The damage they were fixing. It was in 1928 I believe though? That's the Atlantic flight, and indeed they fixed a broken tail fin on that flight. It was thought lost, radio stations played a minute of silence and prayerea and stuff. Once they made it to America, people got mad at them for not responding by radio but it was because they had to slow down so much to repair they lost electricity to the radio (generated by turbines powered by forward motion)

For what it's worth, the outer skin here is treated canvas, for aerodynamics. It doesn't function to contain the lifting gas. That's stored in a series of inner balloons inside the steel superstructure.