Editing LZ 129 Hindenburg (section)

==Final flight: May 3–6, 1937==
{{Main|Hindenburg disaster|l1=Hindenburg disaster}}
[[File:Live audio recording from the scene of the Hindenburg disaster 1937-05-06 19-25 EST.oga|Live radio broadcast]]

After making the first South American flight of the 1937 season in late March, ''Hindenburg'' left Frankfurt for Lakehurst on the evening of 3 May, on its first scheduled round trip between Europe and North America that season. Although strong [[Headwind and tailwind|headwinds]] slowed the crossing, the flight had otherwise proceeded routinely as it approached for a landing three days later.<ref name=Aerospace>{{cite web |url= http://www.aerospaceweb.org/question/investigations/q0277.shtml |title= Cause of the ''Hindenburg'' Disaster |website= Aero Space web |access-date= January 11, 2010 |date= June 18, 2006 |first= Joe |last= Yoon }}</ref>

''Hindenburg''{{'}}s arrival on 6 May was delayed for several hours to avoid a line of thunderstorms passing over Lakehurst, but around 7:00&nbsp;pm the airship was cleared for its final approach to the Naval Air Station, which it made at an altitude of {{cvt|200|m}} with Captain [[Max Pruss]] in command.<!--not unless he was actually steering her himself...--> At 7:21&nbsp;pm a pair of landing lines were dropped from the nose of the ship and were grabbed hold of by ground handlers. Four minutes later, at 7:25&nbsp;pm  ''Hindenburg'' burst into flames and dropped to the ground in a little over half a minute. Of the 36 passengers and 61 crew aboard, 13 passengers<ref>[http://www.airships.net/hindenburg/disaster/hindenburg-passenger-list ''Hindenburg'' Disaster Passenger List] Airships.net</ref> and 22 crew<ref>[http://www.airships.net/hindenburg/disaster/crew-list ''Hindenburg'' Disaster – List of Officers and Crew] Airships.net</ref> died, as well as one member of the ground crew, a total of 36 lives lost.<ref>Thompson, Craig. "Airship Like a Giant Torch On Darkening Jersey Field: Routine Landing Converted Into Hysterical Scene in Moment's Time—Witnesses Tell of 'Blinding Flash' From Zeppelin." ''The New York Times'', May 7, 1937.</ref><ref>[http://www.airships.net/hindenburg/disaster "The ''Hindenburg'' Disaster."] Airships.net. Retrieved October 27, 2010.</ref><ref>Morrison, Herbert. [http://www.otr.com/hindenburg.shtml Live radio account of arrival and crash of ''Hindenburg''.] ''Radio Days'' via OTR.com. Retrieved October 27, 2010.</ref> [[Herbert Morrison (announcer)|Herbert Morrison]]'s commentary of the incident became a classic of audio history.

The exact location of the initial fire, its source of ignition, and the source of fuel remain subjects of debate. The cause of the accident has never been determined conclusively, although many hypotheses have been proposed. [[Sabotage]] theories notwithstanding, one hypothesis often put forth involves a combination of gas leakage and atmospheric static conditions. Manually controlled and automatic valves for releasing hydrogen were located partway up one-meter diameter ventilation shafts that ran vertically through the airship.<ref>Air Commerce Bulletin of August 15, 1937 (vol. 9, no. 2) published by the United States Department of Commerce</ref> Hydrogen released into a shaft, whether intentionally or because of a stuck valve, would have mixed with air already in the {{nowrap|shaft{{tsp}}{{mdash}}{{tsp}}}}potentially in an explosive ratio. Alternatively, a gas cell could have been ruptured by the breaking of a structural tension wire causing a mixing of hydrogen with air.<ref>"The Hindenburg Accident. A Comparative Digest of the Investigations and Findings With the American and Translated German Reports Included." R.W. Knight, Acting Chief, Air Transport Section. U.S. Department of Commerce, Bureau of Air Commerce, Safety and Planning Division, Report No. 11, August 1938.</ref> The high [[Static electricity|static charge]] collected from flying within stormy conditions and inadequate grounding of the outer envelope to the frame could have ignited any resulting gas-air mixture at the top of the airship.<ref>Report of the German Investigation Commission about the Accident of the Airship "Hindenburg" on May 6, 1937, at Lakehurst, U.S.A.</ref> In support of the hypothesis that hydrogen was leaking from the aft portion of the ''Hindenburg'' prior to the conflagration, water [[ballast]] was released at the rear of the airship and six crew members were dispatched to the [[Bow (watercraft)|bow]] to keep the craft level. 

Another more recent theory involves the airship's outer covering. The silvery cloth covering contained material with [[cellulose nitrate]], which is highly flammable.<ref>{{cite web |url=http://www.hydrogenus.com/advocate/ad22zepp.htm |title=Hydrogen Exonerated in Hindenburg Disaster |publisher=[[National Hydrogen Association]]|year=1997 |access-date=January 11, 2010 |author=Bokow, Jacquelyn Cochran |archive-url=https://web.archive.org/web/20100113191439/http://www.hydrogenus.com/advocate/ad22zepp.htm |archive-date=January 13, 2010 |quote=The NHA's mission is to foster the development of hydrogen technologies and their utilization in industrial, commercial, and consumer applications and promote the role of hydrogen in the energy field. |url-status=dead}}</ref> This theory is controversial and has been rejected by other researchers<ref name="Dessler">{{cite web|url=http://spot.colorado.edu/~dziadeck/zf/LZ129fire.pdf|title=The Hindenburg Hydrogen Fire: Fatal Flaws in the Addison Bain Incendiary-Paint Theory|author=Dessler, A. J.|date=June 3, 2004|publisher=John Dziadecki, Libraries Webmaster, University of Colorado, Boulder|access-date=January 13, 2012}}<!-- For use in the future if needed: archiveurl=https://www.webcitation.org/64fiSl1HD?url=http://spot.colorado.edu/~dziadeck/zf/LZ129fire.pdf archivedate=2012-01-13 --></ref> because the outer skin burns too slowly to account for the rapid flame propagation<ref name=Aerospace/> and gaps in the fire correspond with internal gas cell divisions, which would not be visible if the fire had spread across the skin first.<ref name="Dessler"/> Hydrogen fires had previously destroyed many other airships.<ref name="airships.net">{{cite web |url=http://www.airships.net/hydrogen-airship-accidents |title=Hydrogen Airship Disasters |publisher=airships.net |date=October 2010 |access-date=January 13, 2012 |author=Grossman, Dan}}</ref>

The [[duralumin]] framework of ''Hindenburg'' was salvaged and shipped back to Germany. There the scrap was recycled and used in the construction of military aircraft for the ''[[Luftwaffe]]'', as were the frames of [[LZ 127 Graf Zeppelin|''Graf Zeppelin'']] and [[LZ 130 Graf Zeppelin II|''Graf Zeppelin II'']] when they were scrapped in 1940.<ref>Mooney 1972, p. 262.</ref>

<gallery widths="200px" heights="160px">
File:Hindenburg Lakehurst Mail.jpg|A partially burned piece of mail from the ''Hindenburg''{{'}}s last flight
File:Hindenburg burning.jpg|''Hindenburg'' on fire
File:DLZ129 spar.jpg|A fire-scorched duralumin ''Hindenburg'' [[cross brace]] salvaged from the crash site
</gallery>