Flying the B-314, Cracks in the Wingspar
The B314 wingspar was made from a round tube of aluminum that was rolled into an almost square shape. During this process, some undetected cracks occurred. After the aircraft was built, they were detected, analyzed for strength, and stop drilled to prevent propagation. There was also an ink line at each end of the crack to locate the drilled holes and to confirm that the crack did not propagate. During flight, flight engineers were required to inspect all of the B314 that was accessible, every 2 hours. This included these cracks. The wings were large enough to accommodate a 'crawl way' out to #1 & #4 engines. We carried wrenches and a flashlight so we could repair any defects on the spot. As I remember it, one of the cracks was between #3 and #4 engine. None of these cracks ever spread. At times we carried a spare engine and hoist in our cargo area so we would not be stranded with a failed engine in the boondocks. The whole crew was trained to do this engine change without help. Since the engine was larger than the hatch, the cylinders had to be installed after the crankcase was placed on top of the wing. I don't believe this was ever done. However, one of our intrepid engineers did change a defective magneto during flight using a good magneto from the spare engine. If he is still alive, he could give us the details of this extraordinary event. This 'can do' attitude was typical of Pan Am in those days.