LZ 129 Hindenburg

"The Hindenburg" redirects here. For the film, see The Hindenburg (film); for other uses, see Hindenburg.

LZ 129 Hindenburg was a big German zeppelin. Along with its sister-ship LZ 130 Graf Zeppelin II, it was the largest aircraft ever built. During its second year of service, it was destroyed by a fire while landing at Lakehurst Naval Air Station in Manchester Township, New Jersey, USA, on May 6, 1937. Thirty-six people died in the accident, which was widely reported by film, photographic, and radio media.

The Hindenburg was named after Paul von Hindenburg (1847-1934), the President of Germany (1925–1934).

First year of service

During its first year of commercial operation in 1936, the Hindenburg flew 308,323 km (191,583 miles) carrying 2,798 passengers and 160 tons of freight and mail. It made 17 round trips across the Atlantic Ocean, with 10 trips to the US and seven to Brazil. In July of that year it also completed a record Atlantic double-crossing in five days, 19 hours and 51 minutes. The German boxer Max Schmeling returned home on the Hindenburg to a hero's welcome in Frankfurt, after defeating Joe Louis.

On August 1 the Hindenburg was present at the opening ceremonies of the 1936 Summer Olympics in Berlin, Germany. Moments before the arrival of Adolf Hitler, the airship crossed over the Olympic stadium, trailing the Olympic flag from its gondola.

During its first year of service, the airship had a special aluminium Blüthner grand piano placed on board in the music salon. It was the first piano ever placed in flight and helped host the first radio broadcast "air concert." The piano was removed after the first year to save weight.

The Hindenburg's success encouraged the Luftschiffbau Zeppelin Company to plan the expansion of its airship fleet and transatlantic services.

During the winter of 1936–37, several changes were made. The greater lift capacity allowed 10 passenger cabins to be added, nine with two beds and one with four beds, increasing the total passenger capacity to 72.

Last flight

On the night of May 3, 1937, the Hindenburg left Frankfurt, Germany for Lakehurst, New Jersey. This was the first trip of the year to Lakehurst, but the ship did fly to Rio de Janeiro earlier that year.

The crossing was uneventful, except for strong headwinds. The ship was half full, with 36 passengers and 61 crew members (21 more than usual who were crewmembers in training), but the return flight was fully booked by people attending the coronation of King George VI of the United Kingdom, which would take place on May 12, at Westminster Abbey, London.

Low number of passengers was probably because of concerns of a bomb on board. A letter was sent to the German Ambassador predicting that the ship would be destroyed by a bomb after flying over New York City.

On May 6, the ship arrived in America. The ship was already late, and the landing was further delayed because of bad weather. Captain Max Pruss took passengers on a tour through New York City, and the seasides of Boston and New Jersey.

Finally, around 7:00 p.m. local time, altitude 650 feet, the Hindenburg approached the Lakehurst Naval Air Station. This landing was different, known as a high landing or flying moor, because the ship was winched down from a higher altitude. This type of landing maneuver would save the number of ground crew, but would require more time. At 7:08 the ship made a sharp full-speed left turn to the west around the landing field because the ground crew were not ready yet. At 7:11 the ship turned back toward the landing field and valved gas. All engines idled ahead and the ship began to slow. At 7:14, and altitude 394 feet, Captain Pruss ordered aft engines full astern to try to brake the ship. At 7:17, the wind shifted direction to southwest, and Captain Pruss was forced to make a second, sweeping sharp turn, this time towards starboard. At 7:19, as the ship made the second sharp turn, 300, 300, and 500 kg of water ballast was dropped because the ship was stern heavy. Six men (three were killed in the accident) were also sent to the bow to trim the ship. None of these attempts to correct the problem worked and the ship seemed to sink even more, but Pruss was now permitted to land. At 7:21, altitude 295 feet, the mooring lines were dropped from the bow, the starboard line being dropped first. At this point, the cameramen were filming the lines being caught by the ground crew or stopped rolling altogether, and missed what was about to happen.

At 7:25, a few witnesses had seen the fabric ahead of the upper fin flutter as if gas was leaking. At the same time another witness saw what looked like static electricity moving up the hull from the bottom.

Just immediately after this, witnesses started to report a small flame ahead of the upper fin. Commander Rosendahl testified it being "mushroom-shaped" and knew at once was that the ship was doomed. One witness on the starboard side reported a fire beginning lower and behind the rudder on that side (however this may have happened after the initial fire on the port side).

Disaster

The Hindenburg, moments after catching fire.

At 7:25 p.m. local time, the Hindenburg caught fire and quickly became engulfed in bad ongoing or maybe simple flames. Where the fire started is controversial; witnesses on the port side saw yellow/red flames first just forward of the top fin, around the vent of cell 4. One, with views of the starboard side, saw flames beginning lower and farther aft, near cell 1. No. 2 Helmsman Helmut Lau also testified seeing the flames spreading from cell 4 into starboard. Wherever it started, the flames quickly spread forward. Almost instantly, a water tank and a fuel tank burst out of the hull, as seen in the picture on the right. At the same time a crack appeared behind the passenger decks. The ship's back broke, and the section from the nose to the aft engine cars lurched upwards, while the stern stayed in trim. As the Hindenburg's tail crashed into the ground, a burst of flame came out of the nose, killing three of the six crew members in the bow. As the ship kept falling with the bow facing upwards (because there was more lifting gas still in the nose), part of the port side directly behind the passenger deck collapsed inward (where the "dent" was), and the gas cell there exploded, erasing the scarlet lettering "Hindenburg" while the ship's bow lowered. One careful analysis of the flame spread, by Addison Bain of NASA, gives the flame front spread rate across the fabric skin as about 49 ft/s. The ship's gondola wheel touched the ground, causing the ship to bounce up once more. At this point, most of the fabric had burned away. At last, the ship went crashing on the ground, bow first.

