The Hindenburg & Causes of Failure
"The Titanic of the skies" they called it. The Titanic had 16 watertight compartments, the Hindenburg had 16 airtight cotton bags filled with Hydrogen. Both were colossal and exorbitant. Both were used for transatlantic trips. Both were the most exuberant ships of their era. And unfortunately, both had tragic endings.
The Hindenburg was the height and the death of the airship era. Looking back now to almost a century ago; an 804 ft compartment filled with highly flammable hydrogen sounds like a disaster waiting to happen. In Lessons Amid the Rubble Pfatteicher mentions a useful framework to describe disasters; engineered disasters, procedural disasters, and systematic disasters. The Hindenburg is a great example of how all, and not one single factor contributed to its demise.
An engineered accident; in the case of the Hindenburg had a lot to do with the design of the airship itself. Not necessarily the engineer's fault; but constraints put on them by the US Government. After the crash of R101 in France (which was a hydrogen-filled airship) in which the majority of the people died in the fire, rather than the impact itself; Heckner who built the Hindenburg attempted to use helium rather than hydrogen (Britannica BAF). However, you can imagine how tensions were overseas, only two years before a second world war would emerge. America who was responsible for supplying helium worldwide had banned its export in fear that they would use this monatomic gas as a military weapon. Forcing engineers to find other ways to make this airship float (EIC 205).
A procedural accident is described not as a design flaw but rather the misuse of the product. In the example of the Hindenburg, there was, in fact, a procedural hypothesis developed. When the Hindenburg arrived at Lakehurst NJ from the southwest. Upon arrival they noticed that the winds were actually coming from the east; the captain made a slow wide left turn to align the airship with the wind (ultimately continuously reducing and reversing the engines) Officer Sammt, who was responsible for keeping the airships in trim leveled, was working hard to reduce the buoyancy of the ship, as he noticed its tail was getting heavier (Airships Hinden. Disaster). In the midst of all this chaos, the wind had actually now shifted from the east to southwest. Now, yet again Captain Pruss had to land the ship southwesterly. The Hindenburg was already so close to the ground that they did not have the time to make a slow wide turn as they did the first time. This is when Captain Pruss decided to make a sharp turn, in order to get the airship in the intended direction. Many scientists have hypothesized that these sharp turns ultimately stressed the ship out and caused a bracing wire to snap and puncture one of the hydrogen-filled cells (Stromberg 2012).
"Systematic Accidents" are described by Professor Fleddermann as a combination of errors. Emphasizing that if any errors were to happen in isolation, it would not be a big deal (Pfatteicher pg. 71). First, let me explain how these airships landed. In order to land the Hindenburg, they had to be in close proximity to the mooring mast, they would throw down their landing ropes; almost like a ship throwing down its anchor. To make this massive airship drop it would release hydrogen gas through vents found on top of the airship. Because of the release of hydrogen, they had to make sure never to land during a storm; to prevent static electricity from igniting the gas and starting a fire. May 6th, 1937, they waited a few hours for the storm to pass in order to land the airship. Unbeknowing to them, the skin of the airship was still negatively charged due to the atmosphere. So as they threw down the wet mooring line; connected to the metal frame it acted as a conductor of electricity. The electrical charge traveling from the ground to the ship ignited the hydrogen. (Weatherbug Schools 2012) So we can conclude it is was a combination of weather, material, and misuse of this grand zeppelin that all contributed to its tragic ending.
With hydrogen being the worlds lightest element, you can imagine why they would have used it to travel. No matter where the Hindenburg flew, it caught the attention of everyone who saw this colossal ship in the sky. Today we still use airships, but not as a form of international travel, but more like an advertisement. Growing up I remember seeing the Good Year blimp floating around. It has been years since I last saw it, but I'm pretty sure its still floating somewhere out there.
Although the difference between a blimp and a zeppelin has to do with the actual structure (blimp being an inflatable compartment, while a zeppelin contained rigid compartments) they are both considered airships. And while History repeats itself, not excluding the numerous failures of hydrogen-filled airships; sometimes as humans, we have the tendency of ultimately learning from these disasters.
Modern airships today, use helium to fly. Which is safer than flying with a massive amount of flammable gas overhead. Apart from the material used, what was also needed with historic airships that is not necessary today; was the extensive ground crew that held the mooring ropes upon departure and arrival.But today the aerocrafts compresses the helium that gives it lift into smaller tanks inside the ship, letting the rest of the membrane fill with air and the ship to land more like a traditional aircraft (NBC 2013).
The ZRS-5 also known as the USS Macon was also caught in a storm in California. This failure, however, was due to maintenance as the rings and tailfins suffered damage during high elevation to clear over mountains in Arizona ten months prior (Airships.net). The airship's repairs were not complete and unfortunately was not able to withstand the storm, causing the ship to crash and sink off Monterey Bay (USS Macon Wiki).
The first American build rigid airship was the Shenandoah. The Shenandoah was actually built in Lakehurst NJ, which I found rather interesting. You would think that the weather would be the main culprit, as this aircraft was also caught in a storm as it crossed Ohio. This aircraft broke apart and crashed into a field. Reason being was that the wind caused her to rise to dangerous altitudes and the helium bags popped due to the pressure difference, violently tearing her apart (Wired 2009).
As we can conclude the Hindenburg was not the first airship disaster, and neither was it the deadliest, but definitely the most dramatic. It pretty much ended airship travel overnight. Today, we are seeing many new ideas emerge in respect to modern airships. One that caught my attention was that of a proposed hybrid model airships which include more robust material and efficient power solutions such as ultracapacitors which is an energy storage technology backed by Tesla. These ultracapacitors are able to give a short limited burst of energy in order to stabilize or accelerate the airship and is able to rapidly recharge on its own (CNBC 2016).
Now, since this is an engineering disasters course, we would have to look at it from the perspective of a failure analyst. One method Professor Halada mentioned was the use of an X-ray fluorescence gun containing a fifty thousand volt x-ray source. What this gun does is it displaces electrons from their atomic orbital positions; while releasing a burst of energy that is characteristic of a specific element (Bruker). In other words, it shows you the energy of x-rays that are being emitted from a sample, along with listing some of the elemental compositions found in the material.
In the first assignment we were ever given, I spoke about fidget spinners and its failures. One thing I mentioned was that these toys contained lead since there were no standards that the manufacturers had to meet. Using the XRF gun, engineers; or even consumers can test the elements found in these gadgets, or in virtually any material that they can get their hands on. Giving us a sense of security that we can depend on.
We live in an era where our skies are ruled by commercial jets, and helicopters; but we must never forget that the reason why those massive pieces of composites are up there now, is because a lot of them came down years ago. With every failure we faced in regards to air travel, a very important lesson was drawn. Today, we still do hear about aircraft incidents. And I'm sure as time progresses that won't change, but I'll tell you one thing: It will get better. What really intrigued me is how much history is around us, so close to home. We really have to take a minute to take it all in. I've learned so much with this assignment and this lecture that I'm slowly and surely starting to be capable of putting meat on the abstract bones of engineering disasters.
"The only real mistake is the one from which we learn nothing."