, the Army approved full production of the Apache. McDonnell Douglas continued production and development after purchasing Hughes Helicopters in 1984. The helicopter unit later became part of The Boeing Company with the merger of Boeing and McDonnell Douglas in August 1997.

First flown on 30 September 1975, the AH-64 features a nose-mounted sensor suite for target acquisition and night vision systems. The Apache is armed with a 30-millimeter (1.2 in) M230 Chain Gun carried between the main landing gear, under the aircraft's forward fuselage. It has four hardpoints mounted on stub-wing pylons, typically carrying a mixture of AGM-114 Hellfire missiles and Hydra 70 rocket pods. The AH-64 features multiple aircraft systems with built-in redundancy to improve survivability in combat; improved crash survivability for the crew has also been prioritized.

The first production AH-64D Apache Longbow, an upgraded version of the original Apache, was delivered to the Army in March 1997.

The U.S. Army is the primary operator of the AH-64; it has also become the primary attack helicopter of multiple nations, including Greece, Japan, Israel, the Netherlands and Singapore; as well as being produced under license in the United Kingdom as the AgustaWestland Apache. U.S. AH-64s have served in conflicts in Panama, Persian Gulf War, Kosovo War, Afghanistan, and Iraq. Israel has made active use of the Apache in its military conflicts in Lebanon and Gaza Strip, while two coalition allies have deployed their AH-64s in Afghanistan and Iraq.

Source: Wikipedia, "McDonnell Douglas AH-64 Apache", available under the CC-BY-SA License.