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The H-1 upgrade program refers to the United States Marine Corps's program to develop the AH-1Z Viper and UH-1Y Venom to replace its aging fleets of AH-1W SuperCobras and UH-1N Twin Hueys. The former is a twin-engine attack helicopter, while the latter is a medium-sized utility helicopter, also twin-engined. The contract was awarded to Bell Helicopter, the original designer and manufacturer of both helicopters, to design these new airframes as modernized attack and utility helicopters with considerable design commonality to reduce operating costs. ==Development== In August 1995, the Secretary of the Navy authorized the Marine Corps to upgrade its utility and attack helicopters as a bridge until the Joint Replacement Aircraft was available in 2020.〔(H-1 Upgrade Program ) on GlobalSecurity.org〕 In 1996, the Marine Corps launched the H-1 upgrade program by signing a contract with Bell for upgrading 180 AH-1Ws into AH-1Zs and upgrading 100 UH-1Ns into UH-1Ys.〔Donald, David. ''Modern Battlefield Warplanes''. AIRTime Publishing, 2004. ISBN 1-880588-76-5.〕〔Bishop, Chris. ''Huey Cobra Gunships''. Osprey Publishing, 2006. ISBN 1-84176-984-3.〕 While the original contract called for upgrading existing airframes, it was later modified in 2008 to manufacture completely new aircraft.〔〔Warwick, Graham. ("Bell AH-1Z upgrade to switch to new airframes" ), Flightglobal.com, 15 February 2008.〕 The program also includes aircraft simulators.〔(USMC H-1 Upgrade Program ), Advanced Simulation Technology, Inc., September 2005〕 Richard Aboulafia, an analyst at the Teal Group, suggests that the motivation to upgrade the H-1s instead of buying new Sikorsky UH-60 Black Hawk and Boeing AH-64 Apache helicopters was to avoid risk to the Bell-Boeing V-22 Osprey program.〔("AH-1Z Viper enters production as substantially new aircraft." ) ''FlightGlobal'', 20 December 2010.〕 The AH-1Z first flew on 8 December 2000.〔("AH-1Z completes first flight" ), Bell Helicopter, 7 December 2000.〕 Three prototype aircraft were delivered to NAVAIR's Naval Air Station Patuxent River in July 2002 for the flight test phase of the program. Low-rate initial production followed beginning in October 2003,〔〔(Defense Dept. `Green Lights' Bell's H-1 Upgrade Program ) Business Wire, October 2003〕 with deliveries to run through 2018,〔("AH-1Z/UH-1Y complete developmental testing" ), US Navy, 6 March 2006.〕 however, full-rate production was delayed until 2005.〔 The AH-1Z completed sea-trial flight testing in May 2005.〔("AH-1Z/UH-1Y complete first sea trials" ). US Navy, 13 June 2005.〕 On 15 October 2005, the USMC, through the Naval Air Systems Command, accepted delivery of the first AH-1Z production helicopter to enter the fleet.〔("Bell 449 SuperCobra and KingCobra" ), Jane's Information Group, 7 December 2005.〕 During the first quarter of 2006, the first production model UH-1Y completed its first flight, and the aircraft were transferred to the Operational Test Unit at the NAS Patuxent River to began operational evaluation (OPEVAL) testing.〔("AH-1Z/UH-1Y Start OPEVAL" ), US Navy, 6 May 2006.〕 In February 2008, Bell received a contract for the last 40 AH-1Zs to be built as new airframes instead of the previously planned rebuild of AH-1Ws.〔 Also that same month, the AH-1Z and UH-1Y began the second and final portion of OPEVAL testing.〔Warwick, Graham. ("US Marine Corps' Bell AH-1Z and UH-1Y enter final test phase" ), Flightglobal.com, 20 February 2008.〕 Bell delivered three upgraded H-1s to the Marine Corps in February 2008.〔("Bell H-1 upgrade program delivers two UH-1Y and one AH-1Z in February" ). Bell Helicopter, 3 March 2008.〕 In September 2008, the NAVAIR proposed adding 46 additional AH-1Zs bringing the total number ordered to 226. The additional aircraft will appear on the 2010 fiscal budget request. The final number of UH-1Y acquisitions was also set at 123.〔 Full-rate production was approved in late 2008.〔 On September 30, 2008, Bell received a contract for Lot 5 H-1 aircraft. These 15 aircraft in Lot 5 include 11 UH-1Ys and four AH-1Zs, bringing the total contacted amount to 49 upgraded H-1 aircraft for the Marine Corps: 37 UH-1Ys and 12 AH-1Zs. At that time, the company had delivered 20 upgraded H-1 helicopters: 14 UH-1Ys and six AH-1Zs. On March 27, 2009, the Navy Department ordered 16 Lot 6 H-1 helicopters. The 16 aircraft in Lot 6 include five AH-1Zs and 11 UH-1Ys, bringing the total contract to produce a total of 65 upgraded H-1 aircraft: 17 AH-1Zs and 48 UH-1Ys. At the time, Bell had delivered 23 upgraded H-1 helicopters: six AH-1Zs and 17 UH-1Ys. In May 2009, several helicopters were grounded after a manufacturer's defect was detected in the gearbox. The aircraft deployed with the 13th Marine Expeditionary Unit were not affected. In September 2009, the UH-1Y entered full rate production, with the Marine Corps expected to receive 21 aircraft by the end of the year. The AH-1Z reached initial operational capability in September 2010, and was approved to begin full-rate production on 10 December 2010. The AH-1Z is expected to cost approximately each.〔 Program manager Colonel Harry Hewson expressed interest in exporting the upgraded aircraft via Foreign Military Sales at the 2010 Farnborough Airshow. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「H-1 upgrade program」の詳細全文を読む スポンサード リンク
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