Editing Lockheed P-3 Orion (section)

===Further developments===
[[File:US Navy 100706-N-6855K-063 P-3C Orion aircraft from the navies of the Japan Maritime Self-Defense Force, Canada, Australia, Republic of Korean and the U.S. line the Rainbow Fleet tarmac of Marine Corps Air Station Kaneohe Bay.jpg|thumb|P-3s from Japan, Canada, Australia, Republic of Korea, and the United States at [[MCAS Kaneohe Bay]] during RIMPAC 2010]]

In 1963, the U.S. Navy's [[Bureau of Naval Weapons]]  contracted [[Univac]] Defense Systems Division of [[Sperry Rand]] to engineer, build, and test a [[digital computer]] (a device then in its infancy) to interface with the many sensors and newly developing display units of the P-3 Orion. Project A-NEW was the engineering system, which  after several early trials, produced the engineering prototype, the [[CP-823/U]], [[Univac 1830]], Serial A-1, A-NEW MOD3 Computing System. Univac delivered the CP-823/U to the [[Naval Air Development Center]] at Johnsville, Pennsylvania, in 1965; this directly led to the production computers later equipped on the P-3C.<ref>Thomas, Todd J. [http://www.p3oriontopsecret.com "First Digital Airborne Computing System: UNIVAC 1830, CP-823/U Serial A-New Mod 3, Engineering Prototype Lockheed P-3 Orion."] {{Webarchive|url= https://web.archive.org/web/20110715031714/http://www.p3oriontopsecret.com/ |date= 15 July 2011 }} ''p3oriontopsecret.com,'' 2010. Retrieved: 9 December 2010.</ref>

Three civilian Electras were lost in fatal accidents between February 1959 and March 1960. Following the third crash, the FAA restricted the maximum speed of Electras pending determination of the causes. After an extensive investigation, two of the crashes (those of September 1959 and March 1960) were identified as due to insufficiently strong engine mounts, unable to damp a whirling motion that could affect the outboard engines. When the oscillation was transmitted to the wings, a severe vertical vibration escalated, tearing off the wings.<ref name=Serling>Serling, Robert J., ''Loud and Clear'', Dell, 1970.</ref><ref name="inquest">[http://www.flightglobal.com/pdfarchive/view/1961/1961%20-%200225.html Lessons of a turboprop inquest] {{Webarchive|url=https://web.archive.org/web/20121104081345/http://www.flightglobal.com/pdfarchive/view/1961/1961%20-%200225.html |date=4 November 2012 }} ''Flight'' 17 February 1961 p.225</ref> The company implemented a costly modification program, labelled the Lockheed Electra Achievement Program, which strengthened the engine mounts and the wing structures supporting the mounts, and replaced some wing skins with thicker material. At its own expense, Lockheed modified all surviving Electras of the 145 built at that time, the process taking 20 days for each aircraft. These changes were incorporated into subsequent aircraft as they were built.<ref name=Serling/>

The Electra's sales were limited as Lockheed's technical fix did not completely erase the aircraft's poor reputation in an era in which turboprop-powered aircraft were being replaced by faster jets.<ref>Murphy, Pat. [https://web.archive.org/web/20071012195147/http://www.mtexpress.com/story_printer.php?ID=2005116805 "Fighting fire like a regular military ground, air war: Onetime jinxed airliner now a superstar fire bomber."] ''mtexpress.com,'' 2010. Retrieved: 16 November 2010.</ref> In military roles that valued fuel efficiency more than speed, the Orion remained in service for over 50 years after its 1962 introduction. Although surpassed in production longevity by the [[Lockheed C-130 Hercules]], 734 P-3s were produced through 1990.<ref name=aeroflight2010>[http://www.aeroflight.co.uk/aircraft/types/lockheed-martin-p-3-orion.htm "Lockheed Martin P-3 Orion."] {{Webarchive|url=https://web.archive.org/web/20101111053033/http://www.aeroflight.co.uk/aircraft/types/lockheed-martin-p-3-orion.htm |date=11 November 2010 }} ''Aeroflight.co.uk,'' 31 July 2010.</ref><ref>[http://www.fas.org/programs/ssp/man/uswpns/air/asw/p3.html "P-3 Orion Overview."] {{Webarchive|url= https://web.archive.org/web/20101123034704/http://www.fas.org/programs/ssp/man/uswpns/air/asw/p3.html |date= 23 November 2010 }} ''Federation of American Scientists (FAS).'' Retrieved: 25 January 2011.</ref><ref name=idaret>{{cite news |url= https://news.google.com/newspapers?id=Y5UrAAAAIBAJ&pg=5942%2C1365745 |work= Idahonian |location= (Moscow) |agency= Associated Press |last= Barbour |first= John |title= Retooling the war machine |date= 14 July 1990 |page= 6C}}</ref> Lockheed Martin opened a new P-3 wing production-line in 2008 as part of its Service Life Extension Program (ASLEP) for delivery in 2010. A complete ASLEP replaces the outer wings, center-wing lower section, and horizontal stabilizers with newly built parts.<ref>[http://www.deagel.com/news/Lockheed-Martin-Awarded-Contract-to-Build-Outer-Wing-Sets-for-the-US-Navys-P-3-Orion-Fleet_n000004921.aspx "Lockheed Martin Awarded Contract to Build Outer Wing Sets for the US Navy's P-3 Orion Fleet."] {{Webarchive|url= https://web.archive.org/web/20110918180557/http://www.deagel.com/news/Lockheed-Martin-Awarded-Contract-to-Build-Outer-Wing-Sets-for-the-US-Navys-P-3-Orion-Fleet_n000004921.aspx |date= 18 September 2011 }} ''deagel.com,'' 4 September 2008.</ref>

In the 1990s, the U.S. Navy attempted to procure a successor aircraft to the P-3, and selected the improved [[Lockheed P-7|P-7]] over a naval-specific variant of the twin turbofan-powered [[Boeing 757]], but this program was subsequently cancelled. In a second program to select a replacement, the advanced [[Lockheed Martin]] Orion 21, another P-3-derived aircraft, lost out to the [[Boeing P-8 Poseidon]], a [[Boeing 737]] variant, which entered service in 2013.