The time it took for the ship to be completely destroyed has been disputed. Some believe it took 34 seconds, though others say it took 32 or 37 seconds.

The incident is widely remembered as one of the most dramatic accidents of modern time. The cause of the accident has never been determined, although many theories, some highly controversial, have been proposed.

Historic newsreel coverage

The disaster is well recorded because of an extraordinary amount of newsreel coverage and photographs, as well as Herbert Morrison's recorded, on-the-scene, eyewitness radio report from the landing field. Heavy publicity about the first transatlantic passenger flight of the year by Zeppelin to the US attracted a large number of journalists to the landing. (The ship had already made one round trip from Germany to Brazil that year.) Morrison's recording was not broadcast until the next day. Parts of his report were later dubbed onto the newsreel footage, giving the impression to many modern viewers, more accustomed to live television reporting, that the words and film were recorded together intentionally. Morrison's broadcast remains one of the most famous in history. His plaintive words, "Oh, the humanity!" resonate with the impact of the disaster. Part of its poignancy is due to its being recorded slightly fast; when corrected, his account is less frantic sounding, though still impassioned.

Morrison's famous words should be understood in the context of the broadcast, in which he had repeatedly referred to the large ground crew engaged in landing the airship as a "mass of humanity." He used the phrase when it became clear that the burning wreckage was going to settle onto the ground and that the people underneath would probably not have time to escape it. There is some speculation that his actual words were "All the humanity" — the radio recording is unclear — but it was most likely "Oh, the humanity." The complete sentence is "Oh, the humanity and all the passengers..."

Spectacular movie footage and Morrison's passionate recording of the Hindenburg fire shattered public and industry faith in airships and marked the end of the giant, passenger-carrying dirigibles. Also contributing to the Zeppelins' downfall was the arrival of international passenger aeroplane travel and Pan American Airlines. Planes regularly crossed the Atlantic and Pacific oceans much faster than the 130 km/h (80 mph) of the Hindenburg. The one advantage that the Hindenburg had over aeroplanes was the comfort it afforded its passengers, much like that of an ocean liner.

Incredibly, despite there being four newsreel cameramen and one spectator filming at the time of the fire, none of the five film cameras were rolling at the moment the ship caught fire. The four newsreel cameras were aiming at the ground crew, possibly expecting ground crewmen to be pulled off the ground as had happened to the USS Akron on May 10, 1932, with two men falling to their deaths.

There had been a series of other airship accidents, none of them Zeppelins, prior to the Hindenburg fire. Many were caused by bad weather, and most of these accidents were dirigibles of British or U.S. manufacture. Both nations' techniques for dirigible manufacture were primitive compared to the expertise of the Germans. Zeppelins had had an impeccable safety record. The Graf Zeppelin had flown safely for more than 1.6 million km (1 million miles), including the first circumnavigation of the globe. The Zeppelin company prominently featured the fact that no passenger had been injured on one of their airships.

Death toll

Despite the violent fire, most of the crew and passengers survived. Of the 36 passengers and 61 crew, 13 passengers and 22 crew died. Also killed was one member of the ground crew, Navy Linesman Allen Hagaman. The two dogs on board the ship also died. Most deaths were not caused directly by the fire but were from jumping from the burning ship. Those passengers who rode the ship on its descent to the ground survived. Some deaths of crew members occurred because they wanted to save people on board the ship. In comparison, almost twice as many perished when the helium-filled USS Akron crashed.

Survival mostly depended upon luck. Werner Franz, the fourteen year-old cabin boy had been saved from the fire by a shower of water. A water ballast tank burst open, and he was soaked. He then made his way to the hatch and turned around and ran the other way, because the flames were being pushed by the wind towards the starboard side. Franz is one of the two people aboard who are still alive as of 2007. When the control car crashed on the ground, the officers had ran, but became separated. First Officer Captain Albert Sammt found Captain Max Pruss rescuing passengers, Pruss's face was badly burned, but he would survive.

Captain Ernst Lehmann survived the crash, but though his burns were not as severe as that of Pruss, he seemed to have lost his will to live. He died the next day.

When the passenger Joseph Spah had seen the first sign of trouble he smashed the window with his movie camera (the film survived the disaster) and hung onto a nearby landing line (a parody to his stage acts) and jumped down when the ship was closer to the ground. Though he broke his ankle, he survived. His dog Ulla, one of the two dogs on board during the flight, died in the fire.

Of the six people in the bow of the ship, three of them survived, the flames shot through the nose like a blowtorch and the ship tilted upwards. Most of the people had fallen into the fire but the three hung on tight.

The four crew members in the tail fin had all survived; they were closest to the origin of the fire but escaped when the tail hit the ground.

Cause of ignition

Sabotage theory

At the time of the disaster, sabotage was commonly put forward as the cause of the fire, in particular by Hugo Eckener, former head of the Zeppelin company and the "old man" of German airships. (Eckener later publicly endorsed the static spark theory — see below.)

Another proponent of the sabotage hypothesis was Max Pruss, commander of the Hindenburg throughout the airship's career. Pruss flew on nearly every flight of the Graf Zeppelin until the Hindenburg was ready. In a 1960 interview conducted by Kenneth Leish for Columbia University's Oral History Research Office, Pruss said early dirigible travel was safe, and therefore he strongly believed that sabotage was to blame. He stated that on trips to South America, which was a popular destination for German tourists, both airships passed through thunderstorms and were struck by lightning but remained unharmed.

