The Hindenburg marked the beginning and the end of transatlantic airships. This 804-foot dirigible filled with over 7 million cubic feet of hydrogen was a crowning achievement of its age. Never before or since has a larger aircraft taken flight. However, the explosion of the Hindenburg changed the landscape for lighter-than-air crafts forever.
The Hindenburg is Engulfed in Flames
On May 6, 1937, the Hindenburg carrying 61 crew and 36 passengers arrived hours behind schedule at Lakehurst Naval Air Station in New Jersey. Inclement weather forced this delay. Buffeted by winds and rain, the craft hovered in the area by most accounts for about an hour. The presence of lightning storms were recorded. The landing of the Hindenburg with these types of conditions was against regulations. However, by the time the Hindenburg began its landing, the weather was clearing up. The Hindenburg seems to have been traveling at a fairly fast speed for its landing and for some reason, the Captain attempted a high landing, being winched to the ground from a height of about 200 feet. Soon after the mooring lines were set, some eyewitnesses reported a blue glow on top of the Hindenburg followed by a flame towards the tail section of the craft. The flame was almost simultaneously succeeded by an explosion that quickly engulfed the craft causing it to crash into the ground killing 36 people. Spectators watched in horror as passengers and crew were burned alive or jumped to their deaths. As Herb Morrison announced for the radio, "It's burst into flames… Get out of the way, please, oh my, this is terrible… Oh, the humanity and all the passengers."
The day after this horrible tragedy occurred, the papers started speculating about the cause of the disaster. Up until this incident, the German Zeppelins had been safe and highly successful. Many theories were talked about and investigated: sabotage, mechanical failure, hydrogen explosions, lightning or even the possibility that it was shot from the sky.
On the next page, discover the major theories of what happened on this fateful day in May.
The Commerce Department and the Navy led the investigations into the Hindenburg disaster. However, the Federal Bureau of Investigation also looked into the matter even though it technically had no jurisdiction. President FDR had asked all governmental agencies to cooperate in the investigation. The FBI files released about the incident through the Freedom of Information Act are available online. You must download Adobe Acrobat to read the files.
Theories of Sabotage
The theories of sabotage began to surface immediately. People believed that maybe the Hindenburg had been sabotaged to harm Hitler's Nazi regime. The sabotage theories centered on a bomb of some sort being placed aboard the Hindenburg and later detonated or some other sort of sabotage performed by someone on board. Commander Rosendahl of the Department of Commerce believed that sabotage was the culprit. (See p. 98 of Part I of the FBI documents.) According to a Memorandum to the Director of the FBI dated May 11, 1937, when Captain Anton Wittemann, the third in command of the Hindenburg, was questioned after the tragedy he said that Captain Max Pruss, Captain Ernst Lehmann and he had been warned of a possible incident. He was told by the FBI Special Agents not to speak of the warning to anyone. (See p. 80 of Part I of the FBI documents.) There is no indication that his claims were ever looked into, and no other evidence arose to support the idea of sabotage.
Possible Mechanical Failure
Some people pointed to a possible mechanical failure. Many of the ground crew later interviewed in the investigation indicated that the Hindenburg was coming in too fast. They believed that the airship was thrown into a full reverse to slow the craft. (See p. 43 of Part I of the FBI documents.) The speculation arose that this may have caused a mechanical failure which sparked a fire causing the hydrogen to explode. This theory is supported by the fire at the tail section of the craft but not much else. The Zeppelins had a great track record, and there is little other evidence to support this speculation.
Was It Shot From the Sky?
The next theory, and probably the most outlandish, involves the dirigible being shot from the sky. The investigation focused on reports of a pair of tracks found near the back of the airfield in a restricted area. However, there were numerous people on hand to watch the amazing event of the Hindenburg landing so these footprints could have been made by anyone. In fact, the Navy had caught a couple of boys who had sneaked into the airfield from that direction. There were also reports of farmers shooting at other dirigibles because they passed over their farms. Some people even claimed that joy seekers shot down the Hindenburg. (See p. 80 of Part I of the FBI documents.) Most people dismissed these accusations as nonsense, and the formal investigation never substantiated the theory that the Hindenburg was shot from the sky.
Hydrogen and the Hindenburg Explosion
The theory that gained the most popularity and became the most widely accepted involved the hydrogen on the Hindenburg. Hydrogen is a highly flammable gas, and most people believed that something caused the hydrogen to spark, thus causing the explosion and fire. At the beginning of the investigation, the idea arose that the drop lines carried static electricity back up to the airship which caused the explosion. However, the chief of the ground crew denied this claim by the fact that the mooring lines were not conductors of static electricity. (See p. 39 of Part I of the FBI documents.) More credible was the idea that the blue arc seen at the tail of the airship just before it burst into flames was lightning and caused the detonation of the hydrogen. This theory was substantiated by the presence of the lightning storms reported in the area.
The hydrogen explosion theory became accepted as the reason for the explosion and led to the end of commercial lighter-than-air flight and the stalling of hydrogen as a reliable fuel. Many people pointed to the flammability of the hydrogen and questioned why helium was not used in the craft. It is interesting to note that a similar event happened to a helium dirigible the year before. So what really caused the end of the Hindenburg?
Addison Bain, a retired NASA engineer and hydrogen expert, believes he has the correct answer. He states that while hydrogen might have contributed to the fire, it was not the culprit. To prove this, he points to several pieces of evidence:
- The Hindenburg did not explode but burned in numerous directions.
- The airship remained afloat for several seconds after the fire began. Some people report it did not crash for 32 seconds.
- Fabric pieces fell to the ground on fire.
- The fire was not characteristic of a hydrogen fire. In fact, hydrogen makes no visible flames.
- There were no reported leaks; the hydrogen was laced with garlic to give off an odor for easy detection.
After years of exhaustive traveling and research, Bain uncovered what he believes is the answer to the Hindenburg mystery. His research shows that the Hindenburg's skin was covered with the extremely flammable cellulose nitrate or cellulose acetate, added to help with rigidity and aerodynamics. The skin was also coated with flecks of aluminum, a component of rocket fuel, to reflect sunlight and keep the hydrogen from heating and expanding. It had the further benefit of combating wear and tear from the elements. Bain claims these substances, although necessary at the time of construction, directly led to the disaster of the Hindenburg. The substances caught fire from an electric spark that caused the skin to burn. At this point, the hydrogen became the fuel to the already existing fire. Therefore, the real culprit was the skin of the dirigible. The ironic point to this story is that the German Zeppelin makers knew this back in 1937. A handwritten letter in the Zeppelin Archive states, "The actual cause of the fire was the extreme easy flammability of the covering material brought about by discharges of an electrostatic nature."