The Official Story
LZ 129 HINDENBURG
LZ 129 Hindenburg (Luftschiff Zeppelin #129; Registration: D-LZ 129) was a German commercial passenger-carrying rigid airship, the lead ship of the Hindenburg class, the longest class of flying machine and the largest airship by envelope volume. It was designed and built by the Zeppelin Company (Luftschiffbau Zeppelin GmbH) on the shores of Lake Constance in Friedrichshafen, Germany, and was operated by the German Zeppelin Airline Company (Deutsche Zeppelin-Reederei). It was named after Field Marshal Paul von Hindenburg, who was President of Germany from 1925 until his death in 1934.
The airship flew from March 1936 until it was destroyed by fire 14 months later on May 6, 1937, while attempting to land at Lakehurst Naval Air Station in Manchester Township, New Jersey, at the end of the first North American transatlantic journey of her second season of service. This was the last of the great airship disasters; it was preceded by the crashes of the British R38, the US airship Roma, the French Dixmude, the British R101, and the USS Akron.
Final Flight (May 3–6, 1937)
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 headwinds slowed the crossing, the flight had otherwise proceeded routinely as she approached for a landing three days later.
Hindenburg‘s arrival on 6 May was delayed for several hours to avoid a line of thunderstorms passing over Lakehurst, but around 7:00 pm the airship was cleared for its final approach to the Naval Air Station, which she made at an altitude of 200 m (660 ft) with Captain Max Pruss in command. At 7:21 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 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 and 22 crew died, as well as one member of the ground crew, a total of 36 lives lost. 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. Hydrogen released into a shaft, whether intentionally or because of a stuck valve, mixes with air already in the shaft – 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. The high 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. 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 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. This theory is controversial and has been rejected by other researchers because the outer skin burns too slowly to account for the rapid flame propagation 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. Hydrogen fires had previously destroyed many other airships.
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 Graf Zeppelin and Graf Zeppelin II when they were scrapped in 1940.