In April 2006, Boeing was awarded $67.6M fixed-price contract
for the remanufacture of several existing U.S. AH-64As to the AH-64D
configuration; between May 2009 and July 2011, a further five contracts were
issued to remanufacture batches of AH-64As to the upgraded D variant. Since
2008, operation of older AH-64A has been recommended to undertake modernization
programs to become AH-64Ds, given Boeing& U.S. Army plans to terminate
support for the A-variants in the near future. Apache effectiveness against
ground forces has been bolstered by the addition of the AGM-114N – a Hellfire
missile fitted w/ thermobaric warhead, approved for full production in 2005.
McDonnell Douglas studied an improved AH-64B design w/ updated
cockpit, & other upgrades in the mid-1980s. In 1988, funding was approved
for a multi-stage upgrade program to improve sensor and weapon avionics systems
and incorporate some digital systems. However, rapidly improving technology led
to the upgrade program being canceled in favor of more ambitious changes.
Development of the more advanced AH-64D Apache Longbow was approved by the
Defense Acquisition Board in August 1990. AH-64D prototype testing ended in
April 1995. During the testing, six AH-64D helicopters were pitted against a
numerically superior group of AH-64A helicopters & results demonstrated that
AH-64D has a seven times increase in survivability and four times increase in lethality
compared to the AH-64A.
Full-scale production of the Apache Longbow was approved in October 1995 w/ $1.9-billion five-year contract signed in August 1996 to upgrade & rebuild 232 existing AH-64A Apaches. The first production AH-64D flew in March 1997 & cost of AH-64D program totaled $11bn through 2007. Agusta Westland had been producing Apache components for the international market, but
since 2004, Korea Aerospace Industries has been the sole manufacturer of the Apache's fuselage. Prior to this, fuselage production was handled by Teledyne Ryan Aeronautical during the 1980s & ‘90s but legal dispute between Teledyne Ryan and Boeing broke out over the eventual transfer of fuselage production.