In 1962, A. Hoehling published Who Destroyed the Hindenburg?, a book that rejects all theories but sabotage. It even names the likely saboteur -- Eric Spehl, a rigger on the Hindenburg who died in the fire. Ten years later, Michael MacDonald Mooney's book, The Hindenburg, also identified Spehl as the saboteur. Mooney's book was made into the movie The Hindenburg, whose producers were sued by Hoehling for plagiarism, but Hoehling lost.

Those putting Spehl forward as a saboteur cite:

• His girlfriend's anti-Nazi connections; she reportedly was a communist.
• The fire's origin near Gas Cell 4, Spehl's duty station.
• Rumours that in 1938 the Gestapo was investigating Spehl's involvement.
• Spehl's interest in amateur photography, making him familiar with flashbulbs that could have served as an igniter. A dry-cell battery that might have powered a flashbulb was found in the wreckage.
• A flash or a bright reflection that crew members near the lower fin had seen just before the fire.

Since it is very unlikely that Spehl wanted to kill people, proponents of this sabotage theory say that he wanted the ship to explode after the landing (already over 12 hours late) but was too busy to reset the bomb.

During the landing maneuver, rigger Hans Freund dropped a landing line in front of the lower fin. The line became caught in the bracing wires of the ship, so No. 2 helmsman Helmut Lau climbed up from the lower fin to release it. When both men looked up toward the front of the ship, they were surprised by what they saw.

Freund described a flash like a flashbulb's, and Lau said he saw a brilliant reflection between cells 4 and 5. They then heard a muffled detonation and a thud as the Hindenburg's back broke. Some believe that this is evidence for sabotage. Others believe Freund was actually looking rearward, away from cells 4 and 5, but that Rudolf Sauter, another crew member in the lower fin had seen the flash.

Another suspect was a passenger, a German acrobat named Joseph Spah, who survived the fire. He brought with him a dog, a German shepherd named Ulla, as a surprise for his children. (Ulla did not survive.) He often made unaccompanied visits to the stern to feed, talk, and play with the dog. Some, noting that Spah told many anti-Nazi jokes, and that he was an acrobat who could climb into the ship's rigging, accuse him of planting a bomb when he was with his dog.

It has even been suggested that Adolf Hitler himself ordered the Hindenburg to be destroyed in retaliation for Eckener's anti-Nazi opinions.

However, opponents of the sabotage hypothesis argued that only speculation supported sabotage as a cause of the fire, and no credible evidence of sabotage was produced at any of the formal hearings.

Spehl died in the fire and was unable to refute the accusations. The FBI investigated Spah and reported finding no significant evidence of sabotage.

Neither the German nor the American investigation endorsed any of the sabotage theories. Proponents of the sabotage theory argue that any finding of sabotage would have been an embarrassment for the Nazi regime, and they speculate that such a finding by the German investigation was suppressed for political reasons.

Eckener believed that the reason why Pruss, Lehmann, and Rosendahl all supported sabotage was because they may have felt guilty for their acts. Pruss made the sharp turn, Lehmann pressured Pruss to make it, and Rosendahl called the ship in..

Static spark theory

Another theory posits that the fire was started by a spark caused by a buildup of static electricity on the airship. Whether the spark ignited hydrogen or the outer skin has been disputed.

Proponents of the static spark theory point out that the airship's skin was not constructed in a way that allowed its charge to be evenly distributed throughout the craft. The skin was separated from the duralumin frame by non-conductive ramie cords, in effect electrically insulating the skin from the frame and allowing a difference in potential to form between them.

In order to make up for a delay of more than 12 hours in its transatlantic flight, the Hindenburg passed through a weather front of high humidity and high electrical charge. This made the airship's mooring lines wet and thus conductive and may have given its skin an electrical charge. When the wet mooring lines, which were connected to the frame, touched the ground, they would have grounded the frame but not the skin. That could have caused a sudden potential difference between skin and frame and set off an electrical discharge -- a spark.

A variant of this theory which also plays an important part in the hydrogen theory (see below) was presented by Dr. Eckener. He was confused that the ship didn't catch fire when the ropes were first dropped. He believed that when the ropes were first dropped they were dry but slowly got dampened in the four minutes from the first rope dropped to the fire. There would be a sudden potential difference the ship itself and the overlying air masses. The Hindenburg would have acted as a giant kite close to the storm clouds. However, Eckener believed the spark ignited leaking hydrogen instead.

Some witnesses reported seeing a glow consistent with St. Elmo's fire along the tail portion of the ship just before the flames broke out, but these reports were made after the official inquiries were completed.

The Hindenburg had a cotton skin covered with a finish known as "dope". It is a common term for a plasticised lacquer that provides stiffness, protection, and a lightweight, airtight seal to woven fabrics. In its liquid forms, dope is highly flammable, but the flammability of dry dope depends upon its base constituents, with butarate dope being far less flammable than cellulose nitrate, for example. When the mooring line touched the ground, a resulting spark could have ignited the dope in the skin.

Harold G. Dick was Goodyear Zeppelin's representative with Luftschiffbau Zeppelin during the mid-1930s. He flew on test flights of the Hindenburg and its sister ship, the Graf Zeppelin II. He also flew on numerous flights in the original Graf Zeppelin and ten round-trip crossings of the north and south Atlantic in the Hindenburg. In his book The Golden Age of the Great Passenger Airships Graf Zeppelin & Hindenburg, he observes:

In addition to Dick's observations is the fact that during the Graf Zeppelin II's early test flights, measurements were taken of the airship's static charge. It is clear that Dr. Ludwig Durr and the other engineers at Luftshiffbau Zeppelin took the static discharge theory seriously and considered the insulation of the fabric from the frame to be a design flaw in the Hindenburg.

