In addition to Dick's observations, during the "Graf Zeppelin II's" early test flights, measurements were taken of the airship's static charge. Dr. Ludwig Durr and the other engineers at Luftschiffbau Zeppelin took the static discharge hypothesis seriously and considered the insulation of the fabric from the frame to be a design flaw in the "Hindenburg." Thus, the German Inquiry concluded that the insulation of the outer covering caused a spark to jump onto a nearby piece of metal, thereby igniting the hydrogen. In lab experiments, using the "Hindenburg's" outer covering and a static ignition, hydrogen was able to be ignited but with the covering of the LZ 127 "Graf Zeppelin," nothing happened. These findings were not well-publicized and were covered up, perhaps to avoid embarrassment of such an engineering flaw in the face of the Third Reich.