A variant of the static spark theory, presented by Addison Bain, is that a spark between inadequately grounded fabric cover segments of the Hindenburg itself started the fire.

Lightning theory

A. J. Dessler, former director of the Space Science Laboratory at NASA's Marshall Space Flight Center and a critic of the incendiary paint theory (see below), favors a much simpler explanation for the conflagration: natural lightning. Like many other aircraft, the Hindenburg had been struck by lightning several times. This does not normally ignite a fire in hydrogen-filled airships, because the hydrogen is not mixed with oxygen. However, many fires started when lightning struck airships as they were venting hydrogen in preparation for landing, as the Hindenburg was doing at the time of the disaster. The vented hydrogen is mixed with air, making it readily combustible. Dessler cites an airship rule from the time: "Never blow off gas during a thunderstorm."

However, Dr. Eckener believed that the way the fire appeared was not consistent with that of a fire caused by lightning. Witnesses described the fire appearing in a wave motion. Eckener believed that the shape of the fire was consistent with that of a static spark. .

Engine exhaust sparks theory

On the 70th anniversary of the accident, The Philadelphia Inquirer carried an article with yet another theory, based on an interview of ground crew member Robert Buchanan. He had been a young man on the crew manning the mooring lines.

The excessively stormy day had not only delayed the dirigible's arrival but also soaked him and many of the other mooring crew. As the airship was approaching the mooring mast, he noted that one of the engines, thrown into reverse for a hard turn, backfired, and a shower of sparks was emitted. He and others think that this was the trigger that ignited the craft, not static electricity, as the official version goes.

When the Hindenburg ignited, instead of an explosion there were just three sequential plumes of flame on the outer shell. The cotton cover with its coating, was quite flammable, and the heat and sparks from the backfiring engine may have been the ignition source.

However, it is unknown if sparks could ignite the doping compound, and Dr. Eckener rejected that hydrogen could be ignited when the theory was mentioned at an unofficial inquiry at night. This was a chat with crew members. He believed that the hydrogen could not have been ignited by any exhaust because the temperature is too low to ignite the hydrogen. The ignition temperature for hydrogen is 700°C, but the sparks from the exhaust only reach 250°C.

Fire's initial fuel

Most current analysis of the fire assumes that ignition due to some form of electricity was the cause. However, there is still controversy over whether the fabric covering of the ship or the hydrogen used for buoyancy was the initial fuel for the fire.

The incendiary paint theory

The incendiary paint theory asserts that the major component in the fire was the skin because of the doping compound used on it.

Proponents point out that the coatings on the fabric contained both iron oxide and aluminum-impregnated cellulose acetate butyrate (CAB). These components are potentially reactive, even after fully setting. In fact, iron oxide and aluminum are sometimes used as components of solid rocket fuel or thermite. The propellant for the Space Shuttle solid rocket booster includes "aluminum (fuel, 16%), (and) iron oxide (a catalyst, 0.4%)."

Addison Bain received permission from the German government to search its archives and discovered that during the Nazi regime, German scientists concluded that the dope on the Hindenburg's fabric skin was the cause of the conflagration. Bain interviewed the wife of the investigation's lead scientist, and she confirmed that her husband had told her about the conclusion and instructed her to tell no one, presumably because it would have embarrassed the Nazi government.

The paint theory is limited to the source of ignition and to the flame front propagation, not to the source of most of the burning material as that was clearly the hydrogen.

Critics point out that port side witnesses on the field, as well as crew members stationed in the stern, saw a glow inside Cell 4 before any fire broke out of the skin, indicating that the fire began inside the ship (or that it was a hydrogen fire feeding on the whole cell). Newsreel footage supports this. Proponents of the paint theory claim that the glow can be explained. They claim that what witnesses saw was the fire on the starboard side (another proponent claims that a witness saw the fire start from the starboard side) through the structure, looking like a glow. However, photographs of the early stages of the fire show the gas cells of the Hindenburg's entire aft section fully aflame. Burning gas spewing upward from the top of the ship was causing low pressure inside, allowing atmospheric pressure to press the skin inwards. It should also be noted that not all fabric on the Hindenburg burned. The fabric on several of the tail structures was not completely consumed. That the fabric not near the hydrogen fire extinguished itself is not consistent with the 'explosive' dope theory.

The hydrogen theory

Those who believe hydrogen was the initial fuel discount arguments for the incendiary paint theory as not credible. They point out that cellulose acetate butyrate (CAB) varnish is rated within the plastics industry as combustible but nonflammable. That is, it will burn when placed in a fire but is not readily ignited by itself. In fact, it is considered to be self-extinguishing. That many pieces of the Hindenburg's skin survived despite such a fierce fire is cited as proof. In his experiment, Addison Bain used a high-energy ignition source (a spark) to make it burn.

While aluminum and iron oxide components of the fabric doping compounds are potentially reactive, they were in incorrect proportions, were applied on only one part of the airship, and were separated by a layer of CAB that would have prevented their mingling and reacting.

Proponents of the incendiary paint theory argue that the airship's nose remained airborne for a while because the hydrogen cells were intact, but proponents of the hydrogen theory contend that the nose stayed airborne due to the effects of buoyancy forces and the inertia of the ship's considerable mass. They point to pictures that show the fire burning along straight lines coinciding with the boundaries of gas cells. This suggests that the fire was not burning along the skin, which was continuous. Crew members stationed in the stern reported actually seeing the cells burning.

Although the hydrogen was odorised with garlic, nobody reported smelling the odor. Odorised hydrogen would have been detected only in the area of a leak. The fire started near the top of the airship far from any crew or passengers. Once the fire was underway, more powerful smells would have masked any garlic odor. There is however, no official document that the hydrogen was even odorised.

Support that any leak happened was that the ship remained stern heavy for the last few minutes. Though Pruss believed that this stern heaviness was normal, attempts to correct it had failed and the ship seemed to get even heavier after the second and last sharp turn. This suggests a massive leak of gas occurred and it started to fill up the space in between the outer skin and the cells.

How gas could have leaked remains debatable. Many believe it was that a bracing wire cracked (see below), while others believe that a vent was stuck open and gas leaked through the vent. During a trip to Rio a gas cell was nearly emptied when a vent stuck open; gas had to be transferred from other cells..

Puncture theory

A variant of the theory above cites the newsreels of the landing approach. Newsreels show the Hindenburg making sharp turns towards port, and then starboard just before bursting into flames. Some speculate that one of the many bracing wires within the airship snapped and punctured at least one of the internal gas cells. Gauges found in the wreckage showed the tension of the wires was much too high. Some of the wires may have been substandard. One bracing wire tested after the crash broke at only 70% of its rated load. A punctured cell would have freed hydrogen into the air and could have been ignited by a static discharge (see above).

It is also possible that the broken bracing wire then whipped a girder, causing sparks to ignite the leaking hydrogen..

A ground crew member, R. H. Ward, reported seeing a piece of the airship fluttering, perhaps providing an opening for a spark to reach escaping hydrogen inside the airship, or vice versa. He said that the fire began there, but that no other disturbance occurred at the time when the fabric fluttered. Another man on the top of the mooring mast had also reported seeing a flutter too. People on board the ship also reported hearing a muffled sound, and another ground crew member on the starboard side reported hearing a crack. Some speculate the sound was from a bracing wire snapping.

Advocates of this theory believe that the hydrogen began to leak approximately five minutes before the fire.

Dr. Eckener was the one to conclude that the puncture theory was the most likely cause of the disaster. After this, he believed that Captains Pruss and Lehmann, and Charles Rosendahl were to blame for the whole disaster. He believed that Lehmann told Pruss to make the sharp turn, and that Pruss and Rosendahl were concerned more about the time delay than the weather, because an unobserved storm front occurred just when the Hindenburg approached. But in his heart, he found himself to blame, for a decision 8 years earlier, which was a close secret.

Eckener concluded that the fire was caused by the ignition of hydrogen by a static spark:

I believe that the fire was not caused by an electrical spark, but by a static spark. A thunderstorm front had passed before the landing manuever. However if one observes more closely one can see that this was followed by a smaller storm front. This created conditions suitable for static sparks to occur. I believe spark had ignited gas in the rear of the ship.

It may seem strange that the fire did not occur the moment the landing ropes had touched the ground, because that is when the ship would have been earthed. I believe there is an explanation for this. When the ropes were first dropped they were very dry, and poor conductors. Slowly however they got dampened by the rain that was falling and the charge was slowly equalized. Thus the potential difference between the ship and the overlying air masses would have been sufficient enough to generate static electricity. The Hindenburg would have acted as a giant kite, close to the storm clouds, collecting a static spark.

I am convinced, that a leak must have occurred in the upper rear section of the ship. My assumption is confirmed by the remarkable observations by one of the witnesses. He described seeing a peculiar flutter as if gas was rising and escaping. If I were to be asked to explain what had caused this abnormal build-up of gas, I could only make to myself one explanation.

The ship proceeded in a sharp turn during its landing maneuver. This would have generated extremely high tension in the sections close to the stabilizing fins, which are braced by shear wires. I suspect that under such tension one of these wires may have broken and caused a rip in one of the gas cells. The gas then filled up the space between the cell and the outer cover, which is why the ship sank at the rear. This accumulated amount of gas was then ignited by a static spark. This was not lightning but a small static spark, enough to ignite free gas in the rear.

One must know that the ship actually proceeded in two sharp turns. The first turn was towards port at full speed as the ship circled the landing field. After circling the landing field, the wind shifted direction towards southwest, and a sharper turn towards starboard was ordered near the end of the landing maneuver. After the last turn the ship seemed to drop even more at the stern, though a slight stern heaviness was already noticed before this turn. One or both of these turns towards opposite directions could also have weakened the structure.

MythBusters

The Discovery Channel series MythBusters explored the incendiary paint theory (IPT) and the hydrogen theory in an episode that aired January 10, 2007. The show's hosts, Adam Savage and Jamie Hyneman, demonstrated that when set alight with a blowtorch a 1:50 scale model of the Hindenburg burnt twice as fast in the presence of diffused hydrogen as without it. A thermite reaction was observed in the burning skin which would have accelerated the fire but they concluded that hydrogen was the main fuel. The hydrogen filled model produced a fire with flames that came out of the nose and resembled the newsreel footage of the Hindenburg disaster.

The program concluded that the IPT myth was "Busted".

Rate of flame propagation

Fabric of the Hindenburg, held in the Steven F. Udvar-Hazy Center

Regardless of the source of ignition or the initial fuel for the fire, there remains the question of what caused the rapid spread of flames along the length of the ship. Here again the debate has centered on the fabric covering of the ship and the hydrogen used for buoyancy.

Proponents of the incendiary paint theory also contend that the fabric coatings were responsible for the rapid spread of the fire. They point out that the combustion of hydrogen is not usually visible in daylight, because most of its radiation is not visible. Thus what can be seen burning in the photographs cannot be hydrogen. The motion picture films show the fire spreading downward along the skin of the airship.

Proponents claim that in 1935, a helium-filled blimp with an acetate-aluminium skin burned near Point Sur in California with equal ferocity. Proponents also claim that even the USS Macon burned. Opponents point out that these two incidents had nothing to do with the dope. The small blimp burned because of a fuel leak, and the Macon burned because it was firing flares.

Those skeptical of the incendiary paint theory cite recent technical papers which claim that even if the ship had been coated with actual rocket fuel, it would have taken many hours to burn — not the 32 to 37 seconds that it actually took. Proponents claim that this criticism does not take into account the conditions that lead to firestorms, such as convection and ignition from radiant energy.

Also, while hydrogen tends to burn invisibly, the materials around it would be combustible and change the color of the fire. While fires generally tend to burn upward, including hydrogen fires, the enormous radiant heat from the blaze would have quickly spread fire over the entire surface of the ship, thus explaining the downward propagation of the flames. Also explaining the downward streaks of fire would be that falling debris would be on fire.

The most conclusive proof against the fabric theory is in the photographs of the actual accident as well as the many airships which were not doped with aluminum powder and still exploded violently. When a single gas cell explodes, it creates a shock wave and heat. The shock wave tends to rip nearby bags which then explode themselves. In the case of the Alhorn disaster during WW I, explosions of ships in one shed caused the explosions of others in sheds nearby, wiping out the ships at the base.

The photos of the Hindenburg disaster clearly show that after the cells in the aft section of the airship exploded and the combustion products were vented out the top of the ship, the fabric on the rear section was still largely intact, and air pressure from the outside was acting upon it, caving the sides of the ship inward due to the reduction of pressure caused by the venting of combustion gases out the top.

The loss of lift at the rear caused the airship to nose up and the back to break (the ship is still in one piece), at that time the primary mode of spread for the fire was along the axial gangway which acted as a chimney conducting fire which burst out the nose right when the ship's tail touched the ground, as seen in one of the most famous pictures of the disaster. As the flames burst from the nose, the fabric on most of the forward part of the airship was still intact, showing that the propagation of the fire was via hydrogen, not the fabric.

Also supporting the fact that hydrogen was burning was that a few seconds after the fire burst out the nose a fire started in the cell behind the passenger decks when the ship bent on the side due to a crack in the side just behind the passenger decks.

Modern experiments that recreated the fabric and coating materials of the Hindenburg seem to discredit the incendiary fabric theory. They conclude that it would have taken about 40 hours for the Hindenburg to burn if the fire had been driven by combustible fabric. Two additional scientific papers also strongly reject the fabric theory.

Even if the fire was started by the fabric, it would have set off the leaking hydrogen. Hydrogen would still be required to increase the burn speed of the fire, regardless of what was ignited first. If the Hindenburg was filled with helium and still burned, the fire would be slower and most people, if not all, would survive.

Other controversial hypotheses

Structural failure

Captain Pruss believed that the Hindenburg could withstand tight turns without significant damage. Others believe that the ship would have been weakened by being repeatedly stressed. Even a 10-meter, full-scale replica of the Hindenburg's passenger quarters, displayed in the Zeppelin Museum in Friedrichshafen, has developed some metal fatigue.

The ship did not receive much routine inspection, even though there was evidence of some damage on previous flights. It is not known if damage was repaired and if all the failures had been found. The Hindenburg once lost an engine and almost drifted over Africa, where it could have crashed. Dr. Eckener was furious and ordered all section chiefs to inspect the ship during flight.

In March 1936, the Graf Zeppelin and the Hindenburg made three-day flights to drop leaflets and broadcast speeches via loudspeaker. Before the ship's takeoff on March 26, 1936, Captain Lehmann chose to launch the Hindenburg with the wind blowing from behind the ship, instead of into the wind as per standard procedure. During the takeoff, the ship's tail struck the ground, and part of the lower fin was broken. Many spectators' cameras were confiscated to prevent negative publicity, but Harold G. Dick concealed his camera and took pictures of the damaged fin. Dr. Eckener was very upset and rebuked Captain Lehmann:

How could you, Herr Lehmann, order the ship to be brought out in such wind conditions. You had the best excuse in the world for postponing this idiotic flight; instead, you risk the ship, merely to avoid annoying Herr Goebbels. Do you call this showing a sense of responsibility towards our enterprise?

Though the damage was repaired, the force of the crash may have already forced up the fin and caused internal damage.

Only six days before the disaster, there was a plan assisted by the U.S. Navy to make the Hindenburg have a hook on her hull to carry aircraft in a similar way to what the Navy did with the USS Akron and the USS Macon. However, the trials were unsuccessful; the biplane had bashed the hook several times. This could have also caused an amount of damage weakening the structure.

Photographs and Newsreels of the disaster show that the stern section of the ship collapsed inward in a similar way to an eggshell. with an inward dent directly behind the passenger decks, which appeared the moment the ship burned. When the ship collapsed with the bow facing upwards, this part collapsed inward, causing another plume of fire to start. Some have suggested these two occurrences support the fact that there must have been structural failures around the entire ship.

This theory of the cause of the fire has not been very popular, because it does not explain exactly why the fire started, instead supporting the puncture theory.

Fuel leak

The 2001 documentary Hindenburg Disaster: Probable Cause suggested that 16-year-old Bobby Rutan, who said he had smelled "gasoline" when he was standing below the Hindenburg's aft port engine, had detected a diesel fuel leak. The day before the disaster a fuel pump had broken during the flight. A crew member said this was fixed but it may not have been. The resulting vapor would have been highly flammable and could have self-combusted. The film also suggested that overheating engines may have played a role.

During the investigation, Commander Charles Rosendahl dismissed the boy's report.

Critics say the documentary is misleading, because it misconstrued the statements by the crewmen in the Hindenburg's lower fin. The crewmen said they saw a flash in the axial catwalk, but the film placed the flash in the keel catwalk closer to the passenger areas.

Luger pistol among wreckage

Some more sensational newspapers at the time said that a person on board committed suicide because a Luger pistol with one shell fired was found among the wreckage.

Memorial

The actual site of the Hindenburg crash at Lakehurst Naval Air Station (re-established as Naval Air Systems Command (NAVAIR) at Naval Air Engineering Station (NAES) Lakehurst, or "Navy Lakehurst" for short ) is marked with a chain-outlined pad and bronze plaque where the airship's gondola landed. It was dedicated on May 6, 1987; the 50th anniversary of the disaster. Hangar #1, which still stands, is where the airship was to be housed after landing. It was designated a Registered National Historic Landmark in 1968. Pre-registered tours are held through the Navy Lakehurst Historical Society. Due to security concerns, no foreign nationals are permitted on the tours.

Cultural references

Audio

• The 1938 radio drama version of War of the Worlds uses the reporting of the Hindenburg disaster as inspiration for its style of reporting the Martian invasion.
• English rock group Led Zeppelin's eponymous first album has a picture of the Hindenburg disaster on the front cover. The band's name itself is a reference to Keith Moon's quotation that the band would "go over like a lead zeppelin." The album cover is in fact a pen-and-ink illustration of the famous UPI photograph drawn with a Rapidograph pen by graphic artist George Hardie.
• Folk/blues musician Huddie Ledbetter (AKA Leadbelly) wrote a two-part song about the Hindenburg crash called "The Hindenburg Disaster".
• Experimental Rock musician Captain Beefheart's 1969 album Trout Mask Replica uses the Hindenburg fire footage as inspiration for the track "The Blimp (mousetrapreplica)" on side 4 of the double album.

Film & television

• In the The Simpsons episode "Lisa the Beauty Queen", Barney is in control of the Duff Blimp (a parody of the Hindenburg) after being given permission to steer it. He makes a severe turn and the blimp explodes. Reporting on the event, anchorman Kent Brockman says, "Oh, the humanity!" before returning to a story on the Springfield grand opening of Danish superchain Shøp.
• In the The Simpsons episode "Bart the Fink", Bart's checkbook is a flip-animation of the Hindenburg exploding. The checkbook series is named "Oh the humanity."
• In the The Simpsons episode "Dog of Death", Mr. Burns and Smithers brainwash Santa's Little Helper with a movie featuring various numerous clips. One clip was an animation of the Hindenburg Disaster.
• In the Seinfeld episode "The Puerto Rican Day", George Costanza has gone to a theater to see a movie about the Hindenburg accident called Blimp. When the airship goes up in flames, he says "That's gotta hurt!" loud enough for the other moviegoers to hear. Instead of making them angry, his comment makes them laugh. He's so pleased with himself that he goes to Blimp several times just so he can make the joke.
• In "The Pothole" episode of Seinfeld, after a series of unfortunate events leads Newman to drive over a sewing machine, the sparks of which ignite paint thinner covering the highway, his mail truck becomes engulfed in flames, causing him to yell, "Oh, the humanity!"
• In the WKRP episode "Turkeys Away", live turkeys are thrown out of a helicopter for a Thanksgiving Day promotion. The turkeys, unable to fly, crash to the ground. Les Nessman, with tears in his eyes, exclaims, "Oh, the humility!" in his confused emulation of the Hindenburg radio broadcast.
• On the television series Mystery Science Theater 3000, the characters frequently say, "Oh, the humanity!" (or similar) whenever something explodes.
• In the Family Guy episode "The Cleveland-Loretta Quagmire", Peter refers to numerous aviation inventions, including the Hindenpeter, which meets its end by landing on his neighbor Joe's house and exploding.
• The Hindenburg (1975 movie) is a speculative thriller based on the events leading up to and including the disaster.
• Starting from Episode #109 of the animated MTV series Daria, the iconic picture of the Hindenburg in flames is repeatedly seen in Daria's locker.
• An episode of Mythbusters featured experiments and other tests to see what initially ignited the airship (see above).
• In an episode of The Waltons entitled "The Inferno", the news service dispatches John-Boy to Lakehurst, New Jersey, to cover the Hindenburg landing. Witnessing the disaster shakes him up badly.
• In the Wings episode "The Tennis Bum", Lowell has skillfully and painstakingly constructed a flying model blimp and forbids Joe from touching its remote control. Joe later flies it anyway, accidentally steering it around a door. Roy comes in, slams the door against the blimp, and breaks it. Looking at the destroyed blimp, Joe utters, "Oh, the humanity!"
• In Hayao Miyazaki's anime film Kiki's Delivery Service, high winds cause a blimp to catch on a building. In the English dubbed version, one of the news reporters says, "Oh, the humanity!"
• The movie The Rocketeer concludes with a final confrontation between hero and villain set in and on the Zeppelin Luxembourg, which explodes Hindenburg-style over the hills of Hollywood.
• In the film Heathers, each time the police find more dead teenagers, they say, "Oh, the humanity!"
• The film Sky Captain and the World of Tomorrow opens with the Hindenburg III approaching the Empire State Building to dock (the building was originally designed to serve this purpose).
• In Indiana Jones and the Last Crusade Indy and his father (Sean Connery) board the LZ138 Zeppelin, Indy grabs a plane and flies away (apparently the Zeppelin Company tried to install a trapeze-like hangar in the Hindenburg to hold planes with the help of the US Navy, but the project was abandoned).
• In the live-action film version of How the Grinch Stole Christmas, the Grinch drinks some alcohol and blows through a lighter to burn down the giant Christmas tree. As it blazes to ashes in the inferno, he shouts "Oh, the WHOmanity!"
• In the film Ready to Rumble, the character of Jimmy King (Oliver Platt) gets kicked in the crotch by his wife and screams, "Oh, the humanity!"
• In the "Fresh Prince of Bel-Air" episode "The Butler Did It" Will is pacing the room and when he brings up tragic events that happened in one day he says "The Hindenburg blew up in one day!".

Other

• The Hindenburg is the primary motif of the first section of Three Tales by Steve Reich and Beryl Korot.
• In the novel The Never War by D. J. MacHale, the main character can choose to keep the Hindenburg Disaster from happening, which he thought would keep World War II from starting. However, he decides not to, since he discovers that the airship is carrying German spies that would allow the Nazis to develop atomic weapons before the Allies.
• The short story "Love and Hydrogen" by Jim Shepard takes place on the Hindenburg and uses the theory that a bracing-wire bolt snapped.
• In the game Thrillville, the commentator of the RC Wars minigame may say, "Oh, the carnage," a reference to Herbert Morrison's quote.
• The last flight of the Hindenburg is a major plot element in Allen Steele's science fiction fix-up novel Chronospace (the relevant part previously published as a stand-alone novella "...Where Angels Fear to Tread", winning the Hugo Award for Best Novella in 1998). Two researchers from the future travel to 1937 and replace Mr. and Mrs. Pannes, real passengers who were killed in the disaster, and inadvertently prevent the Hindenburg from being destroyed until after the passengers and crew disembark. The novel assumes that Eric Spehl planted a flashbulb-triggered bomb in gas cell 4.
• Stephen Colbert at the 2006 White House Correspondents Association's annual dinner said, referring to President Bush's 36% approval rating, "And then you write, 'Oh, they're just rearranging the deck chairs on the Titanic.' First of all, that is a terrible metaphor. This administration is not sinking. This administration is soaring. If anything, they are rearranging the deck chairs on the Hindenburg.!"
• On the MMORPG World of Warcraft, there is one man who transports you named Hin Denburg.
• There has been a poster marketed, with the famous picture of the Hindenburg going up in flames, but with a giant manatee substituted for the actual airship. At the bottom of the poster is the phrase "Oh, the huge manatee!"

See also

• Crash cover
• Hindenburg Disaster Newsreel Footage
• Herbert Morrison (announcer)
• List of Airship Accidents
• Zeppelin
• Harold G. Dick was an American engineer who flew on most of the Hindenburg flights.
• The Zeppelin Museum Friedrichshafen displays a reconstruction of a 33 m section of the Hindenburg.
• Hindenburg: The Untold Story was a docudrama aired on the 70th anniversary of the disaster, May 6, 2007.

References

• Birchall, Frederick (August 1, 1936). "100,000 Hail Hitler; U.S. Athletes Avoid Nazi Salute to Him". The New York Times, p. 1.
• Duggan, John (2002). LZ 129 "Hindenburg" — The Complete Story. Ickenham, UK: Zeppelin Study Group. ISBN 0-9514114-8-9.
• Harold G. Dick & Douglas H. Robinson "The Golden Age of the Great Passenger Airships Graf Zeppelin & Hindenburg." Washington, D.C.: The Smithsonian Institution Press, 1985.*/+

External links

• Hindenburg: Sky Cruise Illustrated account of a flight on the Hindenburg - with maiden voyage and final flight passenger lists
• Page at Great Zeppelins website, with various pictures
• The Hindenburg in the development of zeppelins
• Hindenburg & Hydrogen
• An Article Supporting the Flammable Fabric Theory Retrieved with the Wayback Machine
• Two Articles Rejecting the Flammable Fabric Theory
• Experiments Reject the Flammable Fabric Theory
• An article supporting the engine exhaust spark theory: "The real cause of the Hindenburg disaster?" - Philadelphia Inquirer 2007-05-06 (the 70th anniversary of the Hindenburg disaster)
• FBI investigation into the Hindenburg disaster
• Harold G. Dick Airship Collection (Harold G. Dick was an American engineer who flew on most Hindenburg flights.)
• Footage from Castle and Pathé coverage of the Hindenburg disaster at Internet Archive
• "The Hindenburg" - Failure Magazine (January 2002)
• YouTube video of Herb Morrison's famous report synchronized with newsreel footage
• ZLT Zeppelin Luftschifftechnik GmbH & Co KG -- The company is still in the airship business today.
• Thirty-Two Seconds - An article about the disaster that features rare photos of the disaster, a photograph of the surviving crew and a report on Cabin Boy Werner Franz.
• What Happened to the Hindenburg? Transcript - Secrets of the Dead (June 15, 2001, PBS)
• Passenger and Crew List of the Hindenburg on its final voyage
• YouTube video: Universal Newsreel - May 10, 1937 Special report on the Hindenburg disaster.
• YouTube video: Footage of the Hindenburg over New York City, circa 1